Honors & Awards
Distinguished Military Graduate, Department of the Army (June 2017)
Highest Departmental Honors, Department of Chemistry and Biochemistry, UCLA (June 2017)
Dean’s Prize Science Award for Excellence in Research, UCLA URC-Sciences (May 2017)
Professional Affiliations and Activities
Member, Infectious Diseases Society of America (2019 - Present)
Member, American Society for Investigative Pathology (2018 - Present)
IDIG: Infectious Diseases Interest Group, Co-Founder
Direct comparison of antibody responses to four SARS-CoV-2 vaccines in Mongolia.
Cell host & microbe
Different SARS-CoV-2 vaccines are approved in various countries, but few direct comparisons of the antibody responses they stimulate have been reported. We collected plasma specimens in July 2021 from 196 Mongolian participants fully vaccinated with one of four COVID-19 vaccines: Pfizer/BioNTech, AstraZeneca, Sputnik V, and Sinopharm. Functional antibody testing with a panel of nine SARS-CoV-2 viral variant receptor binding domain (RBD) proteins revealed marked differences in vaccine responses, with low antibody levels and RBD-ACE2 blocking activity stimulated by the Sinopharm and Sputnik V vaccines in comparison to the AstraZeneca or Pfizer/BioNTech vaccines. The Alpha variant caused 97% of infections in Mongolia in June and early July 2021. Individuals who recover from SARS-CoV-2 infection after vaccination achieve high antibody titers in most cases. These data suggest that public health interventions such as vaccine boosting, potentially with more potent vaccine types, may be needed to control COVID-19 in Mongolia and worldwide.
View details for DOI 10.1016/j.chom.2021.11.004
View details for PubMedID 34861167
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
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
Proinflammatory IgG Fc structures in patients with severe COVID-19
View details for DOI 10.1038/s41590-020-00828-7
Symptomatic SARS-CoV-2 infections display specific IgG Fc structures.
medRxiv : the preprint server for health sciences
The ongoing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has caused a public health crisis that is exacerbated by our poor understanding of correlates of immunity. SARS-CoV-2 infection can cause Coronavirus Disease 2019 (COVID-19), with a spectrum of symptoms ranging from asymptomatic carriage to life threatening pneumonia and cytokine dysregulation [1-3]. Although antibodies have been shown in a variety of in vitro assays to promote coronavirus infections through mechanisms requiring interactions between IgG antibodies and Fc gamma receptors (FcγRs), the relevance of these observations to coronavirus infections in humans is not known [4-7]. In light of ongoing clinical trials examining convalescent serum therapy for COVID-19 patients and expedited SARS-CoV-2 vaccine testing in humans, it is essential to clarify the role of antibodies in the pathogenesis of COVID-19. Here we show that adults with PCR-diagnosed COVID-19 produce IgG antibodies with a specific Fc domain repertoire that is characterized by reduced fucosylation, a modification that enhances interactions with the activating FcγR, FcγRIIIa. Fc fucosylation was reduced when compared with SARS-CoV-2-seropositive children and relative to adults with symptomatic influenza virus infections. These results demonstrate an antibody correlate of symptomatic SARS-CoV-2 infections in adults and have implications for novel therapeutic strategies targeting FcγRIIIa pathways.
View details for DOI 10.1101/2020.05.15.20103341
View details for PubMedID 32511463
View details for PubMedCentralID PMC7252581
HSP70 Copurifies with Zika Virus Particles
2018; 522: 228–33
Zika virus (ZIKV) has been identified as a cause of neurologic diseases in infants and Guillain-Barré Syndrome, and currently, no therapeutics or vaccines are approved. In this study, we sought to identify potential host proteins interacting with ZIKV particles to gain better insights into viral infectivity. Viral particles were purified through density-gradient centrifugation and subsequently, size-exclusion chromatography (SEC). Mass spectrometric analyses revealed viral envelope protein and HSP70 to comigrate in only one SEC fraction. Neither of these proteins were found in any other SEC fractions. We then performed neutralization assays and found that incubating viral particles with antibody against HSP70 indeed significantly reduced viral infectivity, while HSC70 antibody did not. Preincubating cells with recombinant HSP70 also decreased viral infectivity. Knockdown and inhibition of HSP70 also significantly diminished viral production. These results implicate HSP70 in the pathogenesis of ZIKV and identify HSP70 as a potential host therapeutic target against ZIKV infection.
