Honors & Awards


  • K99/R00 pathway to independence award (Score 10/10), National Institute of Health (NIH) (2018)
  • Swiss National Foundation (SNF) award, Swiss National Foundation (2013)
  • MedAlumni young investigator award, University of Zurich (2012)

Professional Education


  • PhD, Rockefeller University, Molecular Immunology (2018)
  • MSc, Rockefeller University, Master of Clinical Investigation (2017)
  • Board Certification Exam, Switzerland (SGIM), Medical Oncology (2011)
  • Board Certification Exam, Switzerland (SGIM), Internal Medicine (2008)
  • MD, University of Zurich, Switzerland, Medical Doctor (2005)

All Publications


  • A phase I/IIa study of the mRNA-based cancer immunotherapy CV9201 in patients with stage IIIB/IV non-small cell lung cancer. Cancer immunology, immunotherapy : CII Sebastian, M., Schroder, A., Scheel, B., Hong, H. S., Muth, A., von Boehmer, L., Zippelius, A., Mayer, F., Reck, M., Atanackovic, D., Thomas, M., Schneller, F., Stohlmacher, J., Bernhard, H., Groschel, A., Lander, T., Probst, J., Strack, T., Wiegand, V., Gnad-Vogt, U., Kallen, K., Hoerr, I., von der Muelbe, F., Fotin-Mleczek, M., Knuth, A., Koch, S. D. 2019

    Abstract

    CV9201 is an RNActive-based cancer immunotherapy encoding five non-small cell lung cancer-antigens: New York esophageal squamous cell carcinoma-1, melanoma antigen family C1/C2, survivin, and trophoblast glycoprotein. In a phase I/IIa dose-escalation trial, 46 patients with locally advanced (n=7) or metastatic (n=39) NSCLC and at least stable disease after first-line treatment received five intradermal CV9201 injections (400-1600g of mRNA). The primary objective of the trial was to assess safety. Secondary objectives included assessment of antibody and ex vivo T cell responses against the five antigens, and changes in immune cell populations. All CV9201 dose levels were well-tolerated and the recommended dose for phase IIa was 1600g. Most AEs were mild-to-moderate injection site reactions and flu-like symptoms. Three (7%) patients had grade 3 related AEs. No related grade 4/5 or related serious AEs occurred. In phase IIa, antigen-specific immune responses against ≥1 antigen were detected in 63% of evaluable patients after treatment. The frequency of activated IgD+CD38hi B cells increased>twofold in 18/30 (60%) evaluable patients. 9/29 (31%) evaluable patients in phase IIa had stable disease and 20/29 (69%) had progressive disease. Median progression-free and overall survival were 5.0months (95% CI 1.8-6.3) and 10.8months (8.1-16.7) from first administration, respectively. Two- and 3-year survival rates were 26.7% and 20.7%, respectively. CV9201 was well-tolerated and immune responses could be detected after treatment supporting further clinical investigation.

    View details for PubMedID 30770959

  • beta6 -Integrin serves as a novel serum tumor marker for colorectal carcinoma. International journal of cancer Bengs, S., Becker, E., Busenhart, P., Spalinger, M. R., Raselli, T., Kasper, S., Lang, S., Atrott, K., Mamie, C., Vavricka, S. R., von Boehmer, L., Knuth, A., Tuomisto, A., Makinen, M. J., Hruz, P., Turina, M., Rickenbacher, A., Petrowsky, H., Weber, A., Frei, P., Halama, M., Jenkins, G., Sheppard, D., Croner, R. S., Christoph, J., Britzen-Laurent, N., Naschberger, E., Schellerer, V., Sturzl, M., Fried, M., Rogler, G., Scharl, M. 2019

    Abstract

    Colorectal cancer (CRC) is one of the leading causes of cancer-related deaths worldwide and the need for novel biomarkers and therapeutic strategies to improve diagnosis and surveillance is obvious. This study aims to identify beta6-integrin (ITGB6) as a novel serum tumor marker for diagnosis, prognosis, and surveillance of CRC. ITGB6 serum levels were validated in retro- and prospective CRC patient cohorts. ITGB6 serum levels were analyzed by ELISA. Using an initial cohort of 60 CRC patients, we found that ITGB6 is present in the serum of CRC, but not in non-CRC control patients. A cut-off of ≥2ng /mL ITGB6 reveals 100% specificity for the presence of metastatic CRC. In an enlarged study cohort of 269 CRC patients, ITGB6 predicted the onset of metastatic disease and was associated with poor prognosis. Those data were confirmed in an independent, prospective cohort consisting of 40 CRC patients. To investigate whether ITGB6 can also be used for tumor surveillance, serum ITGB6-levels were assessed in 26 CRC patients, pre- and post-surgery, as well as during follow-up visits. After complete tumor resection, ITGB6 serum levels declined completely. During follow-up, a new rise in ITGB6 serum levels indicated tumor recurrence or the onset of new metastasis as confirmed by CT scan. ITGB6 was more accurate for prognosis of advanced CRC and for tumor surveillance as the established marker carcinoembryonic antigen (CEA). Our findings identify ITGB6 as a novel serum marker for diagnosis, prognosis, and surveillance of advanced CRC. This might essentially contribute to an optimized patient care. This article is protected by copyright. All rights reserved.

    View details for PubMedID 30653264

  • Beta-6-Integrin serves as a novel tumor marker and therapeutic target for colorectal carcinoma Bengs, S., Becker, E., Spalinger, M. R., Raselli, T., Kasper, S., Lang, S., Atrott, K., Mamie, C., Britzen-Laurent, N., von Boehmer, L., Knuth, A., Tuomisto, A., Makinen, M. J., Hruz, P., Turina, M., Rickenbacher, A., Petrowsky, H., Weber, A., Frei, P., Vavricka, S. R., Halama, M., Croner, R. S., Christoph, J., Jenkins, G., Sheppard, D., Stuerzl, M., Fried, M., Rogler, G., Scharl, M. E M H SWISS MEDICAL PUBLISHERS LTD. 2017: 9S
  • Structure of a Natively-glycosylated HIV-1 Env Reveals a New Mode for VH1-2 Antibody Recognition of the CD4 Binding Site Relevant to Vaccine Design Gristick, H., von Boehmer, L., West, A., Schamber, M., Gazumyan, A., Golijanin, J., Seaman, M., Faetkenheuer, G., Klein, F., Nussenzweig, M., Bjorkman, P. MARY ANN LIEBERT, INC. 2016: 62
  • Sequencing and cloning of antigen-specific antibodies from mouse memory B cells. Nature protocols von Boehmer, L., Liu, C., Ackerman, S., Gitlin, A. D., Wang, Q., Gazumyan, A., Nussenzweig, M. C. 2016; 11 (10): 1908–23

    Abstract

    Methods to identify genes encoding immunoglobulin heavy and light chains from single B lymphocytes vary in efficiency, error rate and practicability. Here we describe a protocol to sequence and clone the variable antibody region of single antigen-specific mouse memory B cells for antibody production. After purification, antigen-specific mouse memory B cells are first single-cell-sorted by fluorescence-activated cell sorting (FACS), and V(D)J transcripts are amplified by RT-PCR. Fragments are then combined with linearized expression vectors, assembled in vitro as part of a sequence- and ligation-independent cloning (SLIC) reaction and then transformed into Escherichia coli. Purified vectors can then be used to produce monoclonal antibodies in HEK293E suspension cells. This protocol improves the amplification efficiency of antibody variable genes and accelerates the cloning workflow. Antibody sequences will be available in 3-4 d, and microgram to milligram amounts of antibodies are produced within 14 d. The new protocol should be useful for addressing fundamental questions about antigen-specific memory B cell responses, as well as for characterizing antigen-specific antibodies.

