Mindy Tsai
Sr Res Scientist-Basic Ls, Pathology Sponsored Projects
Bio
Mindy Tsai is Sr. Research Scientist in the Department of Pathology. She received the D.M.Sc. (Doctor of Medical Sciences) in Oral Biology from Harvard School of Dental Medicine and completed her postdoctoral training at Harvard Medical School. Dr. Tsai’s research focuses on studies that are designed to understand the regulation of mast cell and basophil development and to elucidate the roles of these cells in health and disease. Dr. Tsai’s research approaches include in vitro analyses of mast cells and basophils in human and mice, as well as using mouse models of disease to investigate the effector and immunoregulatory functions of these cells in vivo.
Contact
https://orcid.org/0000-0002-8421-4721All Publications
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Combining avidin with CD63 improves basophil activation test accuracy in classifying peanut allergy.
Allergy
2023
Abstract
Conventional basophil activation tests (BATs) measure basophil activation by the increased expression of CD63. Previously, fluorophore-labeled avidin, a positively-charged molecule, was found to bind to activated basophils, which tend to expose negatively charged granule constituents during degranulation. This study further compares avidin versus CD63 as basophil activation biomarkers in classifying peanut allergy.Seventy subjects with either a peanut allergy (N = 47), a food allergy other than peanut (N = 6), or no food allergy (N = 17) were evaluated. We conducted BATs in response to seven peanut extract (PE) concentrations (0.01-10,000 ng/mL) and four control conditions (no stimulant, anti-IgE, fMLP (N-formylmethionine-leucyl-phenylalanine), and anti-FcεRI). We measured avidin binding and CD63 expression on basophils with flow cytometry. We evaluated logistic regression and XGBoost models for peanut allergy classification and feature identification.Avidin binding was correlated with CD63 expression. Both markers discriminated between subjects with and without a peanut allergy. Although small by percentage, an avidin+ /CD63- cell subset was found in all allergic subjects tested, indicating that the combination of avidin and CD63 could allow a more comprehensive identification of activated basophils. Indeed, we obtained the best classification accuracy (97.8% sensitivity, 96.7% specificity) by combining avidin and CD63 across seven PE doses. Similar accuracy was obtained by combining PE dose of 10,000 ng/mL for avidin and PE doses of 10 and 100 ng/mL for CD63.Avidin and CD63 are reliable BAT activation markers associated with degranulation. Their combination enhances the identification of activated basophils and improves the classification accuracy of peanut allergy.
View details for DOI 10.1111/all.15930
View details for PubMedID 37916710
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CD8+ T cell differentiation status correlates with the feasibility of sustained unresponsiveness following oral immunotherapy.
Nature communications
2022; 13 (1): 6646
Abstract
While food allergy oral immunotherapy (OIT) can provide safe and effective desensitization (DS), the immune mechanisms underlying development of sustained unresponsiveness (SU) following a period of avoidance are largely unknown. Here, we compare high dimensional phenotypes of innate and adaptive immune cell subsets of participants in a previously reported, phase 2 randomized, controlled, peanut OIT trial who achieved SU vs. DS (no vs. with allergic reactions upon food challenge after a withdrawal period; n=21 vs. 30 respectively among total 120 intent-to-treat participants). Lower frequencies of naive CD8+ T cells and terminally differentiated CD57+CD8+ T cell subsets at baseline (pre-OIT) are associated with SU. Frequency of naive CD8+ T cells shows a significant positive correlation with peanut-specific and Ara h 2-specific IgE levels at baseline. Higher frequencies of IL-4+ and IFNgamma+ CD4+ T cells post-OIT are negatively correlated with SU. Our findings provide evidence that an immune signature consisting of certain CD8+ T cell subset frequencies is potentially predictive of SU following OIT.
View details for DOI 10.1038/s41467-022-34222-8
View details for PubMedID 36333296
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An optimized protocol for phenotyping human granulocytes by mass cytometry.
STAR protocols
2022; 3 (2): 101280
Abstract
Granulocytes encompass diverse roles, from fighting off pathogens to regulating inflammatory processes in allergies. These roles are represented by distinct cellular phenotypes that we captured with mass cytometry (CyTOF). Our protocol enables simultaneous evaluation of human basophils, eosinophils, and neutrophils under homeostasis and upon immune activation by anti-Immunoglobulin E (anti-IgE) or interleukin-3 (IL-3). Granulocyte integrity and detection of protein markers were optimized so that rare granulocyte populations could be deeply characterized by single cell mass cytometry. For complete details on the use and execution of this protocol, please refer to Vivanco Gonzalez etal. (2020).
View details for DOI 10.1016/j.xpro.2022.101280
View details for PubMedID 35434655
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Dynamin Related Protein 1 Differentially Regulates FcepsilonRI- and SP-induced Mast Cell Activation.
The Journal of allergy and clinical immunology
2022
Abstract
BACKGROUND: The mitochondrial fission protein, dynamin related protein 1 (Drp1), has been suggested to regulate mast cell (MC) activation by certain stimuli in vitro but its functions in MCs activated by various stimuli in vivo has not been examined.OBJECTIVE: Analyze Drp1 function in both mouse and human MCs.METHODS: We used human peripheral blood-derived cultured MCs (PBCMCs) and two genetic mouse models in which MCs were depleted of Drp1: Drp1fl/flMcpt5cre+/- mice and Drp1fl/flCpa3cre+/- mice.RESULTS: In mice, Drp1 depletion enhanced FcepsilonRI-induced MC activation while suppressing substance P (SP)-stimulated MC activation in vitro and in vivo. This was also true in human PBCMCs in vitro after pharmacological inhibition of Drp1.CONCLUSION: Our work shows that Drp1 differentially regulates MC activation by various stimuli. These findings suggest that promoting Drp1 activation might represent a novel therapy for suppressing IgE-dependent MC activation while inhibiting Drp1 activation might mitigate other MC-dependent responses, such as those induced by substance P.
View details for DOI 10.1016/j.jaci.2022.04.028
View details for PubMedID 35561839
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KIT as a master regulator of the mast cell lineage.
The Journal of allergy and clinical immunology
2022
Abstract
The discovery in 1987/1988 and 1990 of the cell-surface receptor KIT and its ligand, stem cell factor (SCF), were critical achievements in efforts to understand the development and function of multiple distinct cell lineages. These include hematopoietic progenitors, melanocytes, germ cells, and mast cells, which all are significantly affected by loss-of-function mutations of KIT or SCF. Such mutations also influence the development and/or function of additional cells, including those in parts of the CNS and the interstitial cells of Cajal (that control gut motility). Many other cells can express KIT constitutively or during immune responses, including dendritic cells, eosinophils, ILC2 cells, and taste cells. Yet the biological importance of KIT in many of these cell types largely remains to be determined. We here review the history of work investigating mice with mutations affecting the W locus (that encodes KIT) or the Sl locus (that encodes SCF), focusing especially on the influence of such mutations on mast cells. We also briefly review efforts to target the KIT/SCF pathway with anti-SCF or anti-KIT antibodies in mouse models of allergic disorders, parasite immunity, or fibrosis in which MCs are thought to play significant roles.
View details for DOI 10.1016/j.jaci.2022.04.012
View details for PubMedID 35469840
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Assessment of Allergic and Anaphylactic Reactions to mRNA COVID-19 Vaccines With Confirmatory Testing in a US Regional Health System.
JAMA network open
2021; 4 (9): e2125524
Abstract
Importance: As of May 2021, more than 32 million cases of COVID-19 have been confirmed in the United States, resulting in more than 615 000 deaths. Anaphylactic reactions associated with the Food and Drug Administration (FDA)-authorized mRNA COVID-19 vaccines have been reported.Objective: To characterize the immunologic mechanisms underlying allergic reactions to these vaccines.Design, Setting, and Participants: This case series included 22 patients with suspected allergic reactions to mRNA COVID-19 vaccines between December 18, 2020, and January 27, 2021, at a large regional health care network. Participants were individuals who received at least 1 of the following International Statistical Classification of Diseases and Related Health Problems, Tenth Revision anaphylaxis codes: T78.2XXA, T80.52XA, T78.2XXD, or E949.9, with documentation of COVID-19 vaccination. Suspected allergy cases were identified and invited for follow-up allergy testing.Exposures: FDA-authorized mRNA COVID-19 vaccines.Main Outcomes and Measures: Allergic reactions were graded using standard definitions, including Brighton criteria. Skin prick testing was conducted to polyethylene glycol (PEG) and polysorbate 80 (P80). Histamine (1 mg/mL) and filtered saline (negative control) were used for internal validation. Basophil activation testing after stimulation for 30 minutes at 37 °C was also conducted. Concentrations of immunoglobulin (Ig) G and IgE antibodies to PEG were obtained to determine possible mechanisms.Results: Of 22 patients (20 [91%] women; mean [SD] age, 40.9 [10.3] years; 15 [68%] with clinical allergy history), 17 (77%) met Brighton anaphylaxis criteria. All reactions fully resolved. Of patients who underwent skin prick tests, 0 of 11 tested positive to PEG, 0 of 11 tested positive to P80, and 1 of 10 (10%) tested positive to the same brand of mRNA vaccine used to vaccinate that individual. Among these same participants, 10 of 11 (91%) had positive basophil activation test results to PEG and 11 of 11 (100%) had positive basophil activation test results to their administered mRNA vaccine. No PEG IgE was detected; instead, PEG IgG was found in tested individuals who had an allergy to the vaccine.Conclusions and Relevance: Based on this case series, women and those with a history of allergic reactions appear at have an elevated risk of mRNA vaccine allergy. Immunological testing suggests non-IgE-mediated immune responses to PEG may be responsible in most individuals.
View details for DOI 10.1001/jamanetworkopen.2021.25524
View details for PubMedID 34533570
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The role of Sp140 revealed in IgE and mast cell responses in Collaborative Cross mice.
JCI insight
2021; 6 (12)
Abstract
Mouse IgE and mast cell (MC) functions have been studied primarily using inbred strains. Here, we (a) identified effects of genetic background on mouse IgE and MC phenotypes, (b) defined the suitability of various strains for studying IgE and MC functions, and (c) began to study potentially novel genes involved in such functions. We screened 47 Collaborative Cross (CC) strains, as well as C57BL/6J and BALB/cJ mice, for strength of passive cutaneous anaphylaxis (PCA) and responses to the intestinal parasite Strongyloides venezuelensis (S.v.). CC mice exhibited a diversity in PCA strength and S.v. responses. Among strains tested, C57BL/6J and CC027 mice showed, respectively, moderate and uniquely potent MC activity. Quantitative trait locus analysis and RNA sequencing of BM-derived cultured MCs (BMCMCs) from CC027 mice suggested Sp140 as a candidate gene for MC activation. siRNA-mediated knock-down of Sp140 in BMCMCs decreased IgE-dependent histamine release and cytokine production. Our results demonstrated marked variations in IgE and MC activity in vivo, and in responses to S.v., across CC strains. C57BL/6J and CC027 represent useful models for studying MC functions. Additionally, we identified Sp140 as a gene that contributes to IgE-dependent MC activation.
View details for DOI 10.1172/jci.insight.146572
View details for PubMedID 34156030
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IgE antibodies increase honeybee venom responsiveness and detoxification efficiency of mast cells.
Allergy
2021
Abstract
BACKGROUND: In contrast to theirclearly defined rolesin allergic diseases, the physiologic functions of Immunoglobulin E antibodies (IgEs) and mast cells (MCs) remainenigmatic. Recent research supports the toxin hypothesis,showing thatMCs and IgE-related type 2 immune responses can enhance host defense against certain noxious substances, including honeybee venom (BV). However, the mechanisms by whichMCs can interfere with BV toxicity are unknown. In this study, we assessed the role of IgE andcertain MC products inMC-mediated BV detoxification.METHODS: We appliedin vitro and in vivofluorescence microscopyimaging, andflow cytometry,fibroblast-based toxicity assaysand mass spectrometry to investigate IgE-mediated detoxification of BV cytotoxicity by mouse and human MCs in vitro. Pharmacologic strategies to interfere with MC-derived heparin and proteaseshelped to define the importance of specific detoxification mechanisms.RESULTS: Venom-specific IgE increased the degranulation and cytokineresponses of MCs to BVin vitro. Passive serum sensitization enhanced MC degranulationin vivo. IgE-activated mouse or human MCs exhibited enhanced potential for detoxifying BV by both proteolytic degradation and heparin-related interference with toxicity.Mediators released by IgE-activated human MCs efficiently degraded multiple BV toxins.CONCLUSIONS: Our results both revealthat IgEsensitization enhances the MC's ability to detoxify BVand alsoassign efficienttoxin-neutralizing activity to MC-derivedheparin and proteases. Our study thus highlights the potential importance of IgE, MCs, and particular MC products in defense against BV.
View details for DOI 10.1111/all.14852
View details for PubMedID 33840121
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Basophil activation tests identify a peanut OIT subgroup with improved safety and outcomes
MOSBY-ELSEVIER. 2021: AB166
View details for Web of Science ID 000629158000529
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Transcriptome programmingof IL-3-dependent bone marrow-derived cultured mast cells by stem cell factor (SCF).
Allergy
2021
View details for DOI 10.1111/all.14808
View details for PubMedID 33683709
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E-cadherin is regulated by GATA-2 and marks the early commitment of mouse hematopoietic progenitors to the basophil and mast cell fates.
Science immunology
2021; 6 (56)
Abstract
E-cadherin is a calcium-dependent cell-cell adhesion molecule extensively studied for its involvement in tissue formation, epithelial cell behavior, and suppression of cancer. However, E-cadherin expression in the hematopoietic system has not been fully elucidated. Combining single-cell RNA-sequencing analyses and immunophenotyping, we revealed that progenitors expressing high levels of E-cadherin and contained within the granulocyte-monocyte progenitors (GMPs) fraction have an enriched capacity to differentiate into basophils and mast cells. We detected E-cadherin expression on committed progenitors before the expression of other reported markers of these lineages. We named such progenitors pro-BMPs (pro-basophil and mast cell progenitors). Using RNA sequencing, we observed transcriptional priming of pro-BMPs to the basophil and mast cell lineages. We also showed that GATA-2 directly regulates E-cadherin expression in the basophil and mast cell lineages, thus providing a mechanistic connection between the expression of this cell surface marker and the basophil and mast cell fate specification.
View details for DOI 10.1126/sciimmunol.aba0178
View details for PubMedID 33547048
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Basophil activation test shows high accuracy in the diagnosis of peanut and tree nut allergy: The Markers of Nut Allergy Study.
Allergy
2020
Abstract
BACKGROUND: Peanut and tree nut allergies are the most important causes of anaphylaxis. Co-reactivity to more than one nut is frequent, and co-sensitization in the absence of clinical data is often obtained. Confirmatory oral food challenges (OFCs) are inconsistently performed.OBJECTIVE: To investigate the utility of the basophil activation test (BAT) in diagnosing peanut and tree nut allergy.METHODS: The Markers Of Nut Allergy Study (MONAS) prospectively enrolled patients aged 0.5-17 years with confirmed peanut and/or tree nut (almond, cashew, hazelnut, pistachio, walnut) allergy or sensitization fromCanadian (n=150) and Austrian (n=50) tertiary pediatric centers. BAT using %CD63+ basophils (SSClow/CCR3pos) as outcome was performed with whole blood samples stimulated with allergen extracts of each nut (0.001-1000ng/mL protein). BAT results were assessed against confirmed allergic status in a blinded fashion to develop a generalizable statistical model for comparisonto extract and marker allergen-specificIgE.RESULTS: A mixed effect model integrating BAT results for 10 and 100 ng/mL of peanut and individual tree nut extracts was optimal. The area under the ROC curve (AUROC) was 0.98 for peanut, 0.97 for cashew, 0.92 for hazelnut, 0.95 for pistachio, and 0.97 for walnut. The BAT outperformed sIgE testing for peanut or hazelnut and was comparable for walnut (AUROC 0.95, 0.94, 0.92) ina sub-analysis in sensitized patients undergoing OFC.CONCLUSIONS: BAT can predict allergic clinical status to peanut and tree nuts in multi-nut sensitized children and may reduce the need for high-risk OFCs in patients.
View details for DOI 10.1111/all.14695
View details for PubMedID 33300157
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Mass Cytometry Phenotyping of Human Granulocytes Reveals Novel Basophil Functional Heterogeneity.
iScience
2020; 23 (11): 101724
Abstract
Basophils, the rarest granulocyte, play critical roles in parasite- and allergen-induced inflammation. We applied mass cytometry (CyTOF) to simultaneously asses 44 proteins to phenotype and functionally characterize neutrophils, eosinophils, and basophils from 19 healthy donors. There was minimal heterogeneity seen in eosinophils and neutrophils, but data-driven analyses revealed four unique subpopulations within phenotypically basophilic granulocytes (PBG; CD45+HLA-DR-CD123+). Through CyTOF and fluorescence-activated cell sorting (FACS), we classified these four PBG subpopulations as (I) CD16lowFcepsilonRIhighCD244high (88.5± 1.2%), (II) CD16highFcepsilonRIhighCD244high (9.1± 0.4%), (III) CD16lowFcepsilonRIlowCD244low (2.3± 1.3), and (IV) CD16highFcepsilonRIlowCD244low (0.4± 0.1%). Prospective isolation confirmed basophilic-morphology of PBG I-III, but neutrophilic-morphology of PBG IV. Functional interrogation via IgE-crosslinking or IL-3 stimulation demonstrated that PBG I-II had significant increases in CD203c expression, whereas PBG III-IV remained unchanged compared with media-alone conditions. Thus, PBG III-IV could serve roles in non-IgE-mediated immunity. Our findings offer new perspectives in human basophil heterogeneity and the varying functional potential of these new subsets in health and disease.
View details for DOI 10.1016/j.isci.2020.101724
View details for PubMedID 33205028
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Mast cells and IgE in defense against lethality of venoms: Possible "benefit" of allergy[].
Allergo journal international
2020; 29 (2): 46–62
Abstract
Physicians think of mast cells and IgE primarily in the context of allergic disorders, including fatal anaphylaxis. This 'bad side' of mast cells and IgE is so well accepted that it can be difficult to think of them in other contexts, particularly those in which they may have beneficial functions. However, there is evidence that mast cells and IgE, as well as basophils (circulating granulocytes whose functions partially overlap with those of mast cells), can contribute to host defense as components of adaptive type 2 immune responses to helminths, ticks and certain other parasites. Accordingly, allergies often are conceptualized as "misdirected" type 2 immune responses, in which IgE antibodies are produced against any of a diverse group of apparently harmless antigens, and against components of animal venoms. Indeed, certain unfortunate patients who have become sensitized to venoms develop severe IgE-associated allergic reactions, including fatal anaphylaxis, upon subsequent venom exposure. In this review, we will describe evidence that mast cells can enhance innate resistance, and survival, to challenge with reptile or arthropod venoms during a first exposure to such venoms. We also will discuss findings indicating that, in mice surviving an initial encounter with venom, acquired type 2 immune responses, IgE antibodies, the high affinity IgE receptor (FcepsilonRI), and mast cells can contribute to acquired resistance to the lethal effects of both honeybee venom and Russell's viper venom. These findings support the hypothesis that mast cells and IgE can help protect the host against venoms and perhaps other noxious substances.
View details for DOI 10.1007/s40629-020-00118-6
View details for PubMedID 33224714
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Dose-related Allergic Reactions Decrease Over Time During Peanut Oral Immunotherapy in a Large, Randomized, Double-blind, Placebo-controlled, Phase 2 Study
MOSBY-ELSEVIER. 2020: AB134
View details for Web of Science ID 000517092700425
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Sustained outcomes in oral immunotherapy for peanut allergy (POISED study): a large, randomised, double-blind, placebo-controlled, phase 2 study
MOSBY-ELSEVIER. 2020: AB181
View details for Web of Science ID 000517092700578
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Legends of Allergy: Stephen J. Galli
ALLERGY
2020; 75 (1): 243–45
View details for DOI 10.1111/all.13815
View details for Web of Science ID 000506187800034
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Microfluidic methods for precision diagnostics in food allergy.
