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Witney MJ, Tscharke DC. BMX-A and BMX-S: Accessible cell-free methods to estimate peptide-MHC-I affinity and stability. Mol Immunol 2023; 161:1-10. [PMID: 37478775 DOI: 10.1016/j.molimm.2023.07.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 06/12/2023] [Accepted: 07/11/2023] [Indexed: 07/23/2023]
Abstract
The affinity and stability of peptide binding to Major Histocompatibility Complex Class I (MHC-I) molecules are fundamental parameters that underpin the specificity and magnitude of CD8+ T cell responses. These parameters can be estimated in some cases by computational tools, but experimental validation remains valuable, especially for stability. Methods to measure peptide binding can be broadly categorised into either cell-based assays using TAP-deficient cell lines such as RMA/S, or cell-free strategies, such as peptide competition-binding assays and surface plasmon resonance. Cell-based assays are subject to confounding biological activity, including peptide trimming by peptidases and dilution of peptide-loaded MHC-I on the surface of cells through cell division. Current cell-free methods require in-house production and purification of MHC-I. In this study, we present the development of new cell-free assays to estimate the relative affinity and dissociation kinetics of peptide binding to MHC-I. These assays, which we have called BMX-A (relative affinity) and BMX-S (kinetic stability), are reliable, scalable and accessible, in that they use off-the-shelf commercial reagents and standard flow cytometry techniques.
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Affiliation(s)
- Matthew J Witney
- John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia
| | - David C Tscharke
- John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia.
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2
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Smyth M, Khamina K, Popa A, Gudipati V, Agerer B, Lercher A, Kosack L, Endler L, Baazim H, Viczenczova C, Huppa JB, Bergthaler A. Characterization of CD8 T Cell-Mediated Mutations in the Immunodominant Epitope GP33-41 of Lymphocytic Choriomeningitis Virus. Front Immunol 2021; 12:638485. [PMID: 34194424 PMCID: PMC8236698 DOI: 10.3389/fimmu.2021.638485] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Accepted: 05/25/2021] [Indexed: 11/13/2022] Open
Abstract
Cytotoxic T lymphocytes (CTLs) represent key immune effectors of the host response against chronic viruses, due to their cytotoxic response to virus-infected cells. In response to this selection pressure, viruses may accumulate escape mutations that evade CTL-mediated control. To study the emergence of CTL escape mutations, we employed the murine chronic infection model of lymphocytic choriomeningitis virus (LCMV). We developed an amplicon-based next-generation sequencing pipeline to detect low frequency mutations in the viral genome and identified non-synonymous mutations in the immunodominant LCMV CTL epitope, GP33-41, in infected wildtype mice. Infected Rag2-deficient mice lacking CTLs did not contain such viral mutations. By using transgenic mice with T cell receptors specific to GP33-41, we characterized the emergence of viral mutations in this epitope under varying selection pressure. We investigated the two most abundant viral mutations by employing reverse genetically engineered viral mutants encoding the respective mutations. These experiments provided evidence that these mutations prevent activation and expansion of epitope-specific CD8 T cells. Our findings on the mutational dynamics of CTL escape mutations in a widely-studied viral infection model contributes to our understanding of how chronic viruses interact with their host and evade the immune response. This may guide the development of future treatments and vaccines against chronic infections.
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Affiliation(s)
- Mark Smyth
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Kseniya Khamina
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Alexandra Popa
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Venugopal Gudipati
- Center for Pathophysiology, Infectiology and Immunology, Institute for Hygiene and Applied Immunology, Medical University of Vienna, Vienna, Austria
| | - Benedikt Agerer
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Alexander Lercher
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Lindsay Kosack
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Lukas Endler
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Hatoon Baazim
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Csilla Viczenczova
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Johannes B Huppa
- Center for Pathophysiology, Infectiology and Immunology, Institute for Hygiene and Applied Immunology, Medical University of Vienna, Vienna, Austria
| | - Andreas Bergthaler
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
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3
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Gilfillan CB, Hebeisen M, Rufer N, Speiser DE. Constant regulation for stable CD8 T-cell functional avidity and its possible implications for cancer immunotherapy. Eur J Immunol 2021; 51:1348-1360. [PMID: 33704770 PMCID: PMC8252569 DOI: 10.1002/eji.202049016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 12/16/2020] [Accepted: 03/05/2021] [Indexed: 12/30/2022]
Abstract
The functional avidity (FA) of cytotoxic CD8 T cells impacts strongly on their functional capabilities and correlates with protection from infection and cancer. FA depends on TCR affinity, downstream signaling strength, and TCR affinity-independent parameters of the immune synapse, such as costimulatory and inhibitory receptors. The functional impact of coreceptors on FA remains to be fully elucidated. Despite its importance, FA is infrequently assessed and incompletely understood. There is currently no consensus as to whether FA can be enhanced by optimized vaccine dose or boosting schedule. Recent findings suggest that FA is remarkably stable in vivo, possibly due to continued signaling modulation of critical receptors in the immune synapse. In this review, we provide an overview of the current knowledge and hypothesize that in vivo, codominant T cells constantly "equalize" their FA for similar function. We present a new model of constant FA regulation, and discuss practical implications for T-cell-based cancer immunotherapy.