    View details for DOI 10.1038/nprot.2016.102

    View details for PubMedID 27658009

  • Short Peptide Vaccine Induces CD4+ T Helper Cells in Patients with Different Solid Cancers. Cancer immunology research Gross, S., Lennerz, V., Gallerani, E., Mach, N., Böhm, S., Hess, D., von Boehmer, L., Knuth, A., Ochsenbein, A., Gnad-Vogt, U., Forssmann, U., Woelfel, T., Kaempgen, E. 2016; 4 (1): 18–25

    Abstract

    Previous cancer vaccination trials often aimed to activate CD8(+) cytotoxic T-cell (CTL) responses with short (8-10mer) peptides and targeted CD4(+) helper T cells (TH) with HLA class II-binding longer peptides (12-16 mer) that were derived from tumor antigens. Accordingly, a study of immunomonitoring focused on the detection of CTL responses to the short, and TH responses to the long, peptides. The possible induction of concurrent TH responses to short peptides was widely neglected. In a recent phase I vaccination trial, 53 patients with different solid cancers were vaccinated with EMD640744, a cocktail of five survivin-derived short (9- or 10-mer) peptides in Montanide ISA 51VG. We monitored 49 patients and found strong CD8(+) T-cell responses in 63% of the patients. In addition, we unexpectedly found CD4(+) TH cell responses against at least two of the five short peptides in 61% (23/38) of the patients analyzed. The two peptides were recognized by HLA-DP4- and HLA-DR-restricted TH1 cells. Some short peptide-reactive (sp)CD4 T cells showed high functional avidity. Here, we show that a short peptide vaccine is able to activate a specific CD4(+) T-cell repertoire in many patients, facilitating a strong combined CD4(+)/CD8(+) T-cell response.

    View details for DOI 10.1158/2326-6066.CIR-15-0105

    View details for PubMedID 26563311

  • Independent Roles of Switching and Hypermutation in the Development and Persistence of B Lymphocyte Memory. Immunity Gitlin, A. D., von Boehmer, L., Gazumyan, A., Shulman, Z., Oliveira, T. Y., Nussenzweig, M. C. 2016; 44 (4): 769–81

    Abstract

    Somatic hypermutation (SHM) and class-switch recombination (CSR) increase the affinity and diversify the effector functions of antibodies during immune responses. Although SHM and CSR are fundamentally different, their independent roles in regulating B cell fate have been difficult to uncouple because a single enzyme, activation-induced cytidine deaminase (encoded by Aicda), initiates both reactions. Here, we used a combination of Aicda and antibody mutant alleles that separate the effects of CSR and SHM on polyclonal immune responses. We found that class-switching to IgG1 biased the fate choice made by B cells, favoring the plasma cell over memory cell fate without significantly affecting clonal expansion in the germinal center (GC). In contrast, SHM reduced the longevity of memory B cells by creating polyreactive specificities that were selected against over time. Our data define the independent contributions of SHM and CSR to the generation and persistence of memory in the antibody system.

    View details for DOI 10.1016/j.immuni.2016.01.011

    View details for PubMedID 26944202

    View details for PubMedCentralID PMC4838502

  • Natively glycosylated HIV-1 Env structure reveals new mode for antibody recognition of the CD4-binding site. Nature structural & molecular biology Gristick, H. B., von Boehmer, L., West, A. P., Schamber, M., Gazumyan, A., Golijanin, J., Seaman, M. S., Fätkenheuer, G., Klein, F., Nussenzweig, M. C., Bjorkman, P. J. 2016; 23 (10): 906–15

    Abstract

    HIV-1 vaccine design is informed by structural studies elucidating mechanisms by which broadly neutralizing antibodies (bNAbs) recognize and/or accommodate N-glycans on the trimeric envelope glycoprotein (Env). Variability in high-mannose and complex-type Env glycoforms leads to heterogeneity that usually precludes visualization of the native glycan shield. We present 3.5-Å- and 3.9-Å-resolution crystal structures of the HIV-1 Env trimer with fully processed and native glycosylation, revealing a glycan shield of high-mannose and complex-type N-glycans, which we used to define complete epitopes of two bNAbs. Env trimer was complexed with 10-1074 (against the V3-loop) and IOMA, a new CD4-binding site (CD4bs) antibody. Although IOMA derives from VH1-2*02, the germline gene of CD4bs-targeting VRC01-class bNAbs, its light chain lacks the short CDRL3 that defines VRC01-class bNAbs. Thus IOMA resembles 8ANC131-class/VH1-46-derived CD4bs bNAbs, which have normal-length CDRL3s. The existence of bNAbs that combine features of VRC01-class and 8ANC131-class antibodies has implications for immunization strategies targeting VRC01-like bNAbs.

    View details for DOI 10.1038/nsmb.3291

    View details for PubMedID 27617431

    View details for PubMedCentralID PMC5127623

  • Immunization for HIV-1 Broadly Neutralizing Antibodies in Human Ig Knockin Mice. Cell Dosenovic, P., von Boehmer, L., Escolano, A., Jardine, J., Freund, N. T., Gitlin, A. D., McGuire, A. T., Kulp, D. W., Oliveira, T., Scharf, L., Pietzsch, J., Gray, M. D., Cupo, A., van Gils, M. J., Yao, K. H., Liu, C., Gazumyan, A., Seaman, M. S., Björkman, P. J., Sanders, R. W., Moore, J. P., Stamatatos, L., Schief, W. R., Nussenzweig, M. C. 2015; 161 (7): 1505–15

    Abstract

    A subset of individuals infected with HIV-1 develops broadly neutralizing antibodies (bNAbs) that can prevent infection, but it has not yet been possible to elicit these antibodies by immunization. To systematically explore how immunization might be tailored to produce them, we generated mice expressing the predicted germline or mature heavy chains of a potent bNAb to the CD4 binding site (CD4bs) on the HIV-1 envelope glycoprotein (Env). Immunogens specifically designed to activate B cells bearing germline antibodies are required to initiate immune responses, but they do not elicit bNAbs. In contrast, native-like Env trimers fail to activate B cells expressing germline antibodies but elicit bNAbs by selecting for a restricted group of light chains bearing specific somatic mutations that enhance neutralizing activity. The data suggest that vaccination to elicit anti-HIV-1 antibodies will require immunization with a succession of related immunogens.