Biomicrofluidics
2020; 14 (2): 021503
Abstract
Food allergy has reached epidemic proportions and has become a significant source of healthcare burden. Oral food challenge, the gold standard for food allergy assessment, often is not performed because it places the patient at risk of developing anaphylaxis. However, conventional alternative food allergy tests lack a sufficient predictive value. Therefore, there is a critical need for better diagnostic tests that are both accurate and safe. Microfluidic methods have the potential of helping one to address such needs and to personalize the diagnostics. This article first reviews conventional diagnostic approaches used in food allergy. Second, it reviews recent efforts to develop novel biomarkers and in vitro diagnostics. Third, it summarizes the microfluidic methods developed thus far for food allergy diagnosis. The article concludes with a discussion of future opportunities for using microfluidic methods for achieving precision diagnostics in food allergy, including multiplexing the detection of multiple biomarkers, sampling of tissue-resident cytokines and immune cells, and multi-organ-on-a-chip technology.
View details for DOI 10.1063/1.5144135
View details for PubMedID 32266046
View details for PubMedCentralID PMC7127910
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Origins and clonal convergence of gastrointestinal IgE+ B cells in human peanut allergy.
Science immunology
2020; 5 (45)
Abstract
B cells in human food allergy have been studied predominantly in the blood. Little is known about IgE+ B cells or plasma cells in tissues exposed to dietary antigens. We characterized IgE+ clones in blood, stomach, duodenum, and esophagus of 19 peanut-allergic patients, using high-throughput DNA sequencing. IgE+ cells in allergic patients are enriched in stomach and duodenum, and have a plasma cell phenotype. Clonally related IgE+ and non-IgE-expressing cell frequencies in tissues suggest local isotype switching, including transitions between IgA and IgE isotypes. Highly similar antibody sequences specific for peanut allergen Ara h 2 are shared between patients, indicating that common immunoglobulin genetic rearrangements may contribute to pathogenesis. These data define the gastrointestinal tract as a reservoir of IgE+ B lineage cells in food allergy.
View details for DOI 10.1126/sciimmunol.aay4209
View details for PubMedID 32139586
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Gastrointestinal Eosinophil Responses in a Longitudinal, Randomized Trial of Peanut Oral Immunotherapy.
Clinical gastroenterology and hepatology : the official clinical practice journal of the American Gastroenterological Association
2020
Abstract
Gastrointestinal side effects are common during oral immunotherapy (OIT) and eosinophilic esophagitis (EoE) is a potential complication. We aimed to characterize eosinophilic gastrointestinal responses to peanut OIT, in which peanut protein is given orally, with incremental increases in dose over time.Twenty adults with IgE-mediated peanut allergy were randomly assigned to groups given peanut OIT (n=15) or placebo (n=5); 1 additional subject withdrew before randomization. Serial gastrointestinal biopsies were collected at baseline (n=21, 0 weeks), following dose escalation (n=10, 52 weeks), and during the maintenance phase (n=11, 104 weeks). Endoscopic findings were characterized using the EoE endoscopic reference score. Biopsies were assessed for eosinophils per high-power field (eos/hpf) and other pathology features using EoE histologic scoring system scores. We performed immunohistochemical analyses of eosinophil peroxidase deposition, quantified using automated image analysis.At baseline, no subjects reported current gastrointestinal symptoms. However, 3 of the 21 subjects (14%) had esophageal peak eosinophil counts ≥15 eos/hpf and all subjects had dilated intercellular spaces (DIS). OIT induced or exacerbated esophageal eosinophilia (EE) at 52 weeks in most subjects (peak eosinophil counts >5 eos/hpf in 6 of 7 patients [86%]; peak eosinophil counts ≥15 eos/hpf in 4 of 7 patients [57%]). One subject met clinicopathologic criteria for EoE and withdrew; no significant changes in esophageal peak eosinophil counts were observed in the placebo group. EE in the OIT group corresponded with significant increases in EoE histologic scoring system scores and deposition of eosinophil peroxidase. In 4 of 6 participants (67%), OIT-induced EE and gastrointestinal eosinophilia resolved by the end of the maintenance phase. Gastrointestinal symptoms were not clearly associated with EE or gastrointestinal eosinophilia.In this pilot study, we found that peanut OIT-induced EE and gastrointestinal eosinophilia are usually transient and are not always associated with gastrointestinal symptoms. Clinicaltrials.gov no: NCT02103270.
View details for DOI 10.1016/j.cgh.2020.05.019
View details for PubMedID 32434067
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Mast Cells in Inflammation and Disease: Recent Progress and Ongoing Concerns.
Annual review of immunology
2020; 38: 49–77
Abstract
Mast cells have existed long before the development of adaptive immunity, although they have been given different names. Thus, in the marine urochordate Styela plicata, they have been designated as test cells. However, based on their morphological characteristics (including prominent cytoplasmic granules) and mediator content (including heparin, histamine, and neutral proteases), test cells are thought to represent members of the lineage known in vertebrates as mast cells. So this lineage presumably had important functions that preceded the development of antibodies, including IgE. Yet mast cells are best known, in humans, as key sources of mediators responsible for acute allergic reactions, notably including anaphylaxis, a severe and potentially fatal IgE-dependent immediate hypersensitivity reaction to apparently harmless antigens, including many found in foods and medicines. In this review, we briefly describe the origins of tissue mast cells and outline evidence that these cells can have beneficial as well as detrimental functions, both innately and as participants in adaptive immune responses. We also discuss aspects of mast cell heterogeneity and comment on how the plasticity of this lineage may provide insight into its roles in health and disease. Finally, we consider some currently open questions that are yet unresolved.
View details for DOI 10.1146/annurev-immunol-071719-094903
View details for PubMedID 32340580
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Oral Immunotherapy and Basophil and Mast Cell Reactivity in Food Allergy.
Frontiers in immunology
2020; 11: 602660
Abstract
Basophil activation tests (BATs) can closely monitor, in vitro, a patient's propensity to develop type I hypersensitivity reactions. Because of their high specificity and sensitivity, BATs have become promising diagnostic tools, especially in cases with equivocal clinical histories, skin prick test results, and/or levels of specific IgE to allergen extracts. BATs also are useful as tools for monitoring the effects of treatment, since oral immunotherapy (OIT) studies report a diminution in patients' basophil responsiveness over the course of OIT. This review will discuss the BAT findings obtained before, during, and after OIT for food allergy. We will mainly focus on the association of basophil responsiveness, and alterations in basophil surface markers, with clinical outcomes and other clinical features, such as blood levels of specific IgG and IgE antibodies. The detailed analysis of these correlations will ultimately facilitate the use of BATs, along with other blood biomarkers, to differentiate short-term desensitization versus sustained unresponsiveness and to improve treatment protocols. Given the critical anatomic location of mast cells adjacent to the many IgE+ plasma cells found in the gastrointestinal tissues of allergic individuals, we will also discuss the role of gastrointestinal mast cells in manifestations of food allergies.
View details for DOI 10.3389/fimmu.2020.602660
View details for PubMedID 33381123
View details for PubMedCentralID PMC7768812
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Epithelial RABGEF1 deficiency promotes intestinal inflammation by dysregulating intrinsic MYD88-dependent innate signaling.
Mucosal immunology
2019
Abstract
Intestinal epithelial cells (IECs) contribute to the regulation of intestinal homeostasis and inflammation through their interactions with the environment and host immune responses. Yet our understanding of IEC-intrinsic regulatory pathways remains incomplete. Here, we identify the guanine nucleotide exchange factor RABGEF1 as a regulator of intestinal homeostasis and innate pathways dependent on IECs. Mice with IEC-specific Rabgef1 deletion (called Rabgef1IEC-KO mice) developed a delayed spontaneous colitis associated with the local upregulation of IEC chemokine expression. In mouse models of colitis based on Interleukin-10 deficiency or dextran sodium sulfate (DSS) exposure, we found that IEC-intrinsic RABGEF1 deficiency exacerbated development of intestinal pathology and dysregulated IEC innate pathways and chemokine expression. Mechanistically, we showed that RABGEF1 deficiency in mouse IECs in vitro was associated with an impairment of early endocytic events, an increased activation of the p38 mitogen-activated protein kinase (MAPK)-dependent pathway, and increased chemokine secretion. Moreover, we provided evidence that the development of spontaneous colitis was dependent on microbiota-derived signals and intrinsic MYD88-dependent pathways in vivo. Our study identifies mouse RABGEF1 as an important regulator of intestinal inflammation, MYD88-dependent IEC-intrinsic signaling, and chemokine production. This suggests that RABGEF1-dependent pathways represent interesting therapeutic targets for inflammatory conditions in the gut.
View details for DOI 10.1038/s41385-019-0211-z
View details for PubMedID 31628426
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IgE-mediated mast cell activation promotes inflammation and cartilage destruction in osteoarthritis
ELIFE
2019; 8
View details for DOI 10.7554/eLife.39905
View details for Web of Science ID 000467895900001
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Legends of Allergy: Stephen J. Galli.
Allergy
2019
Abstract
Professor Stephen J. Galli's rigorous and innovative research in the field of allergy and immunology has truly made him a legend in the field. His accomplishments are many as are the awards and recognitions he has received. He and his team have published approximately 430 peer-reviewed publications and 14 patents. He has chaired, organized, or co-organized 16 scientific meetings or symposia. Some of the major awards he has received are the MERIT award from NIAID/NIH (1995), Scientific Achievement Award from the International Association of Allergy and Clinical Immunology (1997), Scientific Achievement Award from the World Allergy Organization (2011), Rous-Whipple Award of the American Society for Investigative Pathology (2014), and the Karl Landsteiner Medal of the Austrian Society of Allergology and Immunology (2014). This article is protected by copyright. All rights reserved.
View details for PubMedID 30964544
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Basophil-derived tumor necrosis factor can enhance survival in a sepsis model in mice.
Nature immunology
2019; 20 (2): 129–40
Abstract
Basophils are evolutionarily conserved in vertebrates, despite their small numbers and short life span, suggesting that they have beneficial roles in maintaining health. However, these roles are not fully defined. Here we demonstrate that basophil-deficient mice exhibit reduced bacterial clearance and increased morbidity and mortality in the cecal ligation and puncture (CLP) model of sepsis. Among the several proinflammatory mediators that we measured, tumor necrosis factor (TNF) was the only cytokine that was significantly reduced in basophil-deficient mice after CLP. In accordance with that observation, we found that mice with genetic ablation of Tnf in basophils exhibited reduced systemic concentrations of TNF during endotoxemia. Moreover, after CLP, mice whose basophils could not produce TNF, exhibited reduced neutrophil and macrophage TNF production and effector functions, reduced bacterial clearance, and increased mortality. Taken together, our results show that basophils can enhance the innate immune response to bacterial infection and help prevent sepsis.
View details for PubMedID 30664762
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Basophil-derived tumor necrosis factor can enhance survival in a sepsis model in mice
NATURE IMMUNOLOGY
2019; 20 (2): 129-+
View details for DOI 10.1038/s41590-018-0288-7
View details for Web of Science ID 000456279100011
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Esophageal Eosinophilia is Present in Some Peanut Allergic Patients
MOSBY-ELSEVIER. 2019: AB310
View details for DOI 10.1016/j.jaci.2018.12.942
View details for Web of Science ID 000457771200928
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Development of multiple features of antigen-induced asthma pathology in a new strain of mast cell deficient BALB/c-KitW-sh/W-sh mice.
Laboratory investigation; a journal of technical methods and pathology
2019
Abstract
Mast cell-deficient mice are widely used to identify and quantify contributions of mast cells to diverse biological responses in vivo, including allergic inflammation. However, despite the fact that scores of genes have been identified as modifiers of allergic inflammation, most mast cell-deficient models have been available only on a single genetic background. We transferred the KitW-sh allele onto the BALB/c background to generate BALB/c mast cell-deficient mice (BALB/c-KitW-sh/W-sh). BALB/c-KitW-sh/W-sh mice have dramatically reduced mast cell numbers (0-2% of wild type) in all tissues examined, as well as subtle hematologic differences from the corresponding wild type mice, including splenomegaly with evidence of increased splenic hematopoiesis. We examined in BALB/c-KitW-sh/W-sh mice models of allergic inflammation that are substantially diminished in C57BL/6-KitW-sh/W-sh mast cell-deficient mice. In a model of acute allergic inflammation, i.e., IgE-dependent passive cutaneous anaphylaxis, both ear swelling and leukocyte infiltration were largely or entirely absent in BALB/c-KitW-sh/W-sh mice. In contrast, in two different models of allergic airway inflammation, airway hyperresponsiveness, lung inflammation, and airway remodeling developed robustly in mast cell-deficient BALB/c-KitW-sh/W-sh mice. These results support the conclusion that the importance of mast cell contributions in various models of allergic inflammation may be at least partially determined by genetic background.
View details for DOI 10.1038/s41374-019-0354-2
View details for PubMedID 31857699
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Sustained Successful Peanut Oral Immunotherapy Associated with Low Basophil Activation and Peanut-Specific IgE.
The Journal of allergy and clinical immunology
2019
Abstract
Oral immunotherapy (OIT) can successfully desensitize many peanut allergic subjects, but clinical tolerance diminishes over time upon discontinuation, or low dose maintenance, of peanut. Therefore, in order to improve the efficacy and sustainability of such therapy, we sought to identify biomarkers and clinical tools that can predict therapeutic outcomes and monitor treatment responses.We evaluated whether basophil activation in whole blood, and plasma levels of peanut-specific immunoglobulins, are useful biomarkers for peanut OIT.We longitudinally measured, before, during and after OIT, basophil activation in whole blood ex vivo in response to peanut stimulation, and peanut-specific IgE and IgG4, in a large, single-site, double-blind, randomized, placebo-controlled, phase 2 peanut OIT study. We compared basophil responsiveness and peanut specific immunoglobulins between those who were clinically reactive vs. tolerant to peanut oral challenges.Peanut OIT significantly decreased basophil activation, peanut-specific, Ara h 1, Ara h 2 and Ara h 3 IgEs, and sIgE/total IgE, but increased sIgG4/sIgE. Participants who became reactive to 4 g of peanut 13 weeks off active OIT exhibited higher peanut-induced basophil activation ex vivo and higher peanut-specific IgEs and sIgE/total IgE, but lower sIgG4/sIgE. Notably, participants entering the study with low basophil responsiveness were more likely to achieve treatment success. Substantial suppression of basophil activation was required to maintain long-term clinical tolerance after peanut OIT.Assessments of peanut-specific basophil activation and peanut-specific immunoglobulins can help to predict treatment outcomes, and to differentiate transient desensitization vs. sustained unresponsiveness after OIT.
View details for DOI 10.1016/j.jaci.2019.10.038
View details for PubMedID 31805311
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Sustained outcomes in oral immunotherapy for peanut allergy (POISED study): a large, randomised, double-blind, placebo-controlled, phase 2 study.
Lancet (London, England)
2019
Abstract
Dietary avoidance is recommended for peanut allergies. We evaluated the sustained effects of peanut allergy oral immunotherapy (OIT) in a randomised long-term study in adults and children.In this randomised, double-blind, placebo-controlled, phase 2 study, we enrolled participants at the Sean N Parker Center for Allergy and Asthma Research at Stanford University (Stanford, CA, USA) with peanut allergy aged 7-55 years with a positive result from a double-blind, placebo-controlled, food challenge (DBPCFC; ≤500 mg of peanut protein), a positive skin-prick test (SPT) result (≥5 mm wheal diameter above the negative control), and peanut-specific immunoglobulin (Ig)E concentration of more than 4 kU/L. Participants were randomly assigned (2·4:1·4:1) in a two-by-two block design via a computerised system to be built up and maintained on 4000 mg peanut protein through to week 104 then discontinued on peanut (peanut-0 group), to be built up and maintained on 4000 mg peanut protein through to week 104 then to ingest 300 mg peanut protein daily (peanut-300 group) for 52 weeks, or to receive oat flour (placebo group). DBPCFCs to 4000 mg peanut protein were done at baseline and weeks 104, 117, 130, 143, and 156. The pharmacist assigned treatment on the basis of a randomised computer list. Peanut or placebo (oat) flour was administered orally and participants and the study team were masked throughout by use of oat flour that was similar in look and feel to the peanut flour and nose clips, as tolerated, to mask taste. The statistician was also masked. The primary endpoint was the proportion of participants who passed DBPCFCs to a cumulative dose of 4000 mg at both 104 and 117 weeks. The primary efficacy analysis was done in the intention-to-treat population. Safety was assessed in the intention-to-treat population. This trial is registered at ClinicalTrials.gov, NCT02103270.Between April 15, 2014, and March 2, 2016, of 152 individuals assessed, we enrolled 120 participants, who were randomly assigned to the peanut-0 (n=60), peanut-300 (n=35), and placebo groups (n=25). 21 (35%) of peanut-0 group participants and one (4%) placebo group participant passed the 4000 mg challenge at both 104 and 117 weeks (odds ratio [OR] 12·7, 95% CI 1·8-554·8; p=0·0024). Over the entire study, the most common adverse events were mild gastrointestinal symptoms, which were seen in 90 of 120 patients (50/60 in the peanut-0 group, 29/35 in the peanut-300 group, and 11/25 in the placebo group) and skin disorders, which were seen in 50/120 patients (26/60 in the peanut-0 group, 15/35 in the peanut-300 group, and 9/25 in the placebo group). Adverse events decreased over time in all groups. Two participants in the peanut groups had serious adverse events during the 3-year study. In the peanut-0 group, in which eight (13%) of 60 participants passed DBPCFCs at week 156, higher baseline peanut-specific IgG4 to IgE ratio and lower Ara h 2 IgE and basophil activation responses were associated with sustained unresponsiveness. No treatment-related deaths occurred.Our study suggests that peanut OIT could desensitise individuals with peanut allergy to 4000 mg peanut protein but discontinuation, or even reduction to 300 mg daily, could increase the likelihood of regaining clinical reactivity to peanut. Since baseline blood tests correlated with week 117 treatment outcomes, this study might aid in optimal patient selection for this therapy.National Institute of Allergy and Infectious Diseases.
View details for DOI 10.1016/S0140-6736(19)31793-3
View details for PubMedID 31522849
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House dust mites activate nociceptor-mast cell clusters to drive type 2 skin inflammation.
Nature immunology
2019
Abstract
Allergic skin diseases, such as atopic dermatitis, are clinically characterized by severe itching and type 2 immunity-associated hypersensitivity to widely distributed allergens, including those derived from house dust mites (HDMs). Here we found that HDMs with cysteine protease activity directly activated peptidergic nociceptors, which are neuropeptide-producing nociceptive sensory neurons that express the ion channel TRPV1 and Tac1, the gene encoding the precursor for the neuropeptide substance P. Intravital imaging and genetic approaches indicated that HDM-activated nociceptors drive the development of allergic skin inflammation by inducing the degranulation of mast cells contiguous to such nociceptors, through the release of substance P and the activation of the cationic molecule receptor MRGPRB2 on mast cells. These data indicate that, after exposure to HDM allergens, activation of TRPV1+Tac1+ nociceptor-MRGPRB2+ mast cell sensory clusters represents a key early event in the development of allergic skin reactions.
View details for DOI 10.1038/s41590-019-0493-z
View details for PubMedID 31591569
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IgE-mediated mast cell activation promotes inflammation and cartilage destruction in osteoarthritis.
eLife
2019; 8
Abstract
Osteoarthritis is characterized by articular cartilage breakdown, and emerging evidence suggests that dysregulated innate immunity is likely involved. Here, we performed proteomic, transcriptomic, and electron microscopic analyses to demonstrate that mast cells are aberrantly activated in human and murine osteoarthritic joint tissues. Using genetic models of mast cell deficiency, we demonstrate that lack of mast cells attenuates osteoarthritis in mice. Using genetic and pharmacologic approaches, we show that the IgE/FcεRI/Syk signaling axis is critical for the development of osteoarthritis. We find that mast cell-derived tryptase induces inflammation, chondrocyte apoptosis, and cartilage breakdown. Our findings demonstrate a central role for IgE-dependent mast cell activation in the pathogenesis of osteoarthritis, suggesting that targeting mast cells could provide therapeutic benefit in human osteoarthritis.This article has been through an editorial process in which the authors decide how to respond to the issues raised during peer review. The Reviewing Editor's assessment is that all the issues have been addressed (see decision letter).