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Affiliation(s)
- Connie B Gilfillan
- Department of Oncology, University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Michael Hebeisen
- Department of Oncology, University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Nathalie Rufer
- Department of Oncology, University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Daniel E Speiser
- Department of Oncology, University Hospital and University of Lausanne, Lausanne, Switzerland
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Shwetank, Frost EL, Mockus TE, Ren HM, Toprak M, Lauver MD, Netherby-Winslow CS, Jin G, Cosby JM, Evavold BD, Lukacher AE. PD-1 Dynamically Regulates Inflammation and Development of Brain-Resident Memory CD8 T Cells During Persistent Viral Encephalitis. Front Immunol 2019; 10:783. [PMID: 31105690 PMCID: PMC6499176 DOI: 10.3389/fimmu.2019.00783] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 03/25/2019] [Indexed: 01/07/2023] Open
Abstract
Programmed cell death-1 (PD-1) receptor signaling dampens the functionality of T cells faced with repetitive antigenic stimulation from chronic infections or tumors. Using intracerebral (i.c.) inoculation with mouse polyomavirus (MuPyV), we have shown that CD8 T cells establish a PD-1hi, tissue-resident memory population in the brains (bTRM) of mice with a low-level persistent infection. In MuPyV encephalitis, PD-L1 was expressed on infiltrating myeloid cells, microglia and astrocytes, but not on oligodendrocytes. Engagement of PD-1 on anti-MuPyV CD8 T cells limited their effector activity. NanoString gene expression analysis showed that neuroinflammation was higher in PD-L1-/- than wild type mice at day 8 post-infection, the peak of the MuPyV-specific CD8 response. During the persistent phase of infection, however, the absence of PD-1 signaling was found to be associated with a lower inflammatory response than in wild type mice. Genetic disruption and intracerebroventricular blockade of PD-1 signaling resulted in an increase in number of MuPyV-specific CD8 bTRM and the fraction of these cells expressing CD103, the αE integrin commonly used to define tissue-resident T cells. However, PD-L1-/- mice persistently infected with MuPyV showed impaired virus control upon i.c. re-infection with MuPyV. Collectively, these data reveal a temporal duality in PD-1-mediated regulation of MuPyV-associated neuroinflammation. PD-1 signaling limited the severity of neuroinflammation during acute infection but sustained a level of inflammation during persistent infection for maintaining control of virus re-infection.
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Affiliation(s)
- Shwetank
- Department of Microbiology and Immunology, Penn State College of Medicine, Hershey, PA, United States
| | - Elizabeth L. Frost
- Immunology and Molecular Pathogenesis Graduate Program, Emory University, Atlanta, GA, United States
| | - Taryn E. Mockus
- Department of Microbiology and Immunology, Penn State College of Medicine, Hershey, PA, United States
| | - Heather M. Ren
- Department of Microbiology and Immunology, Penn State College of Medicine, Hershey, PA, United States
| | - Mesut Toprak
- Section of Neuropathology, Yale School of Medicine, New Haven, CT, United States
| | - Matthew D. Lauver
- Department of Microbiology and Immunology, Penn State College of Medicine, Hershey, PA, United States
| | | | - Ge Jin
- Department of Microbiology and Immunology, Penn State College of Medicine, Hershey, PA, United States
| | - Jennifer M. Cosby
- Department of Pathology, Microbiology and Immunology, University of Utah, Salt Lake City, UT, United States
| | - Brian D. Evavold
- Department of Pathology, Microbiology and Immunology, University of Utah, Salt Lake City, UT, United States
| | - Aron E. Lukacher
- Department of Microbiology and Immunology, Penn State College of Medicine, Hershey, PA, United States,*Correspondence: Aron E. Lukacher
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Sant AJ, DiPiazza AT, Nayak JL, Rattan A, Richards KA. CD4 T cells in protection from influenza virus: Viral antigen specificity and functional potential. Immunol Rev 2019; 284:91-105. [PMID: 29944766 DOI: 10.1111/imr.12662] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
CD4 T cells convey a number of discrete functions to protective immunity to influenza, a complexity that distinguishes this arm of adaptive immunity from B cells and CD8 T cells. Although the most well recognized function of CD4 T cells is provision of help for antibody production, CD4 T cells are important in many aspects of protective immunity. Our studies have revealed that viral antigen specificity is a key determinant of CD4 T cell function, as illustrated both by mouse models of infection and human vaccine responses, a factor whose importance is due at least in part to events in viral antigen handling. We discuss research that has provided insight into the diverse viral epitope specificity of CD4 T cells elicited after infection, how this primary response is modified as CD4 T cells home to the lung, establish memory, and after challenge with a secondary and distinct influenza virus strain. Our studies in human subjects point out the challenges facing vaccine efforts to facilitate responses to novel and avian strains of influenza, as well as strategies that enhance the ability of CD4 T cells to promote protective antibody responses to both seasonal and potentially pandemic strains of influenza.