    View details for DOI 10.1016/j.cell.2015.06.003

    View details for PubMedID 26091035

    View details for PubMedCentralID PMC4604566

  • Tumor imaging in patients with advanced tumors using a new (99m) Tc-radiolabeled vitamin B12 derivative. Journal of nuclear medicine : official publication, Society of Nuclear Medicine Sah, B. R., Schibli, R., Waibel, R., von Boehmer, L., Bläuenstein, P., Nexo, E., Johayem, A., Fischer, E., Müller, E., Soyka, J. D., Knuth, A. K., Haerle, S. K., Schubiger, P. A., Schaefer, N. G., Burger, I. A. 2014; 55 (1): 43–49

    Abstract

    Targeting cancer cells with vitamin B12 (cobalamin) is hampered by unwanted physiologic tissue uptake mediated by transcobalamin. Adhering to good manufacturing practice, we have developed a new (99m)Tc-cobalamin derivative ((99m)Tc(CO)3-[(4-amido-butyl)-pyridin-2-yl-methyl-amino-acetato] cobalamin, (99m)Tc-PAMA-cobalamin). The derivative shows no binding to transcobalamin but is recognized by haptocorrin, a protein present in the circulation and notably expressed in many tumor cells. In this prospective study, we investigated cancer-specific uptake of (99m)Tc-PAMA-cobalamin in 10 patients with various metastatic tumors.Ten patients with biopsy-proven metastatic cancer were included. Dynamic imaging was started immediately after injection of 300-500 MBq of (99m)Tc-PAMA-cobalamin, and whole-body scintigrams were obtained at 10, 30, 60, 120, and 240 min and after 24 h. The relative tumor activity using SPECT/CT over the tumor region after 4 h was measured in comparison to disease-free lung parenchyma. Patients 3-10 received between 20 and 1,000 μg of cobalamin intravenously before injection of (99m)Tc-PAMA-cobalamin. The study population comprised 4 patients with adenocarcinomas of the lung, 3 with squamous cell carcinomas of the hypopharyngeal region, 1 with prostate adenocarcinoma, 1 with breast, and 1 with colon adenocarcinoma.The median age of the study group was 61 ± 11 y. Six of 10 patients showed positive tumor uptake on (99m)Tc-PAMA-cobalamin whole-body scintigraphy. The scan was positive in 1 patient with colon adenocarcinoma, in 3 of 4 lung adenocarcinomas, in 1 of 3 hypopharyngeal squamous cell carcinomas, and in 1 breast adenocarcinoma. Renal uptake was between 1% and 3% for the left kidney. Predosing with cobalamin increased the tumor uptake and improved blood-pool clearance. The best image quality was achieved with a predose of 20-100 ug of cold cobalamin. The mean patient dose was 2.7 ± 0.9 mSv/patient.To our knowledge, we report for the first time on (99m)Tc-PAMA-cobalamin imaging in patients with metastatic cancer disease and show that tumor targeting is feasible.

    View details for DOI 10.2967/jnumed.113.122499

    View details for PubMedID 24337606

  • Immunologic response to the survivin-derived multi-epitope vaccine EMD640744 in patients with advanced solid tumors. Cancer immunology, immunotherapy : CII Lennerz, V., Gross, S., Gallerani, E., Sessa, C., Mach, N., Boehm, S., Hess, D., von Boehmer, L., Knuth, A., Ochsenbein, A. F., Gnad-Vogt, U., Zieschang, J., Forssmann, U., Woelfel, T., Kaempgen, E. 2014; 63 (4): 381–94

    Abstract

    Survivin is a member of the inhibitor-of-apoptosis family. Essential for tumor cell survival and overexpressed in most cancers, survivin is a promising target for anti-cancer immunotherapy. Immunogenicity has been demonstrated in multiple cancers. Nonetheless, few clinical trials have demonstrated survivin-vaccine-induced immune responses.This phase I trial was conducted to test whether vaccine EMD640744, a cocktail of five HLA class I-binding survivin peptides in Montanide(®) ISA 51 VG, promotes anti-survivin T-cell responses in patients with solid cancers. The primary objective was to compare immunologic efficacy of EMD640744 at doses of 30, 100, and 300 μg. Secondary objectives included safety, tolerability, and clinical efficacy.In total, 49 patients who received ≥2 EMD640744 injections with available baseline- and ≥1 post-vaccination samples [immunologic-diagnostic (ID)-intention-to-treat] were analyzed by ELISpot- and peptide/MHC-multimer staining, revealing vaccine-activated peptide-specific T-cell responses in 31 patients (63 %). This cohort included the per study protocol relevant ID population for the primary objective, i.e., T-cell responses by ELISpot in 17 weeks following first vaccination, as well as subjects who discontinued the study before week 17 but showed responses to the treatment. No dose-dependent effects were observed. In the majority of patients (61 %), anti-survivin responses were detected only after vaccination, providing evidence for de novo induction. Best overall tumor response was stable disease (28 %). EMD640744 was well tolerated; local injection-site reactions constituted the most frequent adverse event.Vaccination with EMD640744 elicited T-cell responses against survivin peptides in the majority of patients, demonstrating the immunologic efficacy of EMD640744.

    View details for DOI 10.1007/s00262-013-1516-5

    View details for PubMedID 24487961

  • Spontaneous peripheral T-cell responses toward the tumor-associated antigen cyclin D1 in patients with clear cell renal cell carcinoma. Cancer immunology research Dannenmann, S. R., Hermanns, T., Bransi, A., Matter, C., von Boehmer, L., Stevanovic, S., Schraml, P., Moch, H., Knuth, A., van den Broek, M. 2013; 1 (5): 288–95

    Abstract

    Renal cell carcinoma (RCC) is a heterogeneous group of kidney cancers with clear cell RCC (ccRCC) as the major subgroup. To expand the number of clinically relevant tumor-associated antigens (TAA) that can be targeted by immunotherapy, we analyzed samples from 23 patients with primary ccRCC for the expression and immunogenicity of various TAAs. We found high-frequency expression of MAGE-A9 and NY-ESO-1 in 36% and 55% of samples, respectively, and overexpression of PRAME, RAGE-1, CA-IX, Cyclin D1, ADFP, C-MET, and RGS-5 in many of the tumor samples. We analyzed the blood of patients with HLA-A2(+) ccRCC for the presence of CD8(+) T cells specific for TAA-derived HLA-A2-restricted peptides and found spontaneous responses to cyclin D1 in 5 of 6 patients with Cyclin D1-positive tumors. Cyclin D1-specific CD8(+) T cells secreted TNF-α, IFN-γ, and interleukin-2 (IL-2), and degranulated, indicating the presence of polyfunctional tumor-specific CD8(+) T cells in the blood of these patients with ccRCC. The high frequency (43%) of Cyclin D1 overexpression and the presence of functional cyclin D1-specific T cells in 83% of these patients with ccRCC suggest that cyclin D1 may be a target for immunotherapeutic strategies.