View details for PubMedID 31084709
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Baseline Gastrointestinal Eosinophilia Is Common in Oral Immunotherapy Subjects With IgE-Mediated Peanut Allergy
FRONTIERS IN IMMUNOLOGY
2018; 9
View details for DOI 10.3389/fimmu.2018.02624
View details for Web of Science ID 000450901300001
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Baseline Gastrointestinal Eosinophilia Is Common in Oral Immunotherapy Subjects With IgE-Mediated Peanut Allergy.
Frontiers in immunology
2018; 9: 2624
Abstract
Rationale: Oral immunotherapy (OIT) is an emerging treatment for food allergy. While desensitization is achieved in most subjects, many experience gastrointestinal symptoms and few develop eosinophilic gastrointestinal disease. It is unclear whether these subjects have subclinical gastrointestinal eosinophilia (GE) at baseline. We aimed to evaluate the presence of GE in subjects with food allergy before peanut OIT. Methods: We performed baseline esophagogastroduodenoscopies on 21 adults before undergoing peanut OIT. Subjects completed a detailed gastrointestinal symptom questionnaire. Endoscopic findings were assessed using the Eosinophilic Esophagitis (EoE) Endoscopic Reference Score (EREFS) and biopsies were obtained from the esophagus, gastric antrum, and duodenum. Esophageal biopsies were evaluated using the EoE Histologic Scoring System. Immunohistochemical staining for eosinophil peroxidase (EPX) was also performed. Hematoxylin and eosin and EPX stains of each biopsy were assessed for eosinophil density and EPX/mm2 was quantified using automated image analysis. Results: All subjects were asymptomatic. Pre-existing esophageal eosinophilia (>5 eosinophils per high-power field [eos/hpf]) was present in five participants (24%), three (14%) of whom had >15 eos/hpf associated with mild endoscopic findings (edema, linear furrowing, or rings; median EREFS = 0, IQR 0-0.25). Some subjects also demonstrated basal cell hyperplasia, dilated intercellular spaces, and lamina propria fibrosis. Increased eosinophils were noted in the gastric antrum (>12 eos/hpf) or duodenum (>26 eos/hpf) in 9 subjects (43%). EPX/mm2 correlated strongly with eosinophil counts (r = 0.71, p < 0.0001). Conclusions: Pre-existing GE is common in adults with IgE-mediated peanut allergy. Eosinophilic inflammation (EI) in these subjects may be accompanied by mild endoscopic and histologic findings. Longitudinal data collection during OIT is ongoing.
View details for DOI 10.3389/fimmu.2018.02624
View details for PubMedID 30524424
View details for PubMedCentralID PMC6261984
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Thirdhand smoke component can exacerbate a mouse asthma model through mast cells
JOURNAL OF ALLERGY AND CLINICAL IMMUNOLOGY
2018; 142 (5): 1618-+
View details for DOI 10.1016/j.jaci.2018.04.001
View details for Web of Science ID 000449429800023
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Isotype-specific agglutination-PCR (ISAP): Asensitive and multiplex method for measuring allergen-specific IgE.
The Journal of allergy and clinical immunology
2018; 141 (5): 1901
View details for PubMedID 29248495
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Isotype-specific agglutination-PCR (ISAP): A sensitive and multiplex method for measuring allergen-specific IgE
JOURNAL OF ALLERGY AND CLINICAL IMMUNOLOGY
2018; 141 (5): 1901-+
View details for DOI 10.1016/j.jaci.2017.11.021
View details for Web of Science ID 000432148200038
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Epigenetic Changes in Immune Cells Following Successful Desensitization with Multi-Food Allergen Oral Immunotherapy
SPRINGER/PLENUM PUBLISHERS. 2018: 358–59
View details for Web of Science ID 000431311600075
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Mast cells as sources of cytokines, chemokines, and growth factors
IMMUNOLOGICAL REVIEWS
2018; 282 (1): 121–50
Abstract
Mast cells are hematopoietic cells that reside in virtually all vascularized tissues and that represent potential sources of a wide variety of biologically active secreted products, including diverse cytokines and growth factors. There is strong evidence for important non-redundant roles of mast cells in many types of innate or adaptive immune responses, including making important contributions to immediate and chronic IgE-associated allergic disorders and enhancing host resistance to certain venoms and parasites. However, mast cells have been proposed to influence many other biological processes, including responses to bacteria and virus, angiogenesis, wound healing, fibrosis, autoimmune and metabolic disorders, and cancer. The potential functions of mast cells in many of these settings is thought to reflect their ability to secrete, upon appropriate activation by a range of immune or non-immune stimuli, a broad spectrum of cytokines (including many chemokines) and growth factors, with potential autocrine, paracrine, local, and systemic effects. In this review, we summarize the evidence indicating which cytokines and growth factors can be produced by various populations of rodent and human mast cells in response to particular immune or non-immune stimuli, and comment on the proven or potential roles of such mast cell products in health and disease.
View details for PubMedID 29431212
View details for PubMedCentralID PMC5813811
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Thirdhand smoke component can exacerbate a mouse asthma model through mast cells.
The Journal of allergy and clinical immunology
2018
Abstract
Thirdhand smoke (THS) represents the accumulation of secondhand smoke on indoor surfaces and in dust, which, over time, can become more toxic than secondhand smoke. Although it is well known that children of smokers are at increased risk for asthma or asthma exacerbation if the disease is already present, how exposure to THS can influence the development or exacerbation of asthma remains unknown.We investigated whether epicutaneous exposure to an important component of THS, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), can influence asthma pathology in a mouse model elicited by means of repeated intranasal challenge with cockroach antigen (CRA).Wild-type mice, α7 nicotinic acetylcholine receptor (nAChR)- or mast cell (MC)-deficient mice, and mice with MCs that lacked α7 nAChRs or were the host's sole source of α7 nAChRs were subjected to epicutaneous NNK exposure, intranasal CRA challenge, or both, and the severity of features of asthma pathology, including airway hyperreactivity, airway inflammation, and airway remodeling, was assessed.We found that α7 nAChRs were required to observe adverse effects of epicutaneous NNK exposure on multiple features of CRA-induced asthma pathology. Moreover, MC expression of α7 nAChRs contributed significantly to the ability of epicutaneous NNK exposure to exacerbate airway hyperreactivity to methacholine, airway inflammation, and airway remodeling in this model.Our results show that skin exposure to NNK, a component of THS, can exacerbate multiple features of a CRA-induced model of asthma in mice and define MCs as key contributors to these adverse effects of NNK.
View details for PubMedID 29678746
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Targeting of Immune Cells by Dual TLR2/7 Ligands Suppresses Features of Allergic Th2 Immune Responses in Mice.
Journal of immunology research
2017; 2017: 7983217
Abstract
TLR ligands can promote Th1-biased immune responses, mimicking potent stimuli of viruses and bacteria.To investigate the adjuvant properties of dual TLR2/7 ligands compared to those of the mixture of both single ligands.Dual TLR2/7 ligands: CL401, CL413, and CL531, including CL264 (TLR7-ligand) and Pam2CysK4 (TLR2-ligand), were used. Immune-modulatory capacity of the dual ligands with the individual ligands alone or as a mixture in mouse BMmDCs, BMmDC:TC cocultures, or BMCMCs was compared and assessed in naïve mice and in a mouse model of OVA-induced intestinal allergy.CL413 and CL531 induced BMmDC-derived IL-10 secretion, suppressed rOVA-induced IL-5 secretion from OVA-specific DO11.10 CD4+ TCs, and induced proinflammatory cytokine secretion in vivo. In contrast, CL401 induced considerably less IL-10 secretion and led to IL-17A production in BMmDC:TC cocultures, but not BMCMC IL-6 secretion, or IL-6 or TNF-α production in vivo. No immune-modulating effects were observed with single ligands. All dual TLR2/7 ligands suppressed DNP-induced IgE-and-Ag-specific mast cell degranulation. Compared to vaccination with OVA, vaccination with the mixture CL531 and OVA, significantly suppressed OVA-specific IgE production in the intestinal allergy model.Based on beneficial immune-modulating properties, CL413 and CL531 may have utility as potential adjuvants for allergy treatment.
View details for DOI 10.1155/2017/7983217
View details for PubMedID 29204451
View details for PubMedCentralID PMC5674512
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The tyrosine kinase inhibitor imatinib mesylate suppresses uric acid crystal-induced acute gouty arthritis in mice
PLOS ONE
2017; 12 (10): e0185704
Abstract
Gouty arthritis is caused by the deposition of monosodium urate (MSU) crystals in joints. Despite many treatment options for gout, there is a substantial need for alternative treatments for patients unresponsive to current therapies. Tyrosine kinase inhibitors have demonstrated therapeutic benefit in experimental models of antibody-dependent arthritis and in rheumatoid arthritis in humans, but to date, the potential effects of such inhibitors on gouty arthritis has not been evaluated. Here we demonstrate that treatment with the tyrosine kinase inhibitor imatinib mesylate (imatinib) can suppress inflammation induced by injection of MSU crystals into subcutaneous air pouches or into the ankle joint of wild type mice. Moreover, imatinib treatment also largely abolished the lower levels of inflammation which developed in IL-1R1-/- or KitW-sh/W-sh mice, indicating that this drug can inhibit IL-1-independent pathways, as well as mast cell-independent pathways, contributing to pathology in this model. Imatinib treatment not only prevented ankle swelling and synovial inflammation when administered before MSU crystals but also diminished these features when administrated after the injection of MSU crystals, a therapeutic protocol more closely mimicking the clinical situation in which treatment occurs after the development of an acute gout flare. Finally, we also assessed the efficiency of local intra-articular injections of imatinib-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles in this model of acute gout. Treatment with low doses of this long-acting imatinib:PLGA formulation was able to reduce ankle swelling in a therapeutic protocol. Altogether, these results raise the possibility that tyrosine kinase inhibitors might have utility in the treatment of acute gout in humans.
View details for PubMedID 28982129
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A new fluorescent-avidin-based method for quantifying basophil activation in whole blood
JOURNAL OF ALLERGY AND CLINICAL IMMUNOLOGY
2017; 140 (4): 1202-+
View details for PubMedID 28606590
View details for PubMedCentralID PMC5632583
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Imaging protective mast cells in living mice during severe contact hypersensitivity.
JCI insight
2017; 2 (9)
Abstract
Contact hypersensitivity (CHS) is a common skin disease induced by epicutaneous sensitization to haptens. Conflicting results have been obtained regarding pathogenic versus protective roles of mast cells (MCs) in CHS, and this has been attributed in part to the limitations of certain models for studying MC functions in vivo. Here we describe a fluorescent imaging approach that enables in vivo selective labeling and tracking of MC secretory granules by real-time intravital 2-photon microscopy in living mice, and permits the identification of such MCs as a potential source of cytokines in different disease models. We show using this method that dermal MCs release their granules progressively into the surrounding microenvironment, but also represent an initial source of the antiinflammatory cytokine IL-10, during the early phase of severe CHS reactions. Finally, using 3 different types of MC-deficient mice, as well as mice in which IL-10 is ablated specifically in MCs, we show that IL-10 production by MCs can significantly limit the inflammation and tissue pathology observed in severe CHS reactions.
View details for DOI 10.1172/jci.insight.92900
View details for PubMedID 28469089
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Assessing basophil activation by using flow cytometry and mass cytometry in blood stored 24 hours before analysis
JOURNAL OF ALLERGY AND CLINICAL IMMUNOLOGY
2017; 139 (3): 889-?
Abstract
Basophil activation tests (BATs) have promise for research and for clinical monitoring of patients with allergies. However, BAT protocols vary in blood anticoagulant used and temperature and time of storage before testing, complicating comparisons of results from various studies.We attempted to establish a BAT protocol that would permit analysis of blood within 24 hours of obtaining the sample.Blood from 46 healthy donors and 120 patients with peanut allergy was collected into EDTA or heparin tubes, and samples were stored at 4°C or room temperature for 4 or 24 hours before performing BATs.Stimulation with anti-IgE or IL-3 resulted in strong upregulation of basophil CD203c in samples collected in EDTA or heparin, stored at 4°C, and analyzed 24 hours after sample collection. However, a CD63(hi) population of basophils was not observed in any conditions in EDTA-treated samples unless exogenous calcium/magnesium was added at the time of anti-IgE stimulation. By contrast, blood samples collected in heparin tubes were adequate for quantification of upregulation of basophil CD203c and identification of a population of CD63(hi) basophils, irrespective of whether the specimens were analyzed by means of conventional flow cytometry or cytometry by time-of-flight mass spectrometry, and such tests could be performed after blood was stored for 24 hours at 4°C.BATs to measure upregulation of basophil CD203c and induction of a CD63(hi) basophil population can be conducted with blood obtained in heparin tubes and stored at 4°C for 24 hours.
View details for DOI 10.1016/j.jaci.2016.04.060
View details for Web of Science ID 000397295800022
View details for PubMedCentralID PMC5237629
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Pathways of immediate hypothermia and leukocyte infiltration in an adjuvant-free mouse model of anaphylaxis
JOURNAL OF ALLERGY AND CLINICAL IMMUNOLOGY
2017; 139 (2): 584-?
Abstract
Conflicting results have been obtained regarding the roles of Fc receptors and effector cells in models of active systemic anaphylaxis (ASA). In part, this might reflect the choice of adjuvant used during sensitization because various adjuvants might differentially influence the production of particular antibody isotypes.We developed an "adjuvant-free" mouse model of ASA and assessed the contributions of components of the "classical" and "alternative" pathways in this model.Mice were sensitized intraperitoneally with ovalbumin at weekly intervals for 6 weeks and challenged intraperitoneally with ovalbumin 2 weeks later.Wild-type animals had immediate hypothermia and late-phase intraperitoneal inflammation in this model. These features were reduced in mice lacking the IgE receptor FcεRI, the IgG receptor FcγRIII or the common γ-chain FcRγ. FcγRIV blockade resulted in a partial reduction of inflammation without any effect on hypothermia. Depletion of monocytes/macrophages with clodronate liposomes significantly reduced the hypothermia response. By contrast, depletion of neutrophils or basophils had no significant effects in this ASA model. Both the hypothermia and inflammation were dependent on platelet-activating factor and histamine and were reduced in 2 types of mast cell (MC)-deficient mice. Finally, engraftment of MC-deficient mice with bone marrow-derived cultured MCs significantly exacerbated the hypothermia response and restored inflammation to levels similar to those observed in wild-type mice.Components of the classical and alternative pathways contribute to anaphylaxis in this adjuvant-free model, with key roles for MCs and monocytes/macrophages.
View details for DOI 10.1016/j.jaci.2016.05.047
View details for Web of Science ID 000397002400024
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Assessing basophil activation by flow cytometry and mass cytometry in blood stored 24 hours before analysis
MOSBY-ELSEVIER. 2017: AB124
View details for DOI 10.1016/j.jaci.2016.12.402
View details for Web of Science ID 000401699800293
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Targeting of Immune Cells by Dual TLR2/7 Ligands Suppresses Features of Allergic Th2 Immune Responses in Mice
JOURNAL OF IMMUNOLOGY RESEARCH
2017
View details for DOI 10.1155/2017/7983217
View details for Web of Science ID 000414576700001
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Mast Cells and IgE can Enhance Survival During Innate and Acquired Host Responses to Venoms.
Transactions of the American Clinical and Climatological Association
2017; 128: 193–221
Abstract
Mast cells and immunoglobulin E (IgE) antibodies are thought to promote health by contributing to host responses to certain parasites, but other beneficial functions have remained obscure. Venoms provoke innate inflammatory responses and pathology reflecting the activities of the contained toxins. Venoms also can induce allergic sensitization and development of venom-specific IgE antibodies, which can predispose some subjects to exhibit anaphylaxis upon subsequent exposure to the relevant venom. We found that innate functions of mast cells, including degradation of venom toxins by mast cell-derived proteases, enhanced survival in mice injected with venoms from the honeybee, two species of scorpion, three species of poisonous snakes, or the Gila monster. We also found that mice injected with sub-lethal amounts of honeybee or Russell's viper venom exhibited enhanced survival after subsequent challenge with potentially lethal amounts of that venom, and that IgE antibodies, FcepsilonRI, and probably mast cells contributed to such acquired resistance.
View details for PubMedID 28790503
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A TNFRSF14-Fc epsilon RI-mast cell pathway contributes to development of multiple features of asthma pathology in mice
NATURE COMMUNICATIONS
2016; 7
Abstract
Asthma has multiple features, including airway hyperreactivity, inflammation and remodelling. The TNF superfamily member TNFSF14 (LIGHT), via interactions with the receptor TNFRSF14 (HVEM), can support TH2 cell generation and longevity and promote airway remodelling in mouse models of asthma, but the mechanisms by which TNFSF14 functions in this setting are incompletely understood. Here we find that mouse and human mast cells (MCs) express TNFRSF14 and that TNFSF14:TNFRSF14 interactions can enhance IgE-mediated MC signalling and mediator production. In mouse models of asthma, TNFRSF14 blockade with a neutralizing antibody administered after antigen sensitization, or genetic deletion of Tnfrsf14, diminishes plasma levels of antigen-specific IgG1 and IgE antibodies, airway hyperreactivity, airway inflammation and airway remodelling. Finally, by analysing two types of genetically MC-deficient mice after engrafting MCs that either do or do not express TNFRSF14, we show that TNFRSF14 expression on MCs significantly contributes to the development of multiple features of asthma pathology.
View details for DOI 10.1038/ncomms13696
View details for Web of Science ID 000389853400001
View details for PubMedID 27982078
View details for PubMedCentralID PMC5171877
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Guanine nucleotide exchange factor RABGEF1 regulates keratinocyte-intrinsic signaling to maintain skin homeostasis.
journal of clinical investigation
2016
Abstract
Epidermal keratinocytes form a structural and immune barrier that is essential for skin homeostasis. However, the mechanisms that regulate epidermal barrier function are incompletely understood. Here we have found that keratinocyte-specific deletion of the gene encoding RAB guanine nucleotide exchange factor 1 (RABGEF1, also known as RABEX-5) severely impairs epidermal barrier function in mice and induces an allergic cutaneous and systemic phenotype. RABGEF1-deficient keratinocytes exhibited aberrant activation of the intrinsic IL-1R/MYD88/NF-κB signaling pathway and MYD88-dependent abnormalities in expression of structural proteins that contribute to skin barrier function. Moreover, ablation of MYD88 signaling in RABGEF1-deficient keratinocytes or deletion of Il1r1 restored skin homeostasis and prevented development of skin inflammation. We further demonstrated that epidermal RABGEF1 expression is reduced in skin lesions of humans diagnosed with either atopic dermatitis or allergic contact dermatitis as well as in an inducible mouse model of allergic dermatitis. Our findings reveal a key role for RABGEF1 in dampening keratinocyte-intrinsic MYD88 signaling and sustaining epidermal barrier function in mice, and suggest that dysregulation of RABGEF1 expression may contribute to epidermal barrier dysfunction in allergic skin disorders in mice and humans. Thus, RABGEF1-mediated regulation of IL-1R/MYD88 signaling might represent a potential therapeutic target.