View details for DOI 10.1016/j.virol.2018.07.009
View details for Web of Science ID 000442062700024
View details for PubMedID 30053656
Prediction of Histologic Alcoholic Hepatitis Based on Clinical Presentation Limits the Need for Liver Biopsy
2017; 1 (10): 1070–84
The clinical presentation of alcoholic hepatitis (AH) can be mimicked by other alcoholic liver diseases. The aim of this study was to identify clinical features that predict AH on liver biopsy. Biopsies from patients hospitalized for presumed severe AH were used to identify a derivation cohort (101 patients) and validation cohort (71 patients). Using histologic scores for hepatocyte ballooning, Mallory-Denk bodies, and lobular inflammation, 95 patient biopsies (55%) were classified as definite AH, 55 (32%) as possible AH, and 22 (13%) as no AH. Survival was similar among the groups, but mortality was significantly increased for patients with fatty change ≤50% on initial liver biopsy. An analysis limited to uninfected patients with definite AH or no AH in the derivation cohort identified a greater leukocyte count at admission and radiographic evidence of liver surface nodularity as independent predictors of definite AH on biopsy (P < 0.05). In the derivation cohort, the leukocyte count thresholds for ensuring 100% specificity for diagnosing definite AH were 10 × 109/L if the liver surface was nodular and 14 × 109/L if the liver surface was smooth, with a sensitivity of 76% and an area under the receiver operator characteristic curve of 0.88. In the validation cohort, these thresholds had a specificity of 86%, a sensitivity of 59%, and an area under the receiver operator characteristic curve of 0.72. Conclusion: The combination of an elevated leukocyte count and a nodular liver surface in the absence of active infection retrospectively identified patients with a high likelihood of histologic AH for whom liver biopsy may not be necessary. For patients with suspected severe AH who do not fulfill these criteria, liver biopsy is important to exclude other variants of alcoholic liver disease. (Hepatology Communications 2017;1:1070-1084).
View details for DOI 10.1002/hep4.1119
View details for Web of Science ID 000453177500008
View details for PubMedID 29404443
View details for PubMedCentralID PMC5721404
Digital quantitation of HCC-associated stem cell markers and protein quality control factors using tissue arrays of human liver sections
EXPERIMENTAL AND MOLECULAR PATHOLOGY
2014; 97 (3): 399–410
The most common type of liver cancer, hepatocellular carcinoma (HCC), affects over 500,000 people in the world. In the present study, liver tumor resections were used to prepare tissue arrays to examine the intensity of fluorescence of IHC stained stem cell markers in liver tissue from malignant HCC tumors and accompanying surrounding non-tumor liver. We hypothesized that a correlation exists between the fluorescence intensity of IHC stained HCC and surrounding non-tumor liver compared to liver tissue from a completely normal liver. 120 liver resection specimens (including four normal controls) were placed on a single slide to make a tissue array. They were examined by digitally quantifying the intensity of fluorescence using immuno-histochemically stained stem cell markers and protein quality control proteins. The stem cell markers were OCT3/4, Nanog, CD133, pEZH2, CD49F and SOX2. The protein quality control proteins were FAT10, UBA-6 and ubiquitin. The data collected was used to compare normal liver tissue with HCCs and parent liver tissue resected surgically using antibodies to stem cell markers and quality control protein markers. The measurements of the stem cell marker CD133 indicated an increase of fluorescence intensity for both the parent liver tissue and the HCC liver tissues. The other stem cell markers changed as follows: Nanog and OCT3/4 were decreased in both the HCCs and the parent livers; PEZH2 was reduced in the HCCs; SOX2 was increased in the parent livers compared to the controls; and CD49f was decreased in HCCs only. Protein quality control markers FAT10 and ubiquitin were downregulated in both the HCCs and the adjacent non-tumor tissue compared to the controls. UBA6 was increased in both the HCCs and the parent livers, and the levels were higher in the HCCs compared to the parent livers.
View details for DOI 10.1016/j.yexmp.2014.09.002
View details for Web of Science ID 000346685700012
View details for PubMedID 25218810
View details for PubMedCentralID PMC4262606