    View details for DOI 10.1158/2326-6066.CIR-13-0113

    View details for PubMedID 24777966

  • A novel human-derived antibody against NY-ESO-1 improves the efficacy of chemotherapy. Cancer immunity Gupta, A., Nuber, N., Esslinger, C., Wittenbrink, M., Treder, M., Landshammer, A., Noguchi, T., Kelly, M., Gnjatic, S., Ritter, E., von Boehmer, L., Nishikawa, H., Shiku, H., Old, L., Ritter, G., Knuth, A., van den Broek, M. 2013; 13: 3

    Abstract

    We investigated whether antibodies against intracellular tumor-associated antigens support tumor-specific immunity when administered together with a treatment that destroys the tumor. We propose that released antigens form immune complexes with the antibodies, which are then efficiently taken up by dendritic cells. We cloned the first human monoclonal antibodies against the Cancer/Testis (CT) antigen, NY-ESO-1. We tested whether the monoclonal anti-NY-ESO-1 antibody (12D7) facilitates cross-presentation of a NY-ESO-1-derived epitope by dendritic cells to human CD8+ T cells, and whether this results in the maturation of dendritic cells in vitro. We investigated the efficacy of 12D7 in combination with chemotherapy using BALB/c mice bearing syngeneic CT26 tumors that express intracellular NY-ESO-1. Human dendritic cells that were incubated with NY-ESO-1:12D7 immune complexes efficiently stimulated NY-ESO-1(157-165)/HLA-A2-specific human CD8+ T cells to produce interferon-γ, whereas NY-ESO-1 alone did not. Furthermore, the incubation of dendritic cells with NY-ESO-1:12D7 immune complexes resulted in the maturation of dendritic cells. Treatment of BALB/c mice that bear CT26/NY-ESO-1 tumors with 5-fluorouracil (5-FU) plus 12D7 was significantly more effective than chemotherapy alone. We propose systemic injection of monoclonal antibodies (mAbs) against tumor-associated antigens plus a treatment that promotes the local release of those antigens resulting in immune complex formation as a novel therapeutic modality for cancer.

    View details for PubMedID 23390374

    View details for PubMedCentralID PMC3559191

  • MAGE-C1/CT7 spontaneously triggers a CD4+ T-cell response in multiple myeloma patients. Leukemia Nuber, N., Curioni-Fontecedro, A., Dannenmann, S. R., Matter, C., von Boehmer, L., Atanackovic, D., Knuth, A., van den Broek, M. 2013; 27 (8): 1767–69

    View details for DOI 10.1038/leu.2013.31

    View details for PubMedID 23429573

  • Radiotherapy of human sarcoma promotes an intratumoral immune effector signature. Clinical cancer research : an official journal of the American Association for Cancer Research Sharma, A., Bode, B., Studer, G., Moch, H., Okoniewski, M., Knuth, A., von Boehmer, L., van den Broek, M. 2013; 19 (17): 4843–53

    Abstract

    The tumor immune microenvironment plays a crucial role in the development and progression of cancer. Sarcomas are a group of heterogeneous soft tissue malignancies that are often treated with radiotherapy as a part of the treatment concept. There is increasing evidence that radiotherapy leads to alterations in the tumor microenvironment, particularly with respect to the immune infiltrate. This study has been carried out to develop a better understanding of such changes following radiotherapy.We retrospectively analyzed the expression of 35 immune response-related genes by quantitative reverse transcription PCR analysis and immunohistochemistry on paired formalin-fixed paraffin-embedded tumor samples from 38 sarcoma patients before and after radiotherapy.We observed that radiotherapy results in a significant upregulation of several immune effectors and cancer-testis antigens and a concomitant downregulation of immune suppressors, indicating that radiotherapy may support the immune defense in sarcomas.These novel findings may have implications for the design of therapeutic regimens which exploite the immune system in sarcoma patients by combining standard radiotherapy with immunotherapeutic strategies.

    View details for DOI 10.1158/1078-0432.CCR-13-0352

    View details for PubMedID 23861514

  • Tumor-associated macrophages subvert T-cell function and correlate with reduced survival in clear cell renal cell carcinoma. Oncoimmunology Dannenmann, S. R., Thielicke, J., Stöckli, M., Matter, C., von Boehmer, L., Cecconi, V., Hermanns, T., Hefermehl, L., Schraml, P., Moch, H., Knuth, A., van den Broek, M. 2013; 2 (3): e23562

    Abstract

    Although malignant cells can be recognized and controlled by the immune system, in patients with clinically apparent cancer immunosurveillance has failed. To better understand local immunoregulatory processes that impact on cancer progression, we correlated intratumoral immunological profiles with the survival of patients affected by primary clear cell renal cell carcinoma (ccRCC). A retrospective analysis of 54 primary ccRCC samples for 31 different immune response-related transcripts, revealed a negative correlation of CD68 (a marker of tumor-associated macrophages, TAMs) and FOXP3 (a marker of regulatory T cells, Tregs) with survival. The subsequent analysis of 12 TAM-related transcripts revealed an association between the genes coding for CD163, interferon regulatory factor 4 (IRF4) and fibronectin 1 (FN1), all of which have been linked to the M2 TAM phenotype, with reduced survival and increased tumor stage, whereas the opposite was the case for the M1-associated gene coding for inducible nitric oxide synthetase (iNOS). The M2 signature of (CD68+) TAMs was found to correlate with CD163 expression, as determined in prospectively collected fresh ccRCC tissue samples. Upon co-culture with autologous tumor cells, CD11b+ cells isolated from paired blood samples expressed CD163 and other M2-associated proteins, suggesting that the malignant cells promote the accumulation of M2 TAMs. Furthermore, the tumor-associated milieu as well as isolated TAMs induced the skewing of autologous, blood-derived CD4+ T cells toward a more immunosuppressive phenotype, as shown by decreased production of effector cytokines, increased production of interleukin-10 (IL-10) and enhanced expression of the co-inhibitory molecules programmed death 1 (PD-1) and T-cell immunoglobulin mucin 3 (TIM-3). Taken together, our data suggest that ccRCC progressively attracts macrophages and induces their skewing into M2 TAMs, in turn subverting tumor-infiltrating T cells such that immunoregulatory functions are increased at the expense of effector functions.