View details for DOI 10.1172/JCI86359
View details for PubMedID 27820702
View details for PubMedCentralID PMC5127679
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Different activation signals induce distinct mast cell degranulation strategies
JOURNAL OF CLINICAL INVESTIGATION
2016; 126 (10): 3981-3998
Abstract
Mast cells (MCs) influence intercellular communication during inflammation by secreting cytoplasmic granules that contain diverse mediators. Here, we have demonstrated that MCs decode different activation stimuli into spatially and temporally distinct patterns of granule secretion. Certain signals, including substance P, the complement anaphylatoxins C3a and C5a, and endothelin 1, induced human MCs rapidly to secrete small and relatively spherical granule structures, a pattern consistent with the secretion of individual granules. Conversely, activating MCs with anti-IgE increased the time partition between signaling and secretion, which was associated with a period of sustained elevation of intracellular calcium and formation of larger and more heterogeneously shaped granule structures that underwent prolonged exteriorization. Pharmacological inhibition of IKK-β during IgE-dependent stimulation strongly reduced the time partition between signaling and secretion, inhibited SNAP23/STX4 complex formation, and switched the degranulation pattern into one that resembled degranulation induced by substance P. IgE-dependent and substance P-dependent activation in vivo also induced different patterns of mouse MC degranulation that were associated with distinct local and systemic pathophysiological responses. These findings show that cytoplasmic granule secretion from MCs that occurs in response to different activating stimuli can exhibit distinct dynamics and features that are associated with distinct patterns of MC-dependent inflammation.
View details for DOI 10.1172/JCI85538
View details for Web of Science ID 000384703300034
View details for PubMedID 27643442
View details for PubMedCentralID PMC5096814
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IgE and mast cells in host defense against parasites and venoms.
Seminars in immunopathology
2016; 38 (5): 581-603
Abstract
IgE-dependent mast cell activation is a major effector mechanism underlying the pathology associated with allergic disorders. The most dramatic of these IgE-associated disorders is the fatal anaphylaxis which can occur in some people who have developed IgE antibodies to otherwise innocuous antigens, such as those contained in certain foods and medicines. Why would such a highly "maladaptive" immune response develop in evolution and be retained to the present day? Host defense against parasites has long been considered the only beneficial function that might be conferred by IgE and mast cells. However, recent studies have provided evidence that, in addition to participating in host resistance to certain parasites, mast cells and IgE are critical components of innate (mast cells) and adaptive (mast cells and IgE) immune responses that can enhance host defense against the toxicity of certain arthropod and animal venoms, including enhancing the survival of mice injected with such venoms. Yet, in some people, developing IgE antibodies to insect or snake venoms puts them at risk for having a potentially fatal anaphylactic reaction upon subsequent exposure to such venoms. Delineating the mechanisms underlying beneficial versus detrimental innate and adaptive immune responses associated with mast cell activation and IgE is likely to enhance our ability to identify potential therapeutic targets in such settings, not only for reducing the pathology associated with allergic disorders but perhaps also for enhancing immune protection against pathogens and animal venoms.
View details for DOI 10.1007/s00281-016-0565-1
View details for PubMedID 27225312
View details for PubMedCentralID PMC5010491
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Pathways of immediate hypothermia and leukocyte infiltration in an adjuvant-free mouse model of anaphylaxis.
journal of allergy and clinical immunology
2016
Abstract
Conflicting results have been obtained regarding the roles of Fc receptors and effector cells in models of active systemic anaphylaxis (ASA). In part, this might reflect the choice of adjuvant used during sensitization because various adjuvants might differentially influence the production of particular antibody isotypes.We developed an "adjuvant-free" mouse model of ASA and assessed the contributions of components of the "classical" and "alternative" pathways in this model.Mice were sensitized intraperitoneally with ovalbumin at weekly intervals for 6 weeks and challenged intraperitoneally with ovalbumin 2 weeks later.Wild-type animals had immediate hypothermia and late-phase intraperitoneal inflammation in this model. These features were reduced in mice lacking the IgE receptor FcεRI, the IgG receptor FcγRIII or the common γ-chain FcRγ. FcγRIV blockade resulted in a partial reduction of inflammation without any effect on hypothermia. Depletion of monocytes/macrophages with clodronate liposomes significantly reduced the hypothermia response. By contrast, depletion of neutrophils or basophils had no significant effects in this ASA model. Both the hypothermia and inflammation were dependent on platelet-activating factor and histamine and were reduced in 2 types of mast cell (MC)-deficient mice. Finally, engraftment of MC-deficient mice with bone marrow-derived cultured MCs significantly exacerbated the hypothermia response and restored inflammation to levels similar to those observed in wild-type mice.Components of the classical and alternative pathways contribute to anaphylaxis in this adjuvant-free model, with key roles for MCs and monocytes/macrophages.
View details for DOI 10.1016/j.jaci.2016.05.047
View details for PubMedID 27555460
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Mast cells and IgE in defense against venoms: Possible "good side" of allergy?
ALLERGOLOGY INTERNATIONAL
2016; 65 (1): 3-15
Abstract
Physicians think of mast cells and IgE primarily in the context of allergic disorders, including fatal anaphylaxis. This 'bad side' of mast cells and IgE is so well accepted that it can be difficult to think of them in other contexts, particularly those in which they may have beneficial functions. However, there is evidence that mast cells and IgE, as well as basophils (circulating granulocytes whose functions partially overlap with those of mast cells), can contribute to host defense as components of adaptive type 2 immune responses to helminths, ticks and certain other parasites. Accordingly, allergies often are conceptualized as "misdirected" type 2 immune responses, in which IgE antibodies are produced against any of a diverse group of apparently harmless antigens, as well as against components of animal venoms. Indeed, certain unfortunate patients who have become sensitized to venoms develop severe IgE-associated allergic reactions, including fatal anaphylaxis, upon subsequent venom exposure. In this review, we will describe evidence that mast cells can enhance innate resistance to reptile or arthropod venoms during a first exposure to such venoms. We also will discuss findings indicating that, in mice which survive an initial encounter with venom, acquired type 2 immune responses, IgE antibodies, the high affinity IgE receptor (FcɛRI), and mast cells can contribute to acquired resistance to the lethal effects of both honeybee venom and Russell's viper venom. These findings support the hypothesis that mast cells and IgE can help protect the host against venoms and perhaps other noxious substances.
View details for DOI 10.1016/j.alit.2015.09.002
View details for Web of Science ID 000367238600002
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IgE antibodies, Fc epsilon RI alpha, and IgE-mediated local anaphylaxis can limit snake venom toxicity
JOURNAL OF ALLERGY AND CLINICAL IMMUNOLOGY
2016; 137 (1): 246-?
Abstract
Type 2 cytokine-related immune responses associated with development of antigen-specific IgE antibodies can contribute to pathology in patients with allergic diseases and to fatal anaphylaxis. However, recent findings in mice indicate that IgE also can enhance defense against honeybee venom.We tested whether IgE antibodies, IgE-dependent effector mechanisms, and a local anaphylactic reaction to an unrelated antigen can enhance defense against Russell viper venom (RVV) and determined whether such responses can be influenced by immunization protocol or mouse strain.We compared the resistance of RVV-immunized wild-type, IgE-deficient, and Fcer1a-deficient mice after injection of a potentially lethal dose of RVV.A single prior exposure to RVV enhanced the ability of wild-type mice, but not mice lacking IgE or functional FcεRI, to survive challenge with a potentially lethal amount of RVV. Moreover, IgE-dependent local passive cutaneous anaphylaxis in response to challenge with an antigen not naturally present in RVV significantly enhanced resistance to the venom. Finally, we observed different effects on resistance to RVV or honeybee venom in BALB/c versus C57BL/6 mice that had received a second exposure to that venom before challenge with a high dose of that venom.These observations illustrate the potential benefit of IgE-dependent effector mechanisms in acquired host defense against venoms. The extent to which type 2 immune responses against venoms can decrease pathology associated with envenomation seems to be influenced by the type of venom, the frequency of venom exposure, and the genetic background of the host.
View details for DOI 10.1016/j.jaci.2015.08.005
View details for Web of Science ID 000367724300016
View details for PubMedCentralID PMC4715494
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Testing the 'toxin hypothesis of allergy': mast cells, IgE, and innate and acquired immune responses to venoms
CURRENT OPINION IN IMMUNOLOGY
2015; 36: 80-87
Abstract
Work in mice indicates that innate functions of mast cells, particularly degradation of venom toxins by mast cell-derived proteases, can enhance resistance to certain arthropod or reptile venoms. Recent reports indicate that acquired Th2 immune responses associated with the production of IgE antibodies, induced by Russell's viper venom or honeybee venom, or by a component of honeybee venom, bee venom phospholipase 2 (bvPLA2), can increase the resistance of mice to challenge with potentially lethal doses of either of the venoms or bvPLA2. These findings support the conclusion that, in contrast to the detrimental effects associated with allergic type 2 (Th2) immune responses, mast cells and IgE-dependent immune responses to venoms can contribute to innate and adaptive resistance to venom-induced pathology and mortality.
View details for DOI 10.1016/j.coi.2015.07.001
View details for Web of Science ID 000363070000014
View details for PubMedID 26210895
View details for PubMedCentralID PMC4593748
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Approaches for analyzing the roles of mast cells and their proteases in vivo.
Advances in immunology
2015; 126: 45-127
Abstract
The roles of mast cells in health and disease remain incompletely understood. While the evidence that mast cells are critical effector cells in IgE-dependent anaphylaxis and other acute IgE-mediated allergic reactions seems unassailable, studies employing various mice deficient in mast cells or mast cell-associated proteases have yielded divergent conclusions about the roles of mast cells or their proteases in certain other immunological responses. Such "controversial" results call into question the relative utility of various older versus newer approaches to ascertain the roles of mast cells and mast cell proteases in vivo. This review discusses how both older and more recent mouse models have been used to investigate the functions of mast cells and their proteases in health and disease. We particularly focus on settings in which divergent conclusions about the importance of mast cells and their proteases have been supported by studies that employed different models of mast cell or mast cell protease deficiency. We think that two major conclusions can be drawn from such findings: (1) no matter which models of mast cell or mast cell protease deficiency one employs, the conclusions drawn from the experiments always should take into account the potential limitations of the models (particularly abnormalities affecting cell types other than mast cells) and (2) even when analyzing a biological response using a single model of mast cell or mast cell protease deficiency, details of experimental design are critical in efforts to define those conditions under which important contributions of mast cells or their proteases can be identified.
View details for DOI 10.1016/bs.ai.2014.11.002
View details for PubMedID 25727288
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RabGEF1/Rabex-5 Regulates TrkA-Mediated Neurite Outgrowth and NMDA-Induced Signaling Activation in NGF-Differentiated PC12 Cells.
PloS one
2015; 10 (11): e0142935
Abstract
Nerve growth factor (NGF) binds to its cognate receptor TrkA and induces neuronal differentiation by activating distinct downstream signal transduction events. RabGEF1 (also known as Rabex-5) is a guanine nucleotide exchange factor for Rab5, which regulates early endosome fusion and vesicular trafficking in endocytic pathways. Here, we used the antisense (AS) expression approach to induce an NGF-dependent sustained knockdown of RabGEF1 protein expression in stable PC12 transfectants. We show that RabGEF1 is a negative regulator of NGF-induced neurite outgrowth and modulates other cellular and signaling processes that are activated by the interaction of NGF with TrkA receptors, such as cell cycle progression, cessation of proliferation, and activation of NGF-mediated downstream signaling responses. Moreover, RabGEF1 can bind to Rac1, and the activation of Rac1 upon NGF treatment is significantly enhanced in AS transfectants, suggesting that RabGEF1 is a negative regulator of NGF-induced Rac1 activation in PC12 cells. Furthermore, we show that RabGEF1 can also interact with NMDA receptors by binding to the NR2B subunit and its associated binding partner SynGAP, and negatively regulates activation of nitric oxide synthase activity induced by NMDA receptor stimulation in NGF-differentiated PC12 cells. Our data suggest that RabGEF1 is a negative regulator of TrkA-dependent neuronal differentiation and of NMDA receptor-mediated signaling activation in NGF-differentiated PC12 cells.
View details for DOI 10.1371/journal.pone.0142935
View details for PubMedID 26588713
View details for PubMedCentralID PMC4654474
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Analyzing the Functions of Mast Cells In Vivo Using 'Mast Cell Knock-in' Mice.
Journal of visualized experiments : JoVE
2015: e52753
Abstract
Mast cells (MCs) are hematopoietic cells which reside in various tissues, and are especially abundant at sites exposed to the external environment, such as skin, airways and gastrointestinal tract. Best known for their detrimental role in IgE-dependent allergic reactions, MCs have also emerged as important players in host defense against venom and invading bacteria and parasites. MC phenotype and function can be influenced by microenvironmental factors that may differ according to anatomic location and/or based on the type or stage of development of immune responses. For this reason, we and others have favored in vivo approaches over in vitro methods to gain insight into MC functions. Here, we describe methods for the generation of mouse bone marrow-derived cultured MCs (BMCMCs), their adoptive transfer into genetically MC-deficient mice, and the analysis of the numbers and distribution of adoptively transferred MCs at different anatomical sites. This method, named the 'mast cell knock-in' approach, has been extensively used over the past 30 years to assess the functions of MCs and MC-derived products in vivo. We discuss the advantages and limitations of this method, in light of alternative approaches that have been developed in recent years.
View details for DOI 10.3791/52753
View details for PubMedID 26068439
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Analyzing the Functions of Mast Cells In Vivo Using 'Mast Cell Knock-in' Mice.
Journal of visualized experiments : JoVE
2015
Abstract
Mast cells (MCs) are hematopoietic cells which reside in various tissues, and are especially abundant at sites exposed to the external environment, such as skin, airways and gastrointestinal tract. Best known for their detrimental role in IgE-dependent allergic reactions, MCs have also emerged as important players in host defense against venom and invading bacteria and parasites. MC phenotype and function can be influenced by microenvironmental factors that may differ according to anatomic location and/or based on the type or stage of development of immune responses. For this reason, we and others have favored in vivo approaches over in vitro methods to gain insight into MC functions. Here, we describe methods for the generation of mouse bone marrow-derived cultured MCs (BMCMCs), their adoptive transfer into genetically MC-deficient mice, and the analysis of the numbers and distribution of adoptively transferred MCs at different anatomical sites. This method, named the 'mast cell knock-in' approach, has been extensively used over the past 30 years to assess the functions of MCs and MC-derived products in vivo. We discuss the advantages and limitations of this method, in light of alternative approaches that have been developed in recent years.
View details for DOI 10.3791/52753
View details for PubMedID 26068439
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Contribution of Mast Cell-Derived Interleukin-1 beta to Uric Acid Crystal-Induced Acute Arthritis in Mice
ARTHRITIS & RHEUMATOLOGY
2014; 66 (10): 2881-2891
Abstract
Gouty arthritis is caused by the precipitation of monosodium urate monohydrate (MSU) crystals in the joints. While it has been reported that mast cells (MCs) infiltrate gouty tophi, little is known about the actual roles of MCs during acute attacks of gout. This study was undertaken to assess the role of MCs in a mouse model of MSU crystal-induced acute arthritis.We assessed the effects of intraarticular (IA) injection of MSU crystals in various strains of mice with constitutive or inducible MC deficiency or in mice lacking interleukin-1β (IL-1β) or other elements of innate immunity. We also assessed the response to IA injection of MSU crystals in genetically MC-deficient mice after IA engraftment of wild-type or IL-1β(-/-) bone marrow-derived cultured MCs.MCs were found to augment acute tissue swelling following IA injection of MSU crystals in mice. IL-1β production by MCs contributed importantly to MSU crystal-induced tissue swelling, particularly during its early stages. Selective depletion of synovial MCs was able to diminish MSU crystal-induced acute inflammation in the joints.Our findings identify a previously unrecognized role of MCs and MC-derived IL-1β in the early stages of MSU crystal-induced acute arthritis in mice.
View details for DOI 10.1002/art.38747
View details for Web of Science ID 000342744300026
View details for PubMedCentralID PMC4443497
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Evidence that Meningeal Mast Cells Can Worsen Stroke Pathology in Mice
AMERICAN JOURNAL OF PATHOLOGY
2014; 184 (9): 2493-2504
Abstract
Stroke is the leading cause of adult disability and the fourth most common cause of death in the United States. Inflammation is thought to play an important role in stroke pathology, but the factors that promote inflammation in this setting remain to be fully defined. An understudied but important factor is the role of meningeal-located immune cells in modulating brain pathology. Although different immune cells traffic through meningeal vessels en route to the brain, mature mast cells do not circulate but are resident in the meninges. With the use of genetic and cell transfer approaches in mice, we identified evidence that meningeal mast cells can importantly contribute to the key features of stroke pathology, including infiltration of granulocytes and activated macrophages, brain swelling, and infarct size. We also obtained evidence that two mast cell-derived products, interleukin-6 and, to a lesser extent, chemokine (C-C motif) ligand 7, can contribute to stroke pathology. These findings indicate a novel role for mast cells in the meninges, the membranes that envelop the brain, as potential gatekeepers for modulating brain inflammation and pathology after stroke.
View details for DOI 10.1016/j.ajpath.2014.06.003
View details for PubMedID 25134760
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Peanut oral immunotherapy results in increased antigen-induced regulatory T-cell function and hypomethylation of forkhead box protein 3 (FOXP3).
journal of allergy and clinical immunology
2014; 133 (2): 500-510
Abstract
The mechanisms contributing to clinical immune tolerance remain incompletely understood. This study provides evidence for specific immune mechanisms that are associated with a model of operationally defined clinical tolerance.Our overall objective was to study laboratory changes associated with clinical immune tolerance in antigen-induced T cells, basophils, and antibodies in subjects undergoing oral immunotherapy (OIT) for peanut allergy.In a phase 1 single-site study, we studied participants (n = 23) undergoing peanut OIT and compared them with age-matched allergic control subjects (n = 20) undergoing standard of care (abstaining from peanut) for 24 months. Participants were operationally defined as clinically immune tolerant (IT) if they had no detectable allergic reactions to a peanut oral food challenge after 3 months of therapy withdrawal (IT, n = 7), whereas those who had an allergic reaction were categorized as nontolerant (NT; n = 13).Antibody and basophil activation measurements did not statistically differentiate between NT versus IT participants. However, T-cell function and demethylation of forkhead box protein 3 (FOXP3) CpG sites in antigen-induced regulatory T cells were significantly different between IT versus NT participants. When IT participants were withdrawn from peanut therapy for an additional 3 months (total of 6 months), only 3 participants remained classified as IT participants, and 4 participants regained sensitivity along with increased methylation of FOXP3 CpG sites in antigen-induced regulatory T cells.In summary, modifications at the DNA level of antigen-induced T-cell subsets might be predictive of a state of operationally defined clinical immune tolerance during peanut OIT.
View details for DOI 10.1016/j.jaci.2013.12.1037
View details for PubMedID 24636474
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A Beneficial Role for Immunoglobulin E in Host Defense against Honeybee Venom.
Immunity
2013; 39 (5): 963-975
Abstract
Allergies are widely considered to be misdirected type 2 immune responses, in which immunoglobulin E (IgE) antibodies are produced against any of a broad range of seemingly harmless antigens. However, components of insect venoms also can sensitize individuals to develop severe IgE-associated allergic reactions, including fatal anaphylaxis, upon subsequent venom exposure. We found that mice injected with amounts of honeybee venom similar to that which could be delivered in one or two stings developed a specific type 2 immune response that increased their resistance to subsequent challenge with potentially lethal amounts of the venom. Our data indicate that IgE antibodies and the high affinity IgE receptor, FcεRI, were essential for such acquired resistance to honeybee venom. The evidence that IgE-dependent immune responses against venom can enhance survival in mice supports the hypothesis that IgE, which also contributes to allergic disorders, has an important function in protection of the host against noxious substances.
View details for DOI 10.1016/j.immuni.2013.10.005
View details for PubMedID 24210352
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Mast cells: potential positive and negative roles in tumor biology.
Cancer immunology research
2013; 1 (5): 269-279
Abstract
Mast cells are immune cells that reside in virtually all vascularized tissues. Upon activation by diverse mechanisms, mast cells can secrete a broad array of biologically active products that either are stored in the cytoplasmic granules of the cells (e.g., histamine, heparin, various proteases) or are produced de novo upon cell stimulation (e.g., prostaglandins, leukotrienes, cytokines, chemokines, and growth factors). Mast cells are best known for their effector functions during anaphylaxis and acute IgE-associated allergic reactions, but they also have been implicated in a wide variety of processes that maintain health or contribute to disease. There has been particular interest in the possible roles of mast cells in tumor biology. In vitro studies have shown that mast cells have the potential to influence many aspects of tumor biology, including tumor development, tumor-induced angiogenesis, and tissue remodeling, and the shaping of adaptive immune responses to tumors. Yet, the actual contributions of mast cells to tumor biology in vivo remain controversial. Here, we review some basic features of mast cell biology with a special emphasis on those relevant to their potential roles in tumors. We discuss how using in vivo tumor models in combination with models in which mast cell function can be modulated has implicated mast cells in the regulation of host responses to tumors. Finally, we summarize data from studies of human tumors that suggest either beneficial or detrimental roles for mast cells in tumors.
View details for DOI 10.1158/2326-6066.CIR-13-0119
View details for PubMedID 24777963
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Rapid desensitization induces internalization of antigen-specific IgE on mouse mast cells.
journal of allergy and clinical immunology
2013; 132 (4): 922-32 e1 16
Abstract
Rapid desensitization transiently prevents severe allergic reactions, allowing administration of life-saving therapies in previously sensitized patients. However, the mechanisms underlying successful rapid desensitization are not fully understood.We sought to investigate whether the mast cell (MC) is an important target of rapid desensitization in mice sensitized to exhibit IgE-dependent passive systemic anaphylaxis in vivo and to investigate the antigen specificity and underlying mechanisms of rapid desensitization in our mouse model.C57BL/6 mice (in vivo) or primary isolated C57BL/6 mouse peritoneal mast cells (PMCs; in vitro) were passively sensitized with antigen-specific anti-2,4-dinitrophenyl IgE, anti-ovalbumin IgE, or both. MCs were exposed over a short period of time to increasing amounts of antigen (2,4-dinitrophenyl-human serum albumin or ovalbumin) in the presence of extracellular calcium in vitro or by means of intravenous administration to sensitized mice in vivo before challenging the mice with or exposing the PMCs to optimal amounts of specific or irrelevant antigen.Rapidly exposing mice or PMCs to progressively increasing amounts of specific antigen inhibited the development of antigen-induced hypothermia in sensitized mice in vivo and inhibited antigen-induced PMC degranulation and prostaglandin D2 synthesis in vitro. Such MC hyporesponsiveness was induced antigen-specifically and was associated with a significant reduction in antigen-specific IgE levels on MC surfaces.Rapidly exposing MCs to progressively increasing amounts of antigen can both enhance the internalization of antigen-specific IgE on the MC surface and also desensitize these cells in an antigen-specific manner in vivo and in vitro.
View details for DOI 10.1016/j.jaci.2013.05.004
View details for PubMedID 23810240
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Rapid desensitization induces internalization of antigen-specific IgE on mouse mast cells.
journal of allergy and clinical immunology
2013; 132 (4): 922-932 e16
Abstract
Rapid desensitization transiently prevents severe allergic reactions, allowing administration of life-saving therapies in previously sensitized patients. However, the mechanisms underlying successful rapid desensitization are not fully understood.We sought to investigate whether the mast cell (MC) is an important target of rapid desensitization in mice sensitized to exhibit IgE-dependent passive systemic anaphylaxis in vivo and to investigate the antigen specificity and underlying mechanisms of rapid desensitization in our mouse model.C57BL/6 mice (in vivo) or primary isolated C57BL/6 mouse peritoneal mast cells (PMCs; in vitro) were passively sensitized with antigen-specific anti-2,4-dinitrophenyl IgE, anti-ovalbumin IgE, or both. MCs were exposed over a short period of time to increasing amounts of antigen (2,4-dinitrophenyl-human serum albumin or ovalbumin) in the presence of extracellular calcium in vitro or by means of intravenous administration to sensitized mice in vivo before challenging the mice with or exposing the PMCs to optimal amounts of specific or irrelevant antigen.Rapidly exposing mice or PMCs to progressively increasing amounts of specific antigen inhibited the development of antigen-induced hypothermia in sensitized mice in vivo and inhibited antigen-induced PMC degranulation and prostaglandin D2 synthesis in vitro. Such MC hyporesponsiveness was induced antigen-specifically and was associated with a significant reduction in antigen-specific IgE levels on MC surfaces.Rapidly exposing MCs to progressively increasing amounts of antigen can both enhance the internalization of antigen-specific IgE on the MC surface and also desensitize these cells in an antigen-specific manner in vivo and in vitro.
View details for DOI 10.1016/j.jaci.2013.05.004
View details for PubMedID 23810240
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Selective ablation of mast cells or basophils reduces peanut-induced anaphylaxis in mice.
journal of allergy and clinical immunology
2013; 132 (4): 881-888 e11
Abstract
Studies with c-kit mutant mast cell (MC)-deficient mice and antibody-mediated depletion of basophils suggest that both MCs and basophils can contribute to peanut-induced anaphylaxis (PIA). However, interpretation of data obtained by using such approaches is complicated because c-kit mutant mice have several phenotypic abnormalities in addition to MC deficiency and because basophil-depleting antibodies can also react with MCs.We analyzed (1) the changes in the features of PIA in mice after the selective and inducible ablation of MCs or basophils and (2) the possible importance of effector cells other than MCs and basophils in the PIA response.Wild-type and various mutant mice were orally sensitized with peanut extract and cholera toxin weekly for 4 weeks and challenged intraperitoneally with peanut extract 2 weeks later.Peanut-challenged, MC-deficient Kit(W-sh/W-sh) mice had reduced immediate hypothermia, as well as a late-phase decrease in body temperature that was abrogated by antibody-mediated depletion of neutrophils. Diphtheria toxin-mediated selective depletion of MCs or basophils in Mcpt5-Cre;iDTR and Mcpt8(DTR) mice, respectively, and treatment of wild-type mice with the basophil-depleting antibody Ba103 significantly reduced peanut-induced hypothermia. Non-c-kit mutant MC- and basophil-deficient Cpa3-Cre;Mcl-1(fl/fl) mice had reduced but still significant responses to peanut.Inducible and selective ablation of MCs or basophils in non-c-kit mutant mice can significantly reduce PIA, but partial responses to peanut can still be observed in the virtual absence of both cell types. The neutrophilia in Kit(W-sh/W-sh) mice might influence the responses of these mice in this PIA model.
View details for DOI 10.1016/j.jaci.2013.06.008
View details for PubMedID 23915716
View details for PubMedCentralID PMC3794715
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Selective ablation of mast cells or basophils reduces peanut-induced anaphylaxis in mice.
journal of allergy and clinical immunology
2013; 132 (4): 881-8 e1 11
Abstract
Studies with c-kit mutant mast cell (MC)-deficient mice and antibody-mediated depletion of basophils suggest that both MCs and basophils can contribute to peanut-induced anaphylaxis (PIA). However, interpretation of data obtained by using such approaches is complicated because c-kit mutant mice have several phenotypic abnormalities in addition to MC deficiency and because basophil-depleting antibodies can also react with MCs.We analyzed (1) the changes in the features of PIA in mice after the selective and inducible ablation of MCs or basophils and (2) the possible importance of effector cells other than MCs and basophils in the PIA response.Wild-type and various mutant mice were orally sensitized with peanut extract and cholera toxin weekly for 4 weeks and challenged intraperitoneally with peanut extract 2 weeks later.Peanut-challenged, MC-deficient Kit(W-sh/W-sh) mice had reduced immediate hypothermia, as well as a late-phase decrease in body temperature that was abrogated by antibody-mediated depletion of neutrophils. Diphtheria toxin-mediated selective depletion of MCs or basophils in Mcpt5-Cre;iDTR and Mcpt8(DTR) mice, respectively, and treatment of wild-type mice with the basophil-depleting antibody Ba103 significantly reduced peanut-induced hypothermia. Non-c-kit mutant MC- and basophil-deficient Cpa3-Cre;Mcl-1(fl/fl) mice had reduced but still significant responses to peanut.Inducible and selective ablation of MCs or basophils in non-c-kit mutant mice can significantly reduce PIA, but partial responses to peanut can still be observed in the virtual absence of both cell types. The neutrophilia in Kit(W-sh/W-sh) mice might influence the responses of these mice in this PIA model.
View details for DOI 10.1016/j.jaci.2013.06.008
View details for PubMedID 23915716
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Mast cell anaphylatoxin receptor expression can enhance IgE-dependent skin inflammation in mice
JOURNAL OF ALLERGY AND CLINICAL IMMUNOLOGY
2013; 131 (2): 541-?
Abstract
Mast cells express receptors for complement anaphylatoxins C3a and C5a (ie, C3a receptor [C3aR] and C5a receptor [C5aR]), and C3a and C5a are generated during various IgE-dependent immediate hypersensitivity reactions in vivo. However, it is not clear to what extent mast cell expression of C3aR or C5aR influences C3a- or C5a-induced cutaneous responses or IgE-dependent mast cell activation and passive cutaneous anaphylaxis (PCA) in vivo.We sought to assess whether mouse skin mast cell expression of C3aR or C5aR influences (1) the cells' responsiveness to intradermal injections of C3a or C5a or (2) the extent of IgE-dependent mast cell degranulation and PCA in vivo.We measured the magnitude of cutaneous responses to intradermal injections of C3a or C5a and the extent of IgE-dependent mast cell degranulation and PCA responses in mice containing mast cells that did or did not express C3aR or C5aR.The majority of the skin swelling induced by means of intradermal injection of C3a or C5a required that mast cells at the site expressed C3aR or C5aR, respectively, and the extent of IgE-dependent degranulation of skin mast cells and IgE-dependent PCA was significantly reduced when mast cells lacked either C3aR or C5aR. IgE-dependent PCA responses associated with local increases in C3a levels occurred in antibody-deficient mice but not in mice deficient in FcɛRIγ.Expression of C3aR and C5aR by skin mast cells contributes importantly to the ability of C3a and C5a to induce skin swelling and can enhance mast cell degranulation and inflammation during IgE-dependent PCA in vivo.
View details for DOI 10.1016/j.jaci.2012.05.009
View details for Web of Science ID 000314661500034
View details for PubMedID 22728083
View details for PubMedCentralID PMC3597773
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Meningeal Mast Cells Can Exacerbate Stroke Pathology In Mice
LIPPINCOTT WILLIAMS & WILKINS. 2013
View details for Web of Science ID 000330540200433
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Evidence that mast cells are not required for healing of splinted cutaneous excisional wounds in mice.
PloS one
2013; 8 (3)
Abstract
Wound healing is a complex biological process involving the interaction of many cell types to replace lost or damaged tissue. Although the biology of wound healing has been extensively investigated, few studies have focused on the role of mast cells. In this study, we investigated the possible role of mast cells in wound healing by analyzing aspects of cutaneous excisional wound healing in three types of genetically mast cell-deficient mice. We found that C57BL/6-Kit(W-sh/W-sh), WBB6F1-Kit(W/W-v), and Cpa3-Cre; Mcl-1(fl/fl) mice re-epithelialized splinted excisional skin wounds at rates very similar to those in the corresponding wild type or control mice. Furthermore, at the time of closure, scars were similar in the genetically mast cell-deficient mice and the corresponding wild type or control mice in both quantity of collagen deposition and maturity of collagen fibers, as evaluated by Masson's Trichrome and Picro-Sirius red staining. These data indicate that mast cells do not play a significant non-redundant role in these features of the healing of splinted full thickness excisional cutaneous wounds in mice.
View details for DOI 10.1371/journal.pone.0059167
View details for PubMedID 23544053
View details for PubMedCentralID PMC3609818
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Evidence questioning cromolyn's effectiveness and selectivity as a 'mast cell stabilizer' in mice
LABORATORY INVESTIGATION
2012; 92 (10): 1472-1482
Abstract
Cromolyn, widely characterized as a 'mast cell stabilizer', has been used in mice to investigate the biological roles of mast cells in vivo. However, it is not clear to what extent cromolyn can either limit the function of mouse mast cells or influence biological processes in mice independently of effects on mast cells. We confirmed that cromolyn (at 10 mg/kg in vivo or 10-100 μM in vitro) can inhibit IgE-dependent mast cell activation in rats in vivo (measuring Evans blue extravasation in passive cutaneous anaphylaxis (PCA) and increases in plasma histamine in passive systemic anaphylaxis (PSA)) and in vitro (measuring peritoneal mast cell (PMC) β-hexosaminidase release and prostaglandin D(2) synthesis). However, under the conditions tested, cromolyn did not inhibit those mast cell-dependent responses in mice. In mice, cromolyn also failed to inhibit the ear swelling or leukocyte infiltration at sites of PCA. Nor did cromolyn inhibit IgE-independent degranulation of mouse PMCs induced by various stimulators in vitro. At 100 mg/kg, a concentration 10 times higher than that which inhibited PSA in rats, cromolyn significantly inhibited the increases in plasma concentrations of mouse mast cell protease-1 (but not of histamine) during PSA, but had no effect on the reduction in body temperature in this setting. Moreover, this concentration of cromolyn (100 mg/kg) also inhibited LPS-induced TNF production in genetically mast cell-deficient C57BL/6-Kit(W-sh/W-sh) mice in vivo. These results question cromolyn's effectiveness and selectivity as an inhibitor of mast cell activation and mediator release in the mouse.
View details for DOI 10.1038/labinvest.2012.116
View details for Web of Science ID 000309324600009
View details for PubMedID 22906983
View details for PubMedCentralID PMC3580174
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The Chymase Mouse Mast Cell Protease 4 Degrades TNF, Limits Inflammation, and Promotes Survival in a Model of Sepsis
AMERICAN JOURNAL OF PATHOLOGY
2012; 181 (3): 875-886
Abstract
Mouse mast cell protease 4 (mMCP-4), the mouse counterpart of human mast cell chymase, is thought to have proinflammatory effects in innate or adaptive immune responses associated with mast cell activation. However, human chymase can degrade the proinflammatory cytokine TNF, a mediator that can be produced by mast cells and many other cell types. We found that mMCP-4 can reduce levels of mouse mast cell-derived TNF in vitro through degradation of transmembrane and soluble TNF. We assessed the effects of interactions between mMCP-4 and TNF in vivo by analyzing the features of a classic model of polymicrobial sepsis, cecal ligation and puncture (CLP), in C57BL/6J-mMCP-4-deficient mice versus C57BL/6J wild-type mice, and in C57BL/6J-Kit(W-sh/W-sh) mice containing adoptively transferred mast cells that were either wild type or lacked mMCP-4, TNF, or both mediators. The mMCP-4-deficient mice exhibited increased levels of intraperitoneal TNF, higher numbers of peritoneal neutrophils, and increased acute kidney injury after CLP, and also had significantly higher mortality after this procedure. Our findings support the conclusion that mMCP-4 can enhance survival after CLP at least in part by limiting detrimental effects of TNF, and suggest that mast cell chymase may represent an important negative regulator of TNF in vivo.
View details for DOI 10.1016/j.ajpath.2012.05.013
View details for Web of Science ID 000309251100016
View details for PubMedID 22901752
View details for PubMedCentralID PMC3432424
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IgE and mast cells in allergic disease
NATURE MEDICINE
2012; 18 (5): 693-704
Abstract
Immunoglobulin E (IgE) antibodies and mast cells have been so convincingly linked to the pathophysiology of anaphylaxis and other acute allergic reactions that it can be difficult to think of them in other contexts. However, a large body of evidence now suggests that both IgE and mast cells are also key drivers of the long-term pathophysiological changes and tissue remodeling associated with chronic allergic inflammation in asthma and other settings. Such potential roles include IgE-dependent regulation of mast-cell functions, actions of IgE that are largely independent of mast cells and roles of mast cells that do not directly involve IgE. In this review, we discuss findings supporting the conclusion that IgE and mast cells can have both interdependent and independent roles in the complex immune responses that manifest clinically as asthma and other allergic disorders.
View details for DOI 10.1038/nm.2755
View details for Web of Science ID 000303763500037
View details for PubMedID 22561833
View details for PubMedCentralID PMC3597223
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Reduced mast cell and basophil numbers and function in Cpa3-Cre; Mcl-1(fl/fl) mice
BLOOD
2011; 118 (26): 6930-6938
Abstract
It has been reported that the intracellular antiapoptotic factor myeloid cell leukemia sequence 1 (Mcl-1) is required for mast cell survival in vitro, and that genetic manipulation of Mcl-1 can be used to delete individual hematopoietic cell populations in vivo. In the present study, we report the generation of C57BL/6 mice in which Cre recombinase is expressed under the control of a segment of the carboxypeptidase A3 (Cpa3) promoter. C57BL/6-Cpa3-Cre; Mcl-1(fl/fl) mice are severely deficient in mast cells (92%-100% reduced in various tissues analyzed) and also have a marked deficiency in basophils (58%-78% reduced in the compartments analyzed), whereas the numbers of other hematopoietic cell populations exhibit little or no changes. Moreover, Cpa3-Cre; Mcl-1(fl/fl) mice exhibited marked reductions in the tissue swelling and leukocyte infiltration that are associated with both mast cell- and IgE-dependent passive cutaneous anaphylaxis (except at sites engrafted with in vitro-derived mast cells) and a basophil- and IgE-dependent model of chronic allergic inflammation, and do not develop IgE-dependent passive systemic anaphylaxis. Our findings support the conclusion that Mcl-1 is required for normal mast cell and basophil development/survival in vivo in mice, and also suggest that Cpa3-Cre; Mcl-1(fl/fl) mice may be useful in analyzing the roles of mast cells and basophils in health and disease.
View details for DOI 10.1182/blood-2011-03-343962
View details for Web of Science ID 000298401000030
View details for PubMedID 22001390
View details for PubMedCentralID PMC3245213
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Mast cell chymase reduces the toxicity of Gila monster venom, scorpion venom, and vasoactive intestinal polypeptide in mice
JOURNAL OF CLINICAL INVESTIGATION
2011; 121 (10): 4180-4191
Abstract
Mast cell degranulation is important in the pathogenesis of anaphylaxis and allergic disorders. Many animal venoms contain components that can induce mast cell degranulation, and this has been thought to contribute to the pathology and mortality caused by envenomation. However, we recently reported evidence that mast cells can enhance the resistance of mice to the venoms of certain snakes and that mouse mast cell-derived carboxypeptidase A3 (CPA3) can contribute to this effect. Here, we investigated whether mast cells can enhance resistance to the venom of the Gila monster, a toxic component of that venom (helodermin), and the structurally similar mammalian peptide, vasoactive intestinal polypeptide (VIP). Using 2 types of mast cell-deficient mice, as well as mice selectively lacking CPA3 activity or the chymase mouse mast cell protease-4 (MCPT4), we found that mast cells and MCPT4, which can degrade helodermin, can enhance host resistance to the toxicity of Gila monster venom. Mast cells and MCPT4 also can limit the toxicity associated with high concentrations of VIP and can reduce the morbidity and mortality induced by venoms from 2 species of scorpions. Our findings support the notion that mast cells can enhance innate defense by degradation of diverse animal toxins and that release of MCPT4, in addition to CPA3, can contribute to this mast cell function.
View details for DOI 10.1172/JCI46139
View details for Web of Science ID 000295601000043
View details for PubMedID 21926462
View details for PubMedCentralID PMC3195461
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Identification of an IFN-gamma/mast cell axis in a mouse model of chronic asthma
JOURNAL OF CLINICAL INVESTIGATION
2011; 121 (8): 3133-3143
Abstract
Asthma is considered a Th2 cell–associated disorder. Despite this, both the Th1 cell–associated cytokine IFN-γ and airway neutrophilia have been implicated in severe asthma. To investigate the relative contributions of different immune system components to the pathogenesis of asthma, we previously developed a model that exhibits several features of severe asthma in humans, including airway neutrophilia and increased lung IFN-γ. In the present studies, we tested the hypothesis that IFN-γ regulates mast cell function in our model of chronic asthma. Engraftment of mast cell–deficient KitW(-sh/W-sh) mice, which develop markedly attenuated features of disease, with wild-type mast cells restored disease pathology in this model of chronic asthma. However, disease pathology was not fully restored by engraftment with either IFN-γ receptor 1–null (Ifngr1–/–) or Fcε receptor 1γ–null (Fcer1g–/–) mast cells. Additional analysis, including gene array studies, showed that mast cell expression of IFN-γR contributed to the development of many FcεRIγ-dependent and some FcεRIγ-independent features of disease in our model, including airway hyperresponsiveness, neutrophilic and eosinophilic inflammation, airway remodeling, and lung expression of several cytokines, chemokines, and markers of an alternatively activated macrophage response. These findings identify a previously unsuspected IFN-γ/mast cell axis in the pathology of chronic allergic inflammation of the airways in mice.