    View details for DOI 10.4161/onci.23562

    View details for PubMedID 23687622

    View details for PubMedCentralID PMC3655740

  • NY-ESO-1-specific immunological pressure and escape in a patient with metastatic melanoma. Cancer immunity von Boehmer, L., Mattle, M., Bode, P., Landshammer, A., Schäfer, C., Nuber, N., Ritter, G., Old, L., Moch, H., Schäfer, N., Jäger, E., Knuth, A., van den Broek, M. 2013; 13: 12

    Abstract

    During cancer progression, malignant cells may evade immunosurveillance. However, evidence for immunological escape in humans is scarce. We report here the clinical course of a melanoma patient whose initial tumor was positive for the antigens NY-ESO-1, MAGE-C1, and Melan-A. Upon immunization with a recombinant vaccinia/fowlpox NY-ESO-1 construct, the patient experienced a mixed clinical response and spreading of the NY-ESO-1 epitopes in the CD4+ T cell compartment. After NY-ESO-1 protein + CpG immunization, the patient's anti-NY-ESO-1 IgG response increased. Over the following years, progressing lesions were resected and found to be NY-ESO-1-negative while being positive for MAGE-C1, Melan-A, and MHC-I. The fatal, inoperable brain metastasis was analyzed after his death and also proved to be NY-ESO-1-negative, while being positive for MAGE-C1 and Melan-A, as well as MHC-I. We propose that cancer control and cancer escape in this patient were governed by NY-ESO-1-specific immunological pressure. Our findings provide evidence for the existence of immunoediting and immunoescape in this cancer patient.

    View details for PubMedID 23882157

    View details for PubMedCentralID PMC3718732

  • Radiotherapy supports protective tumor-specific immunity. Oncoimmunology Gupta, A., Sharma, A., von Boehmer, L., Surace, L., Knuth, A., van den Broek, M. 2012; 1 (9): 1610–11

    Abstract

    Radiotherapy is an important therapeutic option for the treatment of cancer. Growing evidence indicates that, besides inducing an irreversible DNA damage, radiotherapy promotes tumor-specific immune response, which significantly contribute to therapeutic efficacy. We postulate that radiotherapy activates tumor-associated dendritic cells, thus changing the tolerogenic tumor environment into an immunogenic one.

    View details for DOI 10.4161/onci.21478

    View details for PubMedID 23264910

    View details for PubMedCentralID PMC3525619

  • Immunosuppression and lung cancer of donor origin after bilateral lung transplantation. Lung cancer (Amsterdam, Netherlands) von Boehmer, L., Draenert, A., Jungraithmayr, W., Inci, I., Niklaus, S., Boehler, A., Hofer, M., Stahel, R., Soltermann, A., van den Broek, M., Weder, W., Knuth, A. 2012; 76 (1): 118–22

    Abstract

    Analysis of databases from transplant recipients revealed a 3-5 fold higher risk to develop de novo malignancies under continued immunosuppression. The underlying mechanisms are poorly understood. Here we describe a patient who received a bilateral lung transplantation for end-stage 'usual interstitial pneumonia' (UIP) resulting in idiopathic lung fibrosis. The recipient presented with a non-small cell lung carcinoma (NSCLC) in the donor lung 7 months later. Molecular and immunological typing of the tumor revealed a cancer of donor origin with a prominent intratumoral immune cell infiltrate without detectable effector function. This is a unique case of de novo outgrowth of a NSCLC of donor origin under continued immunosuppression, supporting the concept of tumor immunosurveillance in vivo.

    View details for DOI 10.1016/j.lungcan.2011.10.001

    View details for PubMedID 22088939

  • New insight into hyperthermic intraperitoneal chemotherapy: induction of oxidative stress dramatically enhanced tumor killing in in vitro and in vivo models. Annals of surgery Lehmann, K., Rickenbacher, A., Jang, J. H., Oberkofler, C. E., Vonlanthen, R., von Boehmer, L., Humar, B., Graf, R., Gertsch, P., Clavien, P. A. 2012; 256 (5): 730–37; discussion 737–38

    Abstract

    The aim of hyperthermic intraperitoneal chemotherapy (HIPEC) is to eradicate microscopic residual tumor after radical surgical tumor excision in patients with peritoneal carcinomatosis. The common use of antineoplastic agents such as mitomycin C, doxorubicin, or oxaliplatin with hyperthermia fails to eradicate tumors in a significant subset of patients, and alternative approaches to target chemoresistant cells are needed. The induction of reactive oxygen species (ROS) by inhibiting the critical detoxification enzyme superoxide dismutase (SOD) during hyperthermia is an appealing approach to induce death of residual cancer cells.Human and murine colon cancer cell lines were subjected to mild hyperthermia (40-42°C), and treated with chemotherapy, similar to clinical protocols. ROS were induced by the SOD inhibitor diethyldithiocarbamate (DDC), a metabolite of the drug disulfiram. In mice, peritoneal carcinomatosis use C57Bl/6 was induced in C57Bl/6 by intraperitoneal injection of syngenic tumor cells (MC38).Hyperthermia alone failed to kill cells but induced intracellular ROS and activated protective mechanisms. Chemotherapy conferred inconsistent cytotoxicity depending on the cell line and dose. In contrast, induction of ROS by DDC consistently activated apoptotic pathways, with increased cell death in combination with mild hyperthermia. In vivo, combined treatment with DDC and hyperthermia significantly delayed tumor progression in tumor-bearing mice. In addition, hyperthermic combined treatment with chemotherapy and DDC significantly improved animal survival compared with chemotherapy alone.Addition of DDC improves the efficacy of existing HIPEC protocols in a safe way and may open the door to a more effective, multimodal HIPEC.

    View details for DOI 10.1097/SLA.0b013e3182737517

    View details for PubMedID 23095616

  • gamma-Radiation Promotes Immunological Recognition of Cancer Cells through Increased Expression of Cancer-Testis Antigens In Vitro and In Vivo PLOS ONE Sharma, A., Bode, B., Wenger, R. H., Lehmann, K., Sartori, A. A., Moch, H., Knuth, A., von Boehmer, L., van den Broek, M. 2011; 6 (11): e28217