View details for DOI 10.1172/JCI43598
View details for Web of Science ID 000293495500024
View details for PubMedID 21737883
View details for PubMedCentralID PMC3148724
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Evidence that the endothelin A receptor can enhance IgE-dependent anaphylaxis in mice
JOURNAL OF ALLERGY AND CLINICAL IMMUNOLOGY
2011; 128 (2): 424-426
View details for DOI 10.1016/j.jaci.2011.04.012
View details for Web of Science ID 000293280800030
View details for PubMedCentralID PMC3565840
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The chymase, mouse mast cell protease 4, degrades TNF, limits inflammation, and promotes survival in a mouse model of sepsis
AMER ASSOC IMMUNOLOGISTS. 2011
View details for Web of Science ID 000209751706056
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Basophil CD203c Levels Are Increased at Baseline and Can Be Used to Monitor Omalizumab Treatment in Subjects with Nut Allergy
INTERNATIONAL ARCHIVES OF ALLERGY AND IMMUNOLOGY
2011; 154 (4): 318-327
Abstract
Basophils contribute to anaphylaxis and allergies. We examined the utility of assessing basophil-associated surface antigens (CD11b/CD63/CD123/CD203c/CD294) in characterizing and monitoring subjects with nut allergy.We used flow cytometry to analyze basophils at baseline (without any activation) and after ex vivo stimulation of whole blood by addition of nut or other allergens for 2, 10, and 30 min. We also evaluated whether basophil expression of CD11b/CD63/CD123/CD203c/CD294 was altered in subjects treated with anti-IgE monoclonal antibody (omalizumab) to reduce plasma levels of IgE.We demonstrate that basophil CD203c levels are increased at baseline in subjects with nut allergy compared to healthy controls (13 subjects in each group, p < 0.0001). Furthermore, we confirm that significantly increased expression of CD203c occurs on subject basophils when stimulated with the allergen to which the subject is sensitive and can be detected rapidly (10 min of stimulation, n = 11, p < 0.0008). In 5 subjects with severe peanut allergy, basophil CD203c expression following stimulation with peanut allergen was significantly decreased (p < 0.05) after 4 and 8 weeks of omalizumab treatment but returned toward pretreatment levels after treatment cessation.Subjects with nut allergy show an increase of basophil CD203c levels at baseline and following rapid ex vivo stimulation with nut allergen. Both can be reduced by omalizumab therapy. These results highlight the potential of using basophil CD203c levels for baseline diagnosis and therapeutic monitoring in subjects with nut allergy.
View details for DOI 10.1159/000321824
View details for Web of Science ID 000288529200007
View details for PubMedID 20975283
View details for PubMedCentralID PMC3214954
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Mast Cells: Effector Cells of Anaphylaxis
ANAPHYLAXIS AND HYPERSENSITIVITY REACTIONS
2011: 47–68
View details for DOI 10.1007/978-1-60327-951-2_4
View details for Web of Science ID 000286149900004
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Mast cells
INFLAMMATION AND ALLERGY DRUG DESIGN
2011: 79–105
View details for Web of Science ID 000337021900008
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MAST CELLS AND IMMUNOREGULATION/IMMUNOMODULATION
MAST CELL BIOLOGY: CONTEMPORARY AND EMERGING TOPICS
2011; 716: 186-211
Abstract
Mast cells often represent one of the first cells of the immune system to interact with environmental antigens, invading pathogens or environmentally-derived toxins. Mast cells also can undergo alterations in phenotype, anatomic distribution and numbers during innate or adaptive immune responses. In addition to their well-known roles as effector cells during IgE- and antigen-induced allergic reactions, mast cells can be activated by many other signals, including some that are derived directly from pathogens or which are generated during innate or adaptive immune responses. Mast cells also express many costimulatory molecules with immunoregulatory activities and can secrete many products that can positively or negatively regulate immune responses. In this chapter, we describe mouse models used for analyzing mast-cell function in vivo and illustrate how such models have been used to identify positive or negative immunomodulatory roles for mast cells during specific innate or adaptive immune responses. We also briefly describe some of the mast-cell functions, products and surface receptors that have the potential to permit mast cells to promote or suppress immune responses that can either enhance host defense or contribute to disease.
View details for Web of Science ID 000290066600011
View details for PubMedID 21713658
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Thymic Stromal Lymphopoietin Contributes to Myeloid Hyperplasia and Increased Immunoglobulins, But Not Epidermal Hyperplasia, in RabGEF1-Deficient Mice
AMERICAN JOURNAL OF PATHOLOGY
2010; 177 (5): 2411-2420
Abstract
Mice overexpressing the proallergic cytokine thymic stromal lymphopoietin (TSLP) in the skin develop a pathology resembling atopic dermatitis. RabGEF1, a guanine nucleotide exchange factor for Rab5 GTPase, is a negative regulator of IgE-dependent mast cell activation, and Rabgef1-/- and TSLP transgenic mice share many similar phenotypic characteristics, including elevated serum IgE levels and severe skin inflammation, with infiltrates of both lymphocytes and eosinophils. We report here that Rabgef1-/- mice also develop splenomegaly, lymphadenopathy, myeloid hyperplasia, and high levels of TSLP. Rabgef1-/-TSLPR-/- mice, which lack TSLP/TSLP receptor (TSLPR) signaling, had levels of blood neutrophils, spleen myeloid cells, and serum IL-4, IgG1, and IgE levels that were significantly reduced compared with those in Rabgef1-/-TSLPR+/+ mice. However, Rabgef1-/-TSLPR-/- mice, like Rag1- or eosinophil-deficient Rabgef1-/- mice, developed cutaneous inflammation and epidermal hyperplasia. Therefore, in Rabgef1-/- mice, TSLP/TSLPR interactions are not required for the development of epidermal hyperplasia but contribute to the striking myeloid hyperplasia and overproduction of immunoglobulins observed in these animals. Our study shows that RabGEF1 can negatively regulate TSLP production in vivo and that excessive production of TSLP contributes to many of the phenotypic abnormalities in Rabgef1-/- mice. However, the marked epidermal hyperplasia, cutaneous inflammation, and increased numbers of dermal mast cells associated with RabGEF1 deficiency can develop via a TSLPR-independent pathway, as well as in the absence of Rag1 or eosinophils.
View details for DOI 10.2353/ajpath.2010.100181
View details for Web of Science ID 000284182900028
View details for PubMedID 20829437
View details for PubMedCentralID PMC2966799
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Mast cells in allergy and infection: Versatile effector and regulatory cells in innate and adaptive immunity
EUROPEAN JOURNAL OF IMMUNOLOGY
2010; 40 (7): 1843-1851
Abstract
Mast cells are widely distributed in tissues, particularly near surfaces exposed to the environment. Mast cells can be activated to secrete diverse mediators and cytokines by IgE and specific Ag and many other stimuli, including products derived from either pathogens or the host during innate immune responses. Although mast cells are best known for their role in IgE-associated allergic disorders, mast cells can also exacerbate models of autoimmunity, enhance the sensitization and/or effector phases of certain cutaneous contact hypersensitivity responses, and increase inflammation and mortality during some severe bacterial infections. In other settings, however, mast cells can limit inflammation and tissue injury: mast cells promote host resistance in certain models of bacterial or parasite infection, limit pathology during some acquired immune responses to environmental Ag, including examples of severe contact hypersensitivity, and have adjuvant-like properties that can enhance the development of protective immunity against pathogens. These and other findings suggest that mast cells occupy a critical niche at the interface of innate and acquired immunity, where, depending on circumstances that remain to be fully understood, mast cells may function to perturb or help to restore homeostasis (or both), with consequences that can either promote health or contribute to disease.
View details for DOI 10.1002/eji.201040559
View details for Web of Science ID 000280220600012
View details for PubMedID 20583030
View details for PubMedCentralID PMC3581154
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The role of recipient mast cells in acute and chronic cardiac allograft rejection in C57BL/6-KitW-sh/W-sh mice
JOURNAL OF HEART AND LUNG TRANSPLANTATION
2010; 29 (4): 401-409
Abstract
Mast cells are hypothesized to promote rejection and adverse remodeling in cardiac allografts. In contrast, it has been reported that mast cells may enhance cardiac allograft survival in rats. We used C57BL/6-Kit(W-sh/W-sh) mast cell-deficient and corresponding wild-type mice to investigate possible contributions of recipient mast cells to acute or chronic cardiac allograft rejection.FVB (H-2(q); acute rejection), or C-H-2(bm12)KhEg (H-2(bm12); chronic rejection) donor hearts were heterotopically transplanted into C57BL/6-Kit(W-sh/W-sh) (H-2(b)) or C57BL/6-Kit(+/+) (H-2(b)) mice. The degree of acute rejection was assessed at 5 days and chronic rejection, at 52 days.In the acute rejection model, donor heart vascular cell adhesion molecule-1 (VCAM-1) expression was significantly lower in C57BL/6-Kit(W-sh/W-sh) than in wild-type recipients; however, acute rejection scores, graft survival, inflammatory cells, or cytokine expression did not differ significantly. In the chronic rejection model, the number of mast cells/mm(2) of allograft tissue was significantly increased 52 days after transplantation in allografts transplanted into C57BL/6-Kit(+/+) but not C57BL/6-Kit(W-sh/W-sh) mice; however, no substantial differences were noted in graft coronary artery disease, graft inflammatory cells, or levels of graft tissue expression of cytokines or adhesion molecules.Cardiac allografts undergoing chronic rejection in wild-type C57BL/6-Kit(+/+) mice exhibit increased numbers of mast cells, but acute or chronic cardiac allograft rejection can develop in C57BL/6-Kit(W-sh/W-sh) mice even though these recipients virtually lack mast cells. These findings indicate that recipient mast cells are not required for acute or chronic cardiac allograft rejection in the models examined.
View details for DOI 10.1016/j.healun.2009.08.019
View details for Web of Science ID 000276915100003
View details for PubMedID 19818646
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Mast Cell-Derived TNF Can Exacerbate Mortality during Severe Bacterial Infections in C57BL/6-KitW-sh/W-sh Mice
AMERICAN JOURNAL OF PATHOLOGY
2010; 176 (2): 926-938
Abstract
We used mast cell-engrafted genetically mast cell-deficient C57BL/6-Kit(W-sh/W-sh) mice to investigate the roles of mast cells and mast cell-derived tumor necrosis factor in two models of severe bacterial infection. In these mice, we confirmed findings derived from studies of mast cell-deficient WBB6F(1)-Kit(W/W-v) mice indicating that mast cells can promote survival in cecal ligation and puncture (CLP) of moderate severity. However, we found that the beneficial role of mast cells in this setting can occur independently of mast cell-derived tumor necrosis factor. By contrast, using mast cell-engrafted C57BL/6-Kit(W-sh/W-sh) mice, we found that mast cell-derived tumor necrosis factor can increase mortality during severe CLP and can also enhance bacterial growth and hasten death after intraperitoneal inoculation of Salmonella typhimurium. In WBB6F(1)-Kit(W-sh/W-sh) mice, mast cells enhanced survival during moderately severe CLP but did not significantly change the survival observed in severe CLP. Our findings in three types of genetically mast cell-deficient mice thus support the hypothesis that, depending on the circumstances (including mouse strain background, the nature of the mutation resulting in a mast cell deficiency, and type and severity of infection), mast cells can have either no detectable effect or opposite effects on survival during bacterial infections, eg, promoting survival during moderately severe CLP associated with low mortality but, in C57BL/6-Kit(W-sh/W-sh) mice, increasing mortality during severe CLP or infection with S. typhimurium.
View details for DOI 10.2353/ajpath.2010.090342
View details for Web of Science ID 000274111400040
View details for PubMedID 20035049
View details for PubMedCentralID PMC2808097
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IL-3 is required for increases in blood basophils in nematode infection in mice and can enhance IgE-dependent IL-4 production by basophils in vitro
LABORATORY INVESTIGATION
2008; 88 (11): 1134-1142
Abstract
Basophils represent potential effector and immunoregulatory cells, as well as a potential source of IL-4, during the immune response elicited by infection with the nematode Nippostrongylus brasiliensis (N.b.), and in other settings. However, the factors which regulate the numbers of blood basophils in mice, or the ability of these cells to produce IL-4, are not fully understood. We found that infection of mice with the nematodes N.b. or Strongyloides venezuelensis (S.v.) induced substantial increases in the numbers of blood basophils (to as high as 18% of circulating blood leukocytes). Experiments in IL-3-/- vs IL-3+/+ mice, and in IL-3-treated IL-3-/- mice, showed that essentially all of the increases in blood or bone marrow basophils during N.b. or S.v. infection were IL-3 dependent. Many of the blood, bone marrow or liver-derived basophils from IL-3-/- or IL-3+/+ mice expressed intracellular IL-4 upon stimulation with anti-IgE in vitro. However, after incubation of the cells with exogenous IgE in vitro, blood- or liver-derived basophils from IL-3+/+ mice exhibited higher levels of intracellular IL-4 after stimulation with anti-IgE than did basophils derived from IL-3-/- mice. Thus, IL-3 is a major regulator of the marked increases in blood basophil levels observed during infection of mice with N.b. or S.v. and also can enhance levels of intracellular IL-4 upon activation of basophils with anti-IgE in vitro.
View details for DOI 10.1038/labinvest.2008.88
View details for Web of Science ID 000260427600001
View details for PubMedID 18975389
View details for PubMedCentralID PMC2788437
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The development of allergic inflammation
NATURE
2008; 454 (7203): 445-454
Abstract
Allergic disorders, such as anaphylaxis, hay fever, eczema and asthma, now afflict roughly 25% of people in the developed world. In allergic subjects, persistent or repetitive exposure to allergens, which typically are intrinsically innocuous substances common in the environment, results in chronic allergic inflammation. This in turn produces long-term changes in the structure of the affected organs and substantial abnormalities in their function. It is therefore important to understand the characteristics and consequences of acute and chronic allergic inflammation, and in particular to explore how mast cells can contribute to several features of this maladaptive pattern of immunological reactivity.
View details for DOI 10.1038/nature07204
View details for Web of Science ID 000257860300039
View details for PubMedID 18650915
View details for PubMedCentralID PMC3573758
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Immunomodulatory mast cells: negative, as well as positive, regulators of immunity
NATURE REVIEWS IMMUNOLOGY
2008; 8 (6): 478-U14
Abstract
Mast cells can promote inflammation and other tissue changes in IgE-associated allergic disorders, as well as in certain innate and adaptive immune responses that are thought to be independent of IgE. However, mast cells can also have anti-inflammatory and immunosuppressive functions. Here, we review the evidence that mast cells can have negative, as well as positive, immunomodulatory roles in vivo, and we propose that mast cells can both enhance and later suppress certain features of an immune response.
View details for DOI 10.1038/nri2327
View details for Web of Science ID 000256105700018
View details for PubMedID 18483499
View details for PubMedCentralID PMC2855166
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Neurotensin increases mortality and mast cells reduce neurotensin levels in a mouse model of sepsis
NATURE MEDICINE
2008; 14 (4): 392-398
Abstract
Sepsis is a complex, incompletely understood and often fatal disorder, typically accompanied by hypotension, that is considered to represent a dysregulated host response to infection. Neurotensin (NT) is a 13-amino-acid peptide that, among its multiple effects, induces hypotension. We find that intraperitoneal and plasma concentrations of NT are increased in mice after severe cecal ligation and puncture (CLP), a model of sepsis, and that mice treated with a pharmacological antagonist of NT, or NT-deficient mice, show reduced mortality during severe CLP. In mice, mast cells can degrade NT and reduce NT-induced hypotension and CLP-associated mortality, and optimal expression of these effects requires mast cell expression of neurotensin receptor 1 and neurolysin. These findings show that NT contributes to sepsis-related mortality in mice during severe CLP and that mast cells can lower NT concentrations, and suggest that mast cell-dependent reduction in NT levels contributes to the ability of mast cells to enhance survival after CLP.
View details for DOI 10.1038/nm1738
View details for Web of Science ID 000254674100025
View details for PubMedID 18376408
View details for PubMedCentralID PMC2873870
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Mast cells: Versatile regulators of inflammation, tissue remodeling, host defense and homeostasis
JOURNAL OF DERMATOLOGICAL SCIENCE
2008; 49 (1): 7-19
Abstract
The possible roles of mast cells in heath and disease have been a topic of interest for over 125 years. Many adaptive or pathological processes affecting the skin or other anatomical sites have been associated with morphological evidence of mast cell activation, and/or with changes in mast cell numbers or phenotype. Such observations, taken together with the known functions of the diverse mediators, cytokines and growth factors which can be secreted by mast cells, have suggested many potential functions for mast cells in health and disease. Definitively identifying the importance of mast cells in biological responses in humans is difficult. However, mutant mice which are profoundly mast cell-deficient, especially those which can undergo engraftment with wild-type or genetically altered mast cells, provide an opportunity to investigate the importance of mast cells, and specific mast cell functions or products, in various adaptive or pathological responses in mice. Such work has shown that mast cells can significantly influence multiple features of inflammatory or immune responses, through diverse effects that can either promote or, surprisingly, suppress, aspects of these responses. Through such functions, mast cells can significantly influence inflammation, tissue remodeling, host defense and homeostasis.
View details for DOI 10.1016/j.jdermsci.2007.09.009
View details for Web of Science ID 000252523500003
View details for PubMedID 18024086
View details for PubMedCentralID PMC2788430
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Mast cell-derived interleukin 10 limits skin pathology in contact dermatitis and chronic irradiation with ultraviolet B
NATURE IMMUNOLOGY
2007; 8 (10): 1095-1104
Abstract
Allergic contact dermatitis, such as in response to poison ivy or poison oak, and chronic low-dose ultraviolet B irradiation can damage the skin. Mast cells produce proinflammatory mediators that are thought to exacerbate these prevalent acquired immune or innate responses. Here we found that, unexpectedly, mast cells substantially limited the pathology associated with these responses, including infiltrates of leukocytes, epidermal hyperplasia and epidermal necrosis. Production of interleukin 10 by mast cells contributed to the anti-inflammatory or immunosuppressive effects of mast cells in these conditions. Our findings identify a previously unrecognized function for mast cells and mast cell-derived interleukin 10 in limiting leukocyte infiltration, inflammation and tissue damage associated with immunological or innate responses that can injure the skin.
View details for DOI 10.1038/ni1503
View details for Web of Science ID 000249691400024
View details for PubMedID 17767162
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Roles of RabGEF1/Rabex-5 domains in regulating Fc epsilon RI surface expression and Fc epsilon RI-dependent responses in mast cells
BLOOD
2007; 109 (12): 5308-5317
Abstract
RabGEF1/Rabex-5, a guanine nucleotide exchange factor (GEF) for the endocytic pathway regulator, Rab5, contains a Vps9 domain, an A20-like zinc finger (ZnF) domain, and a coiled coil domain. To investigate the importance of these domains in regulating receptor internalization and cell activation, we lentivirally delivered RabGEF1 mutants into RabGEF1-deficient (-/-) mast cells and examined Fc epsilon RI-dependent responses. Wild-type RabGEF1 expression corrected phenotypic abnormalities in -/- mast cells, including decreased basal Fc epsilon RI expression, slowed Fc epsilon RI internalization, elevated IgE + Ag-induced degranulation and IL-6 production, and the decreased ability of -/- cytosol to support endosome fusion. We showed that RabGEF1's ZnF domain has ubiquitin ligase activity. Moreover, the coiled coil domain of RabGEF1 is required for Rabaptin-5 binding and for maintaining basal levels of Rabaptin-5 and surface Fc epsilon RI. However, mutants lacking either of these domains normalized phenotypic abnormalities in IgE + antigen-activated -/- mast cells. By contrast, correction of these -/- phenotypes required a functional Vps9 domain. Thus, Fc epsilon RI-mediated mast cell functional activation is dependent on RabGEF1's GEF activity.