    Abstract

    γ-radiation is an effective treatment for cancer. There is evidence that radiotherapy supports tumor-specific immunity. It was described that irradiation induces de novo protein synthesis and enhances antigen presentation, we therefore investigated whether γ-radiation results in increased expression of cancer-testis (CT) antigens and MHC-I, thus allowing efficient immunological control. This is relevant because the expression of CT-antigens and MHC-I on tumor cells is often heterogeneous. We found that the changes induced by γ-radiation promote the immunological recognition of the tumor, which is illustrated by the increased infiltration by lymphocytes after radiotherapy.We compared the expression of CT-antigens and MHC-I in various cancer cell lines and fresh biopsies before and after in vitro irradiation (20 Gy). Furthermore, we compared paired biopsies that were taken before and after radiotherapy from sarcoma patients. To investigate whether the changed expression of CT-antigens and MHC-I is specific for γ-radiation or is part of a generalized stress response, we analyzed the effect of hypoxia, hyperthermia and genotoxic stress on the expression of CT-antigens and MHC-I. In vitro irradiation of cancer cell lines and of fresh tumor biopsies induced a higher or de novo expression of different CT-antigens and a higher expression of MHC-I in a time- and dose-dependent fashion. Importantly, we show that irradiation of cancer cells enhances their recognition by tumor-specific CD8+ T cells. The analysis of paired biopsies taken from a cohort of sarcoma patients before and after radiotherapy confirmed our findings and, in addition showed that irradiation resulted in higher infiltration by lymphocytes. Other forms of stress did not have an impact on the expression of CT-antigens or MHC-I.Our findings suggest that γ-radiation promotes the immunological recognition of the tumor. We therefore propose that combining radiotherapy with treatments that support tumor specific immunity may result in increased therapeutic efficacy.

    View details for DOI 10.1371/journal.pone.0028217

    View details for Web of Science ID 000298166300039

    View details for PubMedID 22140550

    View details for PubMedCentralID PMC3226680

  • MAGE-C2/CT10 protein expression is an independent predictor of recurrence in prostate cancer. PloS one von Boehmer, L., Keller, L., Mortezavi, A., Provenzano, M., Sais, G., Hermanns, T., Sulser, T., Jungbluth, A. A., Old, L. J., Kristiansen, G., van den Broek, M., Moch, H., Knuth, A., Wild, P. J. 2011; 6 (7): e21366

    Abstract

    The cancer-testis (CT) family of antigens is expressed in a variety of malignant neoplasms. In most cases, no CT antigen is found in normal tissues, except in testis, making them ideal targets for cancer immunotherapy. A comprehensive analysis of CT antigen expression has not yet been reported in prostate cancer. MAGE-C2/CT-10 is a novel CT antigen. The objective of this study was to analyze extent and prognostic significance of MAGE-C2/CT10 protein expression in prostate cancer. 348 prostate carcinomas from consecutive radical prostatectomies, 29 castration-refractory prostate cancer, 46 metastases, and 45 benign hyperplasias were immunohistochemically analyzed for MAGE-C2/CT10 expression using tissue microarrays. Nuclear MAGE-C2/CT10 expression was identified in only 3.3% primary prostate carcinomas. MAGE-C2/CT10 protein expression was significantly more frequent in metastatic (16.3% positivity) and castration-resistant prostate cancer (17% positivity; p<0.001). Nuclear MAGE-C2/CT10 expression was identified as predictor of biochemical recurrence after radical prostatectomy (p = 0.015), which was independent of preoperative PSA, Gleason score, tumor stage, and surgical margin status in multivariate analysis (p<0.05). MAGE-C2/CT10 expression in prostate cancer correlates with the degree of malignancy and indicates a higher risk for biochemical recurrence after radical prostatectomy. Further, the results suggest MAGE-C2/CT10 as a potential target for adjuvant and palliative immunotherapy in patients with prostate cancer.

    View details for DOI 10.1371/journal.pone.0021366

    View details for PubMedID 21754986

    View details for PubMedCentralID PMC3130772

  • Efficient in vivo priming by vaccination with recombinant NY-ESO-1 protein and CpG in antigen naive prostate cancer patients. Clinical cancer research : an official journal of the American Association for Cancer Research Karbach, J., Neumann, A., Atmaca, A., Wahle, C., Brand, K., von Boehmer, L., Knuth, A., Bender, A., Ritter, G., Old, L. J., Jäger, E. 2011; 17 (4): 861–70

    Abstract

    NY-ESO-1, one of the most immunogenic tumor antigens, is expressed in 15% to 25% of metastatic prostate cancers. The immunological and clinical effects of vaccination with recombinant NY-ESO-1 protein combined with CpG as adjuvant were evaluated.In a phase I clinical study, patients with advanced prostate cancer were vaccinated with recombinant NY-ESO-1 protein (100 μg) mixed with CpG 7909 (2.5 mg) every 3 weeks intradermally for 4 doses. Objectives of the study were the safety of the vaccine and changes of specific humoral and cellular immunological responses to NY-ESO-1 in relation to detectable NY-ESO-1 expression in the individual tumor.All 12 baseline sero-negative patients developed high-titer NY-ESO-1 antibody responses. B-cell epitope mapping identified NY-ESO-1 p91-110 to be recognized most frequently by vaccine-induced antibodies. Two patients developed significant antibody titers against the adjuvant CpG. NY-ESO-1-specific CD4+ and/or CD8+ T-cell responses were induced in 9 patients (69%). Five of these 9 patients did not express NY-ESO-1 in the autologous tumor. Postvaccine CD8+ T-cell clones recognized and lyzed HLA-matched tumor cell lines in an antigen-specific manner.Our data provide clear evidence for the capacity of NY-ESO-1 protein/CpG vaccine to induce integrated antigen-specific immune responses in vivo and to efficiently prime CD8+ T-cell responses in NY-ESO-1 antigen-negative patients. Our results may also support further clinical vaccination protocols with NY-ESO-1 protein not only focused on the treatment of existing cancer, but also to prevent further development of NY-ESO-1 positive cancers in vivo.

    View details for DOI 10.1158/1078-0432.CCR-10-1811

    View details for PubMedID 21163871

  • Quantitative computed tomography liver perfusion imaging using dynamic spiral scanning with variable pitch: feasibility and initial results in patients with cancer metastases. Investigative radiology Goetti, R., Leschka, S., Desbiolles, L., Klotz, E., Samaras, P., von Boehmer, L., Stenner, F., Reiner, C., Stolzmann, P., Scheffel, H., Knuth, A., Marincek, B., Alkadhi, H. 2010; 45 (7): 419–26