View details for DOI 10.1182/blood-2007-01-067363
View details for Web of Science ID 000247360200045
View details for PubMedID 17341663
View details for PubMedCentralID PMC1890836
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Mast cells in the promotion and limitation of chronic inflammation
IMMUNOLOGICAL REVIEWS
2007; 217: 304-328
Abstract
Observations of increased numbers of mast cells at sites of chronic inflammation have been reported for over a hundred years. Light and electron microscopic evidence of mast cell activation at such sites, taken together with the known functions of the diverse mediators, cytokines, and growth factors that can be secreted by appropriately activated mast cells, have suggested a wide range of possible functions for mast cells in promoting (or suppressing) many features of chronic inflammation. Similarly, these and other lines of evidence have implicated mast cells in a variety of adaptive or pathological responses that are associated with persistent inflammation at the affected sites. Definitively characterizing the importance of mast cells in chronic inflammation in humans is difficult. However, mice that genetically lack mast cells, especially those which can undergo engraftment with wildtype or genetically altered mast cells, provide a means to investigate the importance of mast cells and specific mast cell functions or products in diverse models of chronic inflammation. Such work has confirmed that mast cells can significantly influence multiple features of chronic inflammatory responses, through diverse effects that can either promote or, perhaps more surprisingly, suppress aspects of these responses.
View details for Web of Science ID 000246317100022
View details for PubMedID 17498068
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TNF can contribute to multiple features of ovalbumin-induced allergic inflammation of the airways in mice
JOURNAL OF ALLERGY AND CLINICAL IMMUNOLOGY
2007; 119 (3): 680-686
Abstract
TNF is thought to contribute to airway hyperreactivity (AHR) and airway inflammation in asthma. However, studies with TNF-deficient or TNF receptor-deficient mice have not produced a clear picture of the role of TNF in the AHR associated with allergic inflammation in the mouse.We used a genetic approach to investigate the contributions of TNF to antigen-induced AHR and airway inflammation in mice on the C57BL/6 background.We analyzed features of airway allergic inflammation, including antigen-induced AHR, in C57BL/6 wild-type and TNF(-/-) mice, using 2 different methods for sensitizing the mice to ovalbumin (OVA).In mice sensitized to OVA administered with the adjuvant aluminum hydroxide (alum), which develop IgE-independent and mast cell-independent allergic inflammation and AHR, we found no significant differences in OVA-induced AHR in C57BL/6-TNF(-/-) versus wild-type mice. By contrast, in mice sensitized to OVA without alum, which develop allergic inflammation that is significantly mast cell-dependent, C57BL/6-TNF(-/-) mice exhibited significant reductions versus wild-type mice in OVA-induced AHR to methacholine; numbers of lymphocytes, neutrophils, and eosinophils in bronchoalveolar lavage fluid; levels of myeloperoxidase, eosinophil peroxidase, and the cytokines IL-4, IL-5, and IL-17 in lung tissue; and histologic evidence of pulmonary inflammation.In pulmonary allergic inflammation induced in mice immunized with OVA without alum, TNF significantly contributes to several features of the response, including antigen-induced inflammation and AHR.Our findings in mice support the hypothesis that TNF can promote the allergic inflammation and AHR associated with asthma.
View details for DOI 10.1016/j.jaci.2006.11.701
View details for Web of Science ID 000244925000022
View details for PubMedID 17336618
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Effector and potential immunoregulatory roles of mast cells in IgE-associated acquired immune responses
CURRENT OPINION IN IMMUNOLOGY
2006; 18 (6): 751-760
Abstract
Mast cells are best known as critical effector cells in anaphylaxis and other examples of IgE-associated immediate hypersensitivity reactions. However, mast cells also can contribute to the development of the late-phase responses that occur in some sensitized subjects hours after initial exposure to specific antigen, and can promote many of the features of chronic allergic inflammation, including tissue remodeling and functional changes in the affected organs. In addition to such effector cell functions in IgE-associated immune responses, recent evidence indicates that mast cells can importantly influence the sensitization phase of at least some acquired immune responses, and can contribute to the pathology of autoimmune disorders and to the expression of peripheral tolerance.
View details for DOI 10.1016/j.coi.2006.09.011
View details for Web of Science ID 000242036900018
View details for PubMedID 17011762
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Mast cell-derived tumor necrosis factor can promote nerve fiber elongation in the skin during contact hypersensitivity in mice
AMERICAN JOURNAL OF PATHOLOGY
2006; 169 (5): 1713-1721
Abstract
In humans, lesions of contact eczema or atopic dermatitis can exhibit increases in epidermal nerves, but the mechanism resulting in such nerve elongation are not fully understood. We found that contact hypersensitivity reactions to oxazolone in mice were associated with significant increases in the length of nerves in the epidermis and dermis. Using genetically mast cell-deficient c-kit mutant mice selectively repaired of their dermal mast cell deficiency with either wild-type or tumor necrosis factor (TNF)-deficient mast cells, we found that mast cells, and mast cell-derived TNF, significantly contributed to the elongation of epidermal and dermal PGP 9.5+ nerves and dermal CGRP+ nerves, as well as to the inflammation observed at sites of contact hypersensitivity in response to oxazolone. Moreover, the percentage of mast cells in close proximity to dermal PGP 9.5+ nerve fibers was significantly higher in wild-type mice and in c-kit mutant mice repaired of their dermal mast cell deficiency by the adoptive transfer of wild-type mast cells than in TNF-deficient mice or in TNF-/- mast cell-engrafted c-kit mutant mice. These observations show that mast cells, and mast cell-derived TNF, can promote the elongation of cutaneous nerve fibers during contact hypersensitivity in the mouse.
View details for DOI 10.2353/ajpath.2006.060602
View details for Web of Science ID 000241603700019
View details for PubMedID 17071594
View details for PubMedCentralID PMC1780201
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Mast cells can enhance resistance to snake and honeybee venoms
SCIENCE
2006; 313 (5786): 526-530
Abstract
Snake or honeybee envenomation can cause substantial morbidity and mortality, and it has been proposed that the activation of mast cells by snake or insect venoms can contribute to these effects. We show, in contrast, that mast cells can significantly reduce snake-venom-induced pathology in mice, at least in part by releasing carboxypeptidase A and possibly other proteases, which can degrade venom components. Mast cells also significantly reduced the morbidity and mortality induced by honeybee venom. These findings identify a new biological function for mast cells in enhancing resistance to the morbidity and mortality induced by animal venoms.
View details for DOI 10.1126/science.1128877
View details for Web of Science ID 000239308600064
View details for PubMedID 16873664
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Mast cells can promote the development of multiple features of chronic asthma in mice
JOURNAL OF CLINICAL INVESTIGATION
2006; 116 (6): 1633-1641
Abstract
Bronchial asthma, the most prevalent cause of significant respiratory morbidity in the developed world, typically is a chronic disorder associated with long-term changes in the airways. We developed a mouse model of chronic asthma that results in markedly increased numbers of airway mast cells, enhanced airway responses to methacholine or antigen, chronic inflammation including infiltration with eosinophils and lymphocytes, airway epithelial goblet cell hyperplasia, enhanced expression of the mucin genes Muc5ac and Muc5b, and increased levels of lung collagen. Using mast cell-deficient (Kit(W-sh/W-sh) and/or Kit(W/W-v)) mice engrafted with FcRgamma+/+ or FcRgamma-/- mast cells, we found that mast cells were required for the full development of each of these features of the model. However, some features also were expressed, although usually at less than wild-type levels, in mice whose mast cells lacked FcRgamma and therefore could not be activated by either antigen- and IgE-dependent aggregation of Fc epsilonRI or the binding of antigen-IgG1 immune complexes to Fc gammaRIII. These findings demonstrate that mast cells can contribute to the development of multiple features of chronic asthma in mice and identify both Fc Rgamma-dependent and Fc Rgamma-independent pathways of mast cell activation as important for the expression of key features of this asthma model.
View details for DOI 10.1172/JCI25702
View details for Web of Science ID 000237979700025
View details for PubMedID 16710480
View details for PubMedCentralID PMC1462940
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Mast cell-associated TNF promotes dendritic cell migration
JOURNAL OF IMMUNOLOGY
2006; 176 (7): 4102-4112
Abstract
Mast cells represent a potential source of TNF, a mediator which can enhance dendritic cell (DC) migration. Although the importance of mast cell-associated TNF in regulating DC migration in vivo is not clear, mast cells and mast cell-derived TNF can contribute to the expression of certain models of contact hypersensitivity (CHS). We found that CHS to FITC was significantly impaired in mast cell-deficient Kit(W-sh/W-sh) or TNF(-/)(-) mice. The reduced expression of CHS in Kit(W-sh/W-sh) mice was fully repaired by local transfer of wild-type bone marrow-derived cultured mast cells (BMCMCs), but was only partially repaired by transfer of TNF(-/)(-) BMCMCs. Thus, mast cells, and mast cell-derived TNF, were required for optimal expression of CHS to FITC. We found that the migration of FITC-bearing skin DCs into draining lymph nodes (LNs) 24 h after epicutaneous administration of FITC in naive mice was significantly reduced in mast cell-deficient or TNF(-/)(-) mice, but levels of DC migration in these mutant mice increased to greater than wild-type levels by 48 h after FITC sensitization. Mast cell-deficient or TNF(-/)(-) mice also exhibited significantly reduced migration of airway DCs to local LNs at 24 h after intranasal challenge with FITC-OVA. Migration of FITC-bearing DCs to LNs draining the skin or airways 24 h after sensitization was repaired in Kit(W-sh/W-sh) mice which had been engrafted with wild-type but not TNF(-/)(-) BMCMCs. Our findings indicate that mast cell-associated TNF can contribute significantly to the initial stages of FITC-induced migration of cutaneous or airway DCs.
View details for Web of Science ID 000238769300035
View details for PubMedID 16547246
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RabGEF1 regulates stem cell factor/c-Kit-mediated signaling events and biological responses in mast cells
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
2006; 103 (8): 2659-2664
Abstract
We recently reported that RabGEF1 is a negative regulator of high-affinity Fc receptor for IgE (Fc epsilonRI)-dependent mast cell activation and that mice lacking RabGEF1 develop severe skin inflammation and increased numbers of dermal mast cells. To better understand how RabGEF1 can regulate signaling events and biological responses in mast cells, we examined the responses of bone marrow-derived cultured mast cells (BMCMCs) from wild-type (+/+) and Rabgef1 knockout (-/-) mice after stimulation with the c-Kit ligand, stem cell factor (SCF), an important regulator of mast cell development, survival, proliferation, and activation. We found that RabGEF1-deficient mast cells exhibited enhanced and prolonged activation of Ras and extracellular regulated kinase, and significantly elevated IL-6 secretion, after stimulation with SCF. SCF-induced activation of c-Jun N-terminal kinase was increased in Rabgef1-/- BMCMCs, but without corresponding significant increases in SCF-induced migration or adhesion. SCF-mediated activation of the survival-enhancing kinase, Akt, also was increased in Rabgef1-/- BMCMCs, and these cells had a survival advantage over their +/+ counterparts in vitro. Despite enhanced Ras activation in the absence of RabGEF1, SCF-induced proliferation was lower in Rabgef1-/- BMCMCs compared with their +/+ counterparts. Finally, we found that c-Kit internalization was delayed in the absence of RabGEF1, probably reflecting a positive role for RabGEF1 in the regulation of endocytic events, and that infection of Rabgef1-/- BMCMCs with a wild-type RabGEF1 lentiviral construct normalized c-Kit internalization to the levels seen in +/+ BMCMCs. Thus, RabGEF1 plays a critical role in the regulation of SCF/c-Kit-mediated signaling events and biological responses in mast cells.
View details for Web of Science ID 000235554900034
View details for PubMedID 16533754
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Mast cells enhance T cell activation: Importance of mast cell costimulatory molecules and secreted TNF
JOURNAL OF IMMUNOLOGY
2006; 176 (4): 2238-2248
Abstract
We recently reported that mast cells stimulated via FcepsilonRI aggregation can enhance T cell activation by a TNF-dependent mechanism. However, the molecular mechanisms responsible for such IgE-, Ag- (Ag-), and mast cell-dependent enhancement of T cell activation remain unknown. In this study we showed that mouse bone marrow-derived cultured mast cells express various costimulatory molecules, including members of the B7 family (ICOS ligand (ICOSL), PD-L1, and PD-L2) and the TNF/TNFR families (OX40 ligand (OX40L), CD153, Fas, 4-1BB, and glucocorticoid-induced TNFR). ICOSL, PD-L1, PD-L2, and OX40L also are expressed on APCs such as dendritic cells and can modulate T cell function. We found that IgE- and Ag-dependent mast cell enhancement of T cell activation required secreted TNF; that TNF can increase the surface expression of OX40, ICOS, PD-1, and other costimulatory molecules on CD3(+) T cells; and that a neutralizing Ab to OX40L, but not neutralizing Abs to ICOSL or PD-L1, significantly reduced IgE/Ag-dependent mast cell-mediated enhancement of T cell activation. These results indicate that the secretion of soluble TNF and direct cell-cell interactions between mast cell OX40L and T cell OX40 contribute to the ability of IgE- and Ag-stimulated mouse mast cells to enhance T cell activation.
View details for Web of Science ID 000235180900025
View details for PubMedID 16455980
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Monomeric IgE enhances human mast cell chemokine production: ILA-4 augments and dexamethasone suppresses the response
JOURNAL OF ALLERGY AND CLINICAL IMMUNOLOGY
2005; 116 (6): 1357-1363
Abstract
Mouse monoclonal IgE antibodies can promote the survival of mouse bone marrow-derived cultured mast cells and induce the cells to secrete mediators in the absence of known specific antigen.To determine whether human IgE, in the absence of known specific antigen, had effects on the mediator secretion or survival of human mast cells.We tested whether human IgE induced human cord blood-derived mast cells to secrete mediators or enhanced their survival on withdrawal of stem cell factor.Exposure to IgE, but not IgG, at concentrations as low as 2.5 microg/mL significantly enhanced the release of IL-8 and monocyte chemoattractant protein 1, but not histamine or cysteinyl leukotrienes. However, under the conditions tested, chemokine production in response to IgE alone was significantly less than that induced when aliquots of the same IgE-sensitized populations of human mast cells were stimulated with anti-IgE. The production of IL-8 and monocyte chemoattractant protein 1 in response to either IgE alone or IgE and anti-IgE was enhanced by preincubation of the cells in IL-4 and was inhibited by preincubation of the cells with dexamethasone. By contrast, we did not detect any ability of IgE to enhance mast cell survival on withdrawal of stem cell factor.Exposure to human IgE in vitro in the absence of known specific antigen can enhance chemokine production by human mast cells, and this secretory response can be enhanced by preincubation of the mast cells with IL-4 and can be suppressed by dexamethasone.
View details for DOI 10.1016/j.jaci.2005.08.042
View details for Web of Science ID 000235687000030
View details for PubMedID 16337471
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Mast cell-deficient W-sash c-kit mutant Kit(W-sh/W-sh) mice as a model for investigating mast cell biology in vivo
AMERICAN JOURNAL OF PATHOLOGY
2005; 167 (3): 835-848
Abstract
Mice carrying certain mutations in the white spotting (W) locus (ie, c-kit) exhibit reduced c-kit tyrosine kinase-dependent signaling that results in mast cell deficiency and other phenotypic abnormalities. The c-kit mutations in Kit(W/W-v) mice impair melanogenesis and result in anemia, sterility, and markedly reduced levels of tissue mast cells. In contrast, Kit(W-sh/W-sh) mice, bearing the W-sash (W(sh)) inversion mutation, have mast cell deficiency but lack anemia and sterility. We report that adult Kit(W-sh/W-sh) mice had a profound deficiency in mast cells in all tissues examined but normal levels of major classes of other differentiated hematopoietic and lymphoid cells. Unlike Kit(W/W-v) mice, Kit(W-sh/W-sh) mice had normal numbers of TCR gammadelta intraepithelial lymphocytes in the intestines and did not exhibit a high incidence of idiopathic dermatitis, ulcers, or squamous papillomas of the stomach, but like Kit(W/W-v) mice, they lacked interstitial cells of Cajal in the gut and exhibited bile reflux into the stomach. Systemic or local reconstitution of mast cell populations was achieved in nonirradiated adult Kit(W-sh/W-sh) mice by intravenous, intraperitoneal, or intradermal injection of wild-type bone marrow-derived cultured mast cells but not by transplantation of wild-type bone marrow cells. Thus, Kit(W-sh/W-sh) mice represent a useful model for mast cell research, especially for analyzing mast cell function in vivo.
View details for Web of Science ID 000231514500018
View details for PubMedID 16127161
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Identification of mast cell progenitors in adult mice
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
2005; 102 (32): 11408-11413
Abstract
It is well known that mast cells are derived from hematopoietic stem cells. However, in adult hematopoiesis, a committed mast cell progenitor has not yet been identified in any species, nor is it clear at what point during adult hematopoiesis commitment to the mast cell lineage occurs. We identified a cell population in adult mouse bone marrow, characterized as Lin(-)c-Kit(+)Sca-1(-)-Ly6c(-)FcepsilonRIalpha(-)CD27(-)beta7(+)T1/ST2+, that gives rise only to mast cells in culture and that can reconstitute the mast cell compartment when transferred into c-kit mutant mast cell-deficient mice. In addition, our experiments strongly suggest that these adult mast cell progenitors are derived directly from multipotential progenitors instead of, as previously proposed, common myeloid progenitors or granulocyte/macrophage progenitors.
View details for DOI 10.1073/pnas.0504197102
View details for Web of Science ID 000231253400051
View details for PubMedID 16006518
View details for PubMedCentralID PMC1183570
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Mast cells enhance T cell activation: Importance of mast cell-derived TNF
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
2005; 102 (18): 6467-6472
Abstract
Mast cells are not only important effector cells in immediate hypersensitivity reactions and immune responses to pathogens but also can contribute to T cell-mediated disorders. However, the mechanisms by which mast cells might influence T cells in such settings are not fully understood. We find that mast cells can enhance proliferation and cytokine production in multiple T cell subsets. Mast cell-dependent enhancement of T cell activation can be promoted by FcepsilonRI-dependent mast cell activation, TNF production by both mast cells and T cells, and mast cell-T cell contact. However, at high concentrations of cells, mast cells can promote T cell activation independent of IgE or TNF. Finally, mast cells also can promote T cell activation by means of soluble factors. These findings identify multiple mechanisms by which mast cells can influence T cell proliferation and cytokine production.
View details for DOI 10.1073/pnas.0501912102
View details for Web of Science ID 000228918400041
View details for PubMedID 15840716
View details for PubMedCentralID PMC1088381
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Mast cells in the development of adaptive immune responses
NATURE IMMUNOLOGY
2005; 6 (2): 135-142
Abstract
Mast cells are so widely recognized as critical effector cells in allergic disorders and other immunoglobulin E-associated acquired immune responses that it can be difficult to think of them in any other context. However, mast cells also can be important as initiators and effectors of innate immunity. In addition, mast cells that are activated during innate immune responses to pathogens, or in other contexts, can secrete products and have cellular functions with the potential to facilitate the development, amplify the magnitude or regulate the kinetics of adaptive immune responses. Thus, mast cells may influence the development, intensity and duration of adaptive immune responses that contribute to host defense, allergy and autoimmunity, rather than simply functioning as effector cells in these settings.
View details for DOI 10.1038/ni1158
View details for Web of Science ID 000226468100016
View details for PubMedID 15662442
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Mast cells as "tunable" effector and immunoregulatory cells: Recent advances
ANNUAL REVIEW OF IMMUNOLOGY
2005; 23: 749-786
Abstract
This review focuses on recent progress in our understanding of how mast cells can contribute to the initiation, development, expression, and regulation of acquired immune responses, both those associated with IgE and those that are apparently expressed independently of this class of Ig. We emphasize findings derived from in vivo studies in mice, particularly those employing genetic approaches to influence mast cell numbers and/or to alter or delete components of pathways that can regulate mast cell development, signaling, or function. We advance the hypothesis that mast cells not only can function as proinflammatory effector cells and drivers of tissue remodeling in established acquired immune responses, but also may contribute to the initiation and regulation of such responses. That is, we propose that mast cells can also function as immunoregulatory cells. Finally, we show that the notion that mast cells have primarily two functional configurations, off (or resting) or on (or activated for extensive mediator release), markedly oversimplifies reality. Instead, we propose that mast cells are "tunable," by both genetic and environmental factors, such that, depending on the circumstances, the cell can be positioned phenotypically to express a wide spectrum of variation in the types, kinetics, and/or magnitude of its secretory functions.
View details for DOI 10.1146/annurev.immunol.21.120601.141025
View details for Web of Science ID 000228947000022
View details for PubMedID 15771585
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RabGEF1, a negative regulator of Ras signalling, mast cell activation and skin inflammation.
Novartis Foundation symposium
2005; 271: 115-124
Abstract
Mast cell activation induced by the aggregation of FcepsilonRI with IgE and antigen is mediated through the activation of multiple protein kinase cascades. This process induces mast cells to undergo degranulation, to synthesize and release lipid mediators, and to secrete multiple cytokines, chemokines and growth factors. We found that RabGEF1 (Rabex-5) binds to Ras and negatively regulates Ras activation and downstream effector pathways during FcepsilonRI-dependent mouse mast cell activation. Mast cells derived from RabGEF1-deficient mice exhibit significantly enhanced levels of degranulation, release of lipid mediators and secretion of cytokines in response to FcepsilonRI aggregation. RabGEF1 knockout mice have increased perinatal mortality and the mice that do survive develop severe skin inflammation and increased numbers of mast cells in the dermis, some of which exhibit morphological evidence of degranulation. These mice also show elevated concentrations of serum histamine and IgE. Thus, RabGEF1 is a negative regulator of Ras signalling and FcepsilonRI-dependent mast cell activation in vitro, and a lack of RabGEF1 results in the development of elevated numbers of mast cells in the skin and severe skin inflammation in vivo.
View details for PubMedID 16605131
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Using mast cell knock-in mice to analyze the roles of mast cells in allergic responses in vivo.
Chemical immunology and allergy
2005; 87: 179-197
Abstract
It is well established that mast cells are important effector cells mediating the acute phase of IgE-associated allergic disorders, but their roles in late phase reactions and chronic allergic inflammation are not well defined. Here we describe an experimental approach for analyzing mast cell functions in vivo by comparing the biological responses in wild-type mice, genetically mast cell-deficient mice, and 'mast cell knock-in mice' (mast cell-deficient mice selectively repaired of their mast cell deficiency). Studies using 'mast cell knock-in mice' have indicated that mast cells can contribute importantly to IgE-associated late phase reactions and to chronic allergic inflammation. Moreover, 'mast cell knock-in mice' containing adoptive-transferred mast cell populations with defined alterations in the expression of specific mast cell products can be used to characterize the mechanisms by which mast cells contribute to the expression of the response of interest.
View details for PubMedID 16107772
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Mast cells promote homeostasis by limiting endothelin-1-induced toxicity
NATURE
2004; 432 (7016): 512-516
Abstract
Endothelin-1 (ET-1) is a 21-amino-acid peptide, derived from vascular endothelial cells, with potent vasoconstrictor activity. ET-1 has been implicated in diverse physiological or pathological processes, including the vascular changes associated with sepsis. However, the factors that regulate ET-1-associated toxicity during bacterial infections, or in other settings, are not fully understood. Both the pathology associated with certain allergic and autoimmune disorders, and optimal host defence against bacterial and parasitic infections are mediated by mast cells. In vitro, mast cells can produce ET-1 (ref. 11), undergo ET-1-dependent and endothelin-A receptor (ET(A))-dependent activation, and release proteases that degrade ET-1 (ref. 14). Although the potential relationships between mast cells and the ET-1 system thus may be complex, the importance of interactions between ET-1 and mast cells in vivo is obscure. Here we show that ET(A)-dependent mast-cell activation can diminish both ET-1 levels and ET-1-induced pathology in vivo, and also can contribute to optimal survival during acute bacterial peritonitis. These findings identify a new biological function for mast cells: promotion of homeostasis by limiting the toxicity associated with an endogenous mediator.
View details for DOI 10.1038/nature03085
View details for Web of Science ID 000225322100049
View details for PubMedID 15543132
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RabGEF1 is a negative regulator of mast cell activation and skin inflammation
NATURE IMMUNOLOGY
2004; 5 (8): 844-852
Abstract
Mast cell activation induced by aggregation of Fc epsilon RI receptors with immunoglobulin E and antigen is mediated through the activation of multiple protein kinase cascades. Here we report that the regulatory protein RabGEF1 bound to Ras and negatively regulated Ras activation and its 'downstream' effector pathways in Fc epsilon RI-dependent mast cell activation. RabGEF1-deficient mast cells showed enhanced degranulation and release of lipid mediators and cytokines in response to Fc epsilon RI aggregation. RabGEF1-deficient mice developed severe skin inflammation and had increased numbers of mast cells. Thus, RabGEF1 is a negative regulator of Fc epsilon RI-dependent mast cell activation, and a lack of RabGEF1 results in the development of skin inflammation in vivo.
View details for DOI 10.1038/ni1093
View details for Web of Science ID 000222955600016
View details for PubMedID 15235600
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Immune sensitization in the skin is enhanced by antigen-independent effects of IgE
IMMUNITY
2004; 20 (4): 381-392
Abstract
Contact sensitivity responses require both effective immune sensitization following cutaneous exposure to chemical haptens and antigen-specific elicitation of inflammation upon subsequent hapten challenge. We report that antigen-independent effects of IgE antibodies can promote immune sensitization to haptens in the skin. Contact sensitivity was markedly impaired in IgE(-/-) mice but was restored by either transfer of sensitized cells from wild-type mice or administration of hapten-irrelevant IgE before sensitization. Moreover, IgE(-/-) mice exhibited impairment in the reduction of dendritic cell numbers in the epidermis after hapten exposure. Monomeric IgE has been reported to influence mast cell function. We observed diminished contact sensitivity in mice lacking FcepsilonRI or mast cells, and mRNA for several mast cell-associated genes was reduced in IgE(-/-) versus wild-type skin after hapten exposure. We speculate that levels of IgE normally present in mice favor immune sensitization via antigen-independent but FcepsilonRI-dependent effects on mast cells.
View details for Web of Science ID 000221442800005
View details for PubMedID 15084268
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Evidence that IgE molecules mediate a spectrum of effects on mast cell survival and activation via aggregation of the Fc epsilon RI
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
2003; 100 (22): 12911-12916
Abstract
We demonstrate that binding of different IgE molecules (IgEs) to their receptor, FcepsilonRI, induces a spectrum of activation events in the absence of a specific antigen and provide evidence that such activation reflects aggregation of FcepsilonRI. Highly cytokinergic IgEs can efficiently induce production of cytokines and render mast cells resistant to apoptosis in an autocrine fashion, whereas poorly cytokinergic IgEs induce these effects inefficiently. Highly cytokinergic IgEs seem to induce more extensive FcepsilonRI aggregation than do poorly cytokinergic IgEs, which leads to stronger mast cell activation and survival effects. These effects of both types of IgEs require Syk tyrosine kinase and can be inhibited by FcepsilonRI disaggregation with monovalent hapten. In hybridoma-transplanted mice, mucosal mast cell numbers correlate with serum IgE levels. Therefore, survival effects of IgE could contribute to the pathogenesis of allergic disease.
View details for DOI 10.1073/pnas.1735525100
View details for Web of Science ID 000186301100073
View details for PubMedID 14569021
View details for PubMedCentralID PMC240718
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Identification of A(3) receptor- and mast cell-dependent and -independent components of adenosine-mediated airway responsiveness in mice
JOURNAL OF IMMUNOLOGY
2003; 171 (1): 331-337
Abstract
Adenosine-induced bronchoconstriction is a well-recognized feature of atopic asthma. Adenosine acts through four different G protein-coupled receptors to produce a myriad of physiological effects. To examine the contribution of the A(3) adenosine receptor to adenosine-induced bronchoconstriction and to assess the contribution of mast cells to this process, we quantified airway responsiveness to aerosolized adenosine in wild-type, A(3) receptor-deficient, and mast cell-deficient mice. Compared with the robust airway responses elicited by adenosine in wild-type mice, both A(3)-deficient and mast cell-deficient mice exhibited a significantly attenuated response compared with their respective wild-type controls. Histological examination of the airways 4 h after adenosine exposure revealed extensive degranulation of airway mast cells as well as infiltration of neutrophils in wild-type mice, whereas these findings were much diminished in A(3)-deficient mice and were not different from those in PBS-treated controls. These data indicate that the airway responses to aerosolized adenosine in mice occur largely through A(3) receptor activation and that mast cells contribute significantly to these responses, but that activation of additional adenosine receptors on a cell type(s) other than mast cells also contributes to adenosine-induced airway responsiveness in mice. Finally, our findings indicate that adenosine exposure can result in A(3)-dependent airway inflammation, as reflected in neutrophil recruitment, as well as alterations in airway function.
View details for Web of Science ID 000183674400042
View details for PubMedID 12817015
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Severe anaphylactic reactions to glutamic acid decarboxylase (GAD) self peptides in NOD mice that spontaneously develop autoimmune type 1 diabetes mellitus.
BMC immunology
2003; 4: 2-?
Abstract
Insulin dependent (i.e., "type 1") diabetes mellitus (T1DM) is considered to be a T cell mediated disease in which TH1 and Tc autoreactive cells attack the pancreatic islets. Among the beta-cell antigens implicated in T1DM, glutamic acid decarboxylase (GAD) 65 appears to play a key role in the development of T1DM in humans as well as in non-obese diabetic (NOD) mice, the experimental model for this disease. It has been shown that shifting the immune response to this antigen from TH1 towards TH2, via the administration of GAD65 peptides to young NOD mice, can suppress the progression to overt T1DM. Accordingly, various protocols of "peptide immunotherapy" of T1DM are under investigation. However, in mice with experimental autoimmune encephalomyelitis (EAE), another autoimmune TH1 mediated disease that mimics human multiple sclerosis, anaphylactic shock can occur when the mice are challenged with certain myelin self peptides that initially were administered with adjuvant to induce the disease.Here we show that NOD mice, that spontaneously develop T1DM, can develop fatal anaphylactic reactions upon challenge with preparations of immunodominant GAD65 self peptides after immunization with these peptides to modify the development of T1DM.These findings document severe anaphylaxis to self peptide preparations used in an attempt to devise immunotherapy for a spontaneous autoimmune disease. Taken together with the findings in EAE, these results suggest that peptide therapies designed to induce a TH1 to TH2 shift carry a risk for the development of anaphylactic reactivity to the therapeutic peptides.
View details for PubMedID 12597780
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Multiple elements of the allergic arm of the immune response modulate autoimmune demyelination
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
2003; 100 (4): 1867-1872
Abstract
Analysis of mRNA from multiple sclerosis lesions revealed increased amounts of transcripts for several genes encoding molecules traditionally associated with allergic responses, including prostaglandin D synthase, histamine receptor type 1 (H1R), platelet activating factor receptor, Ig Fc epsilon receptor 1 (Fc epsilon RI), and tryptase. We now demonstrate that, in the animal model of multiple sclerosis, experimental autoimmune encephalomyelitis (EAE), mediated by T helper 1 (Th1) T cells, histamine receptor 1 and 2 (H1R and H2R) are present on inflammatory cells in brain lesions. Th1 cells reactive to myelin proteolipid protein expressed more H1R and less H2R than Th2 cells. Pyrilamine, an H1R antagonist, blocked EAE, and the platelet activating factor receptor antagonist CV6209 reduced the severity of EAE. EAE severity was also decreased in mice with disruption of the genes encoding Ig Fc gamma RIII or both Fc gamma RIII and Fc epsilon RI. Prostaglandin D synthase and tryptase transcripts were elevated in EAE brain. Taken together, these data reveal extensive involvement of elements of the immune response associated with allergy in autoimmune demyelination. The pathogenesis of demyelination must now be viewed as encompassing elements of both Th1 responses and "allergic" responses.
View details for DOI 10.1073/pnas.252777399
View details for Web of Science ID 000181073000077
View details for PubMedID 12576552
View details for PubMedCentralID PMC149925
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Transcriptional response of human mast cells stimulated via the Fc(epsilon)RI and identification of mast cells as a source of IL-11.
BMC immunology
2002; 3: 5-?
Abstract
In asthma and other allergic disorders, the activation of mast cells by IgE and antigen induces the cells to release histamine and other mediators of inflammation, as well as to produce certain cytokines and chemokines. To search for new mast cell products, we used complementary DNA microarrays to analyze gene expression in human umbilical cord blood-derived mast cells stimulated via the high-affinity IgE receptor (Fc(epsilon)RI).One to two hours after Fc(epsilon)RI-dependent stimulation, more than 2,400 genes (about half of which are of unknown function) exhibited 2-200 fold changes in expression. The transcriptional program included changes in the expression of IL-11 and at least 30 other cytokines and chemokines. Human mast cells secreted 130-529 pg of IL-11/106 cells by 6 h after stimulation with anti-IgE.Our initial analysis of the transcriptional program induced in in vitro-derived human mast cells stimulated via the Fc(epsilon)RI has identified many products that heretofore have not been associated with this cell type, but which may significantly influence mast cell function in IgE-associated host responses. We also have demonstrated that mast cells stimulated via the Fc(epsilon)RI can secrete IL-11. Based on the previously reported biological effects of IL-11, our results suggest that production of IL-11 may represent one link between IgE-dependent mast cell activation in subjects with allergic asthma and the development of a spectrum of structural changes in the airways of these individuals; such changes, collectively termed "airway remodeling," can constitute an important long term consequence of asthma.
View details for PubMedID 12079505
View details for PubMedCentralID PMC116674
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Mast cells derived from embryonic stem cells: A model system for studying the effects of genetic manipulations on mast cell development, phenotype, and function in vitro and in vivo
INTERNATIONAL JOURNAL OF HEMATOLOGY
2002; 75 (4): 345-349
Abstract
Large quantities of highly enriched populations of mast cells can be generated from mouse embryonic stem (ES) cells using an in vitro differentiation system. These embryonic stem cell-derived mast cells (ESMCs) exhibit many similarities to mouse bone marrow-derived cultured mast cells (BMCMCs), including the abilities to survive and to orchestrate immunologically specific immunoglobulin E (IgE)-dependent reactions in vivo after transplantation into genetically mast cell-deficient KitW/KitW-v mice. Coupled with the current spectrum of techniques for genetically manipulating ES cells, ESMCs represent a unique model system to analyze the effects of specific alterations in gene structure, expression, or function, including embryonic lethal mutations, on mast cell development, phenotype, and function in vitro and in vivo.
View details for Web of Science ID 000175713200001
View details for PubMedID 12041662
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Analyzing the roles of mast cells and basophils in host defense and other biological responses
INTERNATIONAL JOURNAL OF HEMATOLOGY
2002; 75 (4): 363-369
Abstract
The sudden and systemic activation of mediator release from mast cells and basophils that can occur when some sensitized subjects are challenged by minute amounts of specific antigen (eg, from an insect sting or peanuts) can result in fatal anaphylaxis, a reaction that arguably represents the most grotesque imbalance between the cost and benefit of an immune response. Why then do mast cells and basophils continue to exist and, in the case of mast cells, populate almost all vascularized tissues? This review will consider the roles of mast cells and basophils in health and disease, emphasizing particularly their proven or potential functions in host defense. We will also describe briefly some approaches to investigate mast cell and basophil functions in vivo, including the use of mast cells generated directly from embryonic stem cells in vitro.
View details for Web of Science ID 000175713200004
View details for PubMedID 12041665
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Dexamethasone suppresses anti-IgE-induced production of interleukin-11 from cultured human mast cells
FEDERATION AMER SOC EXP BIOL. 2002: A1241–A1241
View details for Web of Science ID 000174593902854
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Evidence that stem cell factor regulates TrkC expression in mast cells and in the central nervous system
FEDERATION AMER SOC EXP BIOL. 2002: A1239–A1239
View details for Web of Science ID 000174593902843
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Regulation of mast cell survival by IgE
IMMUNITY
2001; 14 (6): 791-800
Abstract
Mast cells play critical roles in hypersensitivity and in defense against certain parasites. We provide evidence that mouse mast cell survival and growth are promoted by monomeric IgE binding to its high-affinity receptor, Fc epsilon RI. Monomeric IgE does not promote DNA synthesis but suppresses the apoptosis induced by growth factor deprivation. This antiapoptotic effect occurs in parallel with IgE-induced increases in Fc epsilon RI surface expression but requires the continuous presence of IgE. This process does not involve the FasL/Fas death pathway or several Bcl-2 family proteins and induces a distinctly different signal than Fc epsilon RI cross-linking. The ability of IgE to enhance mast cell survival and Fc epsilon RI expression may contribute to amplified allergic reactions.
View details for Web of Science ID 000169495100014
View details for PubMedID 11420048
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Allergy to self: An unexpected immune response in EAE
LIPPINCOTT WILLIAMS & WILKINS. 2001: A94
View details for Web of Science ID 000168270600246
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An unexpected version of horror autotoxicus: anaphylactic shock to a self peptide
NATURE IMMUNOLOGY
2001; 2 (3): 216-222
Abstract
EAE can refer either to experimental autoimmune encephalomyelitis or experimental allergic encephalomyelitis. Although EAE is classically a prototypic T helper 1 (TH1) cell-mediated autoimmune disease, it can also be induced by TH2 cells. Characteristically, the most severe manifestation of allergy, anaphylaxis, is associated with exposure to a foreign antigen that is often derived from medication, insect venom or food. We report here that, after self-tolerance to myelin is destroyed, anaphylaxis may be triggered by a self-antigen, in this case a myelin peptide. "Horror autotoxicus", which was initially described by Ehrlich, may not only include autoimmunity to self, it may also encompass immediate hypersensitivity to self, which leads to shock and rapid death.
View details for Web of Science ID 000167413800013
View details for PubMedID 11224520
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Roles of mast cells and basophils in innate and acquired immunity
CURRENT OPINION IN IMMUNOLOGY
2000; 12 (6): 624-631
Abstract
There have been several recent advances in knowledge about mast cells and basophils in immune responses, of which some are particularly important: a role has been found for heparin in the storage of certain proteases and other mediators in mast cell cytoplasmic granules; an important role for mast cells in the development of several chronic aspects of an asthma model in mice has been discovered; and a new approach has been developed, based on the generation of mast cells from embryonic stem cells in vitro, to investigate mast cell function in vitro or in vivo.
View details for Web of Science ID 000165218000003
View details for PubMedID 11102764
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In vivo immunological function of mast cells derived from embryonic stem cells: An approach for the rapid analysis of even embryonic lethal mutations in adult mice in vivo
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
2000; 97 (16): 9186-9190
Abstract
An important goal of tissue engineering is to achieve reconstitution of specific functionally active cell types by transplantation of differentiated cell populations derived from normal or genetically altered embryonic stem cells in vitro. We find that mast cells derived in vitro from wild-type or genetically manipulated embryonic stem cells can survive and orchestrate immunologically specific IgE-dependent reactions after transplantation into mast cell-deficient Kit(W)/Kit(W-v) mice. These findings define a unique approach for analyzing the effects of mutations of any genes that are expressed in mast cells, including embryonic lethal mutations, in vitro or in vivo.
View details for Web of Science ID 000088608000077
View details for PubMedID 10908668
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A role for Bax in the regulation of apoptosis in mouse mast cells
JOURNAL OF INVESTIGATIVE DERMATOLOGY
2000; 114 (6): 1205-1206
View details for Web of Science ID 000087365800022
View details for PubMedID 10844568