    Abstract

    To assess the feasibility and image quality of computed tomography (CT) liver perfusion imaging using an adaptive 4D spiral-mode, developed to extend the z-axis coverage, and to report initial qualitative and quantitative results in patients with cancer metastases.A total of 21 patients with liver metastases of various origins underwent CT perfusion imaging (100 kV and 150 mAs/rot) using a 4D spiral-mode with single-source 64-slice CT (n = 7) with a scan range of 6.7 cm (protocol A: 16 cycles, 46.5 seconds examination time), or dual-source 128-slice CT with a scan range of 14.8 cm (protocol B: 16 cycles, 46.5 seconds examination time, n = 7; protocol C: 12 cycles, 51.0 seconds examination time, n = 7). Ability to suspend respiration during perfusion imaging was monitored. Two independent readers assessed image quality on a 4-point scale, both before and after motion correction, and performed a qualitative (ie, arterial enhancement pattern and enhancement change over time) and quantitative perfusion (ie, arterial liver perfusion [ALP]; portal-venous perfusion [PVP]; hepatic perfusion index [HPI]) analysis.Of 21 patients, 7 (33%) could suspend respiration throughout the perfusion study and 14 (67%) resumed shallow breathing during the perfusion scan. The 21 patients had a total of 88 metastases. The scan range of protocol A covered at least 1 metastasis in all patients (total 20/34 [58.8%] metastases). The scan range of protocol B and C covered 53 of 54 (98.1%) metastases, whereas one metastasis in segment VIII was only partially imaged. Image quality was diagnostic both before and after motion correction, whereas being significantly better after motion correction (P < 0.001). Qualitative perfusion analysis of 67 metastases revealed diffuse arterial enhancement in 3 (4.5%), sparse enhancement in 11 (16.4%), peripheral-nodular enhancement in 9 (13.4%), rim-like enhancement in 15 (22.4%), and none in 29 (43.3%) metastases. Enhancement over time of 67 metastases showed a centripetal progression in 6 (8.9%), sustained portal phase in 16 (23.9%), wash-out in 16 (23.9%), and none in 29 (43.3%) metastases. Quantitative perfusion analysis revealed significantly higher arterial liver perfusion and HPI in metastases and metastasis borders than in adjacent normal liver tissue (P < 0.001 each). Portal-venous perfusion was significantly lower in metastases and metastasis borders than in normal liver tissue (P < 0.001). There were no significant differences in image quality and qualitative perfusion analysis between the 3 protocols (P = n.s.). Calculated effective radiation doses were 13.4 mSv for protocol A, 30.7 mSv for protocol B, and 23.0 mSv for protocol C.CT perfusion imaging of the liver using the 4D spiral-mode is feasible with diagnostic image quality, and enables the reliable qualitative and quantitative analysis of the normal and metastatic liver parenchyma. Radiation dose issues must be considered when determining the scan range, number of cycles, and scan duration of the perfusion CT protocol.

    View details for DOI 10.1097/RLI.0b013e3181e1937b

    View details for PubMedID 20498611

  • Developments in cancer immunotherapy. Digestive diseases (Basel, Switzerland) van den Broek, M., von Boehmer, L., Knuth, A. 2010; 28 (1): 51–56

    Abstract

    Significant advances have been made in the field of cancer immunology and immunotherapy over the last three decades. An important step forward was the identification of human cancer antigens eliciting spontaneous immune responses in cancer patients. The most immunogenic human cancer antigens known to date belong to the cancer-testis family of antigens, which are proteins expressed in various types of cancer but not in any healthy tissues except germ cells. The aim of cancer immunotherapy is to induce or boost the existing tumor-specific immune response by vaccinating with a relevant antigen together with an adjuvant. Immunization together with an adjuvant will induce a strong and effective immune response or can qualitatively and quantitatively improve existing responses. As selective outgrowth of antigen-loss variants due to immunoediting in vivo may occur during vaccination of cancer patients, singular metastatic failure sites of disease should be surgically removed and tested for antigen expression as antigen-negative (or loss) variants may have survived the pressure of the immune system. At this rather early stage of development, cancer immunotherapy should be offered to cancer patients only within carefully monitored clinical trials of experienced clinical research teams. In addition, it may be rewarding to include patients with early-stage disease in immunotherapy trials, as immunoediting of the tumor and immune escape may be less pronounced.

    View details for DOI 10.1159/000282064

    View details for PubMedID 20460890

  • Fine analysis of spontaneous MAGE-C1/CT7-specific immunity in melanoma patients. Proceedings of the National Academy of Sciences of the United States of America Nuber, N., Curioni-Fontecedro, A., Matter, C., Soldini, D., Tiercy, J. M., von Boehmer, L., Moch, H., Dummer, R., Knuth, A., van den Broek, M. 2010; 107 (34): 15187–92

    Abstract

    Cancer/testis (CT) antigens represent prime candidates for immunotherapy in cancer patients, because their expression is restricted to cancer cells and germ cells of the testis. MAGE-C1/CT7 is a CT antigen that is highly expressed in several types of cancers. Spontaneous occurrence of CT7-specific antibodies was previously detected by SEREX screen in a melanoma patient. However, naturally occurring CT7-specific T-cell responses have thus far not been detected. Peripheral blood mononuclear cells (PBMCs) from 26 metastatic melanoma patients expressing CT7 in their tumor lesions (CT7(+)) were analyzed for CT7-specific T-cell responses using overlapping peptides. CT7-specific CD4(+) T-cell responses were detected in three patients (11.5%). These CT7-specific CD4(+) T-cell responses were detectable in melanoma patients' PBMCs exclusively from preexisting CD45RA(-) memory CD4(+) T-cell pool. Additional CT7-specific memory CD4(+) T-cell responses were detected in CT7(+) melanoma patients after depletion of CD4(+)CD25high Treg cells showing that Treg cells impact on CT7-specific CD4(+) T cells in melanoma patients. CT7-specific CD4(+) T-cell clones were generated and used to define minimal epitopes, restriction elements, and confirm the recognition of naturally processed antigen. Surprisingly, these clones were able to secrete perforin and exert cytotoxicity. This study shows that CT7 can induce specific cellular immunity in melanoma patients. Based on these findings, CT7 will be further explored as a potential vaccine for melanoma immunotherapy.

    View details for DOI 10.1073/pnas.1002155107

    View details for PubMedID 20696919

    View details for PubMedCentralID PMC2930530

  • Particle size and activation threshold: a new dimension of danger signaling. Blood Rettig, L., Haen, S. P., Bittermann, A. G., von Boehmer, L., Curioni, A., Krämer, S. D., Knuth, A., Pascolo, S. 2010; 115 (22): 4533–41

    Abstract

    Previous studies have shown that single-stranded RNA (ssRNA) mixed with protamine forms particles and activates immune cells through Toll-like receptors (TLRs). We have found that the size of protamine-RNA particles generated depends on the electrolyte content when mixing the 2 components. Moreover, we have evidenced that (1) nanometric particles induce production of interferon-alpha, whereas (2) micrometric particles mainly induce production of tumor necrosis factor-alpha (TNF-alpha) in human immune cells. We found that the mechanisms underlying these observations are (1) nanoparticles but not microparticles are selectively phagocytosed by plasmacytoid dendritic cells (pDCs), which produce interferon-alpha and (2) monocytes that produce TNF-alpha have a higher activation threshold than that of pDCs. Thus, at the same time as sensing pathogen-associated molecular patterns such as ssRNA, the immune system distinguishes the size of the associated structure in such a way as to trigger the adapted antivirus (nanometric) or antibacterial/antifungal (micrometric) immune response. Our results introduce a new dimension in danger signaling--how size qualitatively affects innate response.

    View details for DOI 10.1182/blood-2009-11-247817

    View details for PubMedID 20304804

  • MAGE-C1/CT7 is the dominant cancer-testis antigen targeted by humoral immune responses in patients with multiple myeloma. Leukemia Curioni-Fontecedro, A., Knights, A. J., Tinguely, M., Nuber, N., Schneider, C., Thomson, C. W., von Boehmer, L., Bossart, W., Pahlich, S., Gehring, H., Moch, H., Renner, C., Knuth, A., Zippelius, A. 2008; 22 (8): 1646–48

    View details for DOI 10.1038/leu.2008.43

    View details for PubMedID 18323799

  • Germinal center B cells are dispensable in prion transport and neuroinvasion. Journal of neuroimmunology Heikenwalder, M., Federau, C., Boehmer, L. v., Schwarz, P., Wagner, M., Zeller, N., Haybaeck, J., Prinz, M., Becher, B., Aguzzi, A. 2007; 192 (1-2): 113–23

    Abstract

    Transmissible spongiform encephalopathies (TSEs) are fatal neurodegenerative diseases of animals and humans. Many TSEs are initiated by prion replication in the lymphoreticular system (LRS). The cellular and molecular prerequisites for prion trafficking within the LRS are not fully understood. Here we have manipulated CD40 and its ligand to investigate whether genetic or pharmacological ablation of germinal center B cells (GCBs), which migrate into and out of germinal centers, influences prion pathogenesis. In contrast to previous reports, no alteration of prion pathogenesis was detected in mice lacking CD40L and in mice treated with anti-CD40L antibodies. These results suggest that GCBs alone do not impact peripheral splenic prion transport, replication efficiency, or neuroinvasion, and point to other mechanisms affecting prion transport from lymphoreticular sites of replication to the nervous system.

    View details for DOI 10.1016/j.jneuroim.2007.09.022

    View details for PubMedID 17964667

  • Images in cardiovascular medicine. Infarction-like electrocardiographic changes due to a myocardial metastasis from a primary lung cancer. Circulation Samaras, P., Stenner-Liewen, F., Bauer, S., Goerres, G. W., von Boehmer, L., Kotrubczik, N., Jenni, R., Renner, C., Knuth, A. 2007; 115 (10): e320–1

    View details for DOI 10.1161/CIRCULATIONAHA.106.650762

    View details for PubMedID 17353451

  • Alteration of GABAergic synapses and gephyrin clusters in the thalamic reticular nucleus of GABAA receptor alpha3 subunit-null mice. The European journal of neuroscience Studer, R., von Boehmer, L., Haenggi, T., Schweizer, C., Benke, D., Rudolph, U., Fritschy, J. M. 2006; 24 (5): 1307–15

    Abstract

    Multiple GABAA-receptor subtypes are assembled from alpha, beta and gamma subunit variants. GABAA receptors containing the alpha3 subunit represent a minor population with a restricted distribution in the CNS. In addition, they predominate in monoaminergic neurons and in the nucleus reticularis thalami (nRT), suggesting a role in the regulation of cortical function and sleep. Mice with a targeted deletion of the alpha3 subunit gene (alpha3(0/0)) are viable and exhibit a subtle behavioural phenotype possibly related to dopaminergic hyperfunction. Here, we investigated immunohistochemically the consequences of the loss of alpha3 subunit for maturation of GABAA receptors and formation of GABAergic synapses in the nRT. Throughout postnatal development, the regional distribution of the alpha1, alpha2, or alpha5 subunit was unaltered in alpha3(0/0) mice and the prominent alpha3 subunit staining of nRT neurons in wildtype mice was not replaced. Subcellularly, as seen by double immunofluorescence, the alpha3 and gamma2 subunit were clustered at postsynaptic sites in the nRT of adult wildtype mice along with the scaffolding protein gephyrin. In alpha3(0/0) mice, gamma2 subunit clustering was disrupted and gephyrin formed large aggregates localized at the cell surface, but unrelated to postsynaptic sites, indicating that nRT neurons lack postsynaptic GABAA receptors in mutant mice. Furthermore, GABAergic terminals were enlarged and reduced in number, suggesting a partial deficit of GABAergic synapses. Therefore, GABAA receptors are required for gephyrin clustering and long-term synapse maintenance. The absence of GABAA-mediated transmission in the nRT may have a significant impact on the function of the thalamo-cortical loop of alpha3(0/0) mice.

    View details for DOI 10.1111/j.1460-9568.2006.05006.x

    View details for PubMedID 16987218

  • A schizophrenia-related sensorimotor deficit links alpha 3-containing GABA(A) receptors to a dopamine hyperfunction PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Yee, B. K., Keist, R., von Boehmer, L., Studer, R., Benke, D., Hagenbuch, N., Dong, Y., Malenka, R. C., Fritschy, J. M., Bluethmann, H., Feldon, J., Mohler, H., Rudolph, U. 2005; 102 (47): 17154-17159

    Abstract

    Overactivity of the dopaminergic system in the brain is considered to be a contributing factor to the development and symptomatology of schizophrenia. Therefore, the GABAergic control of dopamine functions was assessed by disrupting the gene encoding the alpha3 subunit of the GABA(A) receptor. alpha3 knockout (alpha3KO) mice exhibited neither an obvious developmental defect nor apparent morphological brain abnormalities, and there was no evidence for compensatory up-regulation of other major GABA(A)-receptor subunits. Anxiety-related behavior in the elevated-plus-maze test was undisturbed, and the anxiolytic-like effect of diazepam, which is mediated by alpha2-containing GABA(A) receptors, was preserved. As a result of the loss of alpha3 GABA(A) receptors, the GABA-induced whole-cell current recorded from midbrain dopamine neurons was significantly reduced. Spontaneous locomotor activity was slightly elevated in alpha3KO mice. Most notably, prepulse inhibition of the acoustic startle reflex was markedly attenuated in the alpha3KO mice, pointing to a deficit in sensorimotor information processing. This deficit was completely normalized by treatment with the antipsychotic D2-receptor antagonist haloperidol. The amphetamine-induced hyperlocomotion was not altered in alpha3KO mice compared with WT mice. These results suggest that the absence of alpha3-subunit-containing GABA(A) receptors induces a hyperdopaminergic phenotype, including a severe deficit in sensorimotor gating, a common feature among psychiatric conditions, including schizophrenia. Hence, agonists acting at alpha3-containing GABA(A) receptors may constitute an avenue for an effective treatment of sensorimotor-gating deficits in various psychiatric conditions.

    View details for DOI 10.1073/pnas.0508752102

    View details for Web of Science ID 000233463200045

    View details for PubMedID 16284244

    View details for PubMedCentralID PMC1288020