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Affiliation(s)
- Andrea J Sant
- David H. Smith Center for Vaccine Biology and Immunology, Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY, USA
| | - Anthony T DiPiazza
- David H. Smith Center for Vaccine Biology and Immunology, Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY, USA
| | - Jennifer L Nayak
- David H. Smith Center for Vaccine Biology and Immunology, Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY, USA.,Division of Infectious Diseases, Department of Pediatrics, University of Rochester Medical Center, Rochester, NY, USA
| | - Ajitanuj Rattan
- David H. Smith Center for Vaccine Biology and Immunology, Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY, USA
| | - Katherine A Richards
- David H. Smith Center for Vaccine Biology and Immunology, Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY, USA
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Kolawole EM, Andargachew R, Liu B, Jacobs JR, Evavold BD. 2D Kinetic Analysis of TCR and CD8 Coreceptor for LCMV GP33 Epitopes. Front Immunol 2018; 9:2348. [PMID: 30374353 PMCID: PMC6197077 DOI: 10.3389/fimmu.2018.02348] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 09/21/2018] [Indexed: 11/13/2022] Open
Abstract
The LCMV GP33 CD8 epitope has long been one of the most widely used antigens in viral immunology. Of note, almost all of the in vitro analyses of CD8 T cell responses to this epitope make use of an altered peptide ligand (APL) in which the cysteine from the original 9-mer peptide (KAVYNFATC) is substituted by a methionine at position 41 (KAVYNFATM). In addition, it is possible that the antigen processed during natural LCMV infection is an 11-mer peptide (KAVYNFATCGI) rather than the widely used 9-mer. Although previous affinity measurements using purified proteins for these antigen variants revealed minimal differences, we applied highly sensitive two dimensional (2D) biophysical based techniques to further dissect TCR interaction with these closely related GP33 variants. The kinetic analyses of affinity provided by the 2D micropipette adhesion frequency assay (2D-MP) and bond lifetime under force analyzed using a biomembrane force probe (BFP) revealed significant differences between 41M, 41C and the 11-mer 41CGI antigen. We found a hierarchy in 2D affinity as 41M peptide displayed augmented TCR 2D affinity compared to 41C and 41CGI. These differences were also maintained in the presence of CD8 coreceptor and when analysis of total TCR:pMHC and CD8:pMHC bonds were considered. Moreover, the three ligands displayed dramatic differences in the bond lifetimes generated under force, in particular the 41CGI variant with the lowest 2D affinity demonstrated a 15-fold synergistic contribution of the CD8 coreceptor to overall bond lifetime. Our analyses emphasize the sensitivity of single cell and single bond 2D kinetic measurements in distinguishing between related agonist peptides.
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Affiliation(s)
- Elizabeth M Kolawole
- Department of Pathology, Microbiology and Immunology, University of Utah, Salt Lake City, UT, United States
| | - Rakieb Andargachew
- Department of Microbiology and Immunology, Emory University, Atlanta, GA, United States
| | - Baoyu Liu
- Department of Pathology, Microbiology and Immunology, University of Utah, Salt Lake City, UT, United States
| | - Jesica R Jacobs
- Department of Pathology, Microbiology and Immunology, University of Utah, Salt Lake City, UT, United States
| | - Brian D Evavold
- Department of Pathology, Microbiology and Immunology, University of Utah, Salt Lake City, UT, United States
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Andargachew R, Martinez RJ, Kolawole EM, Evavold BD. CD4 T Cell Affinity Diversity Is Equally Maintained during Acute and Chronic Infection. THE JOURNAL OF IMMUNOLOGY 2018; 201:19-30. [PMID: 29777029 DOI: 10.4049/jimmunol.1800295] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 04/30/2018] [Indexed: 12/31/2022]
Abstract
TCR affinity for peptide MHC dictates the functional efficiency of T cells and their propensity to differentiate into effectors and form memory. However, in the context of chronic infections, it is unclear what the overall profile of TCR affinity for Ag is and if it differs from acute infections. Using the comprehensive affinity analysis provided by the two-dimensional micropipette adhesion frequency assay and the common indirect affinity evaluation methods of MHC class II tetramer and functional avidity, we tracked IAb GP61-80-specific cells in the mouse model of acute (Armstrong) and chronic (clone 13) lymphocytic choriomeningitis virus infection. In each response, we show CD4 T cell population affinity peaks at the effector phase and declines with memory. Of interest, the range and average relative two-dimensional affinity was equivalent between acute and chronic infection, indicating chronic Ag exposure did not skew TCR affinity. In contrast, functional and tetramer avidity measurements revealed divergent results and lacked a consistent correlation with TCR affinity. Our findings highlight that the immune system maintains a diverse range in TCR affinity even under the pressures of chronic Ag stimulation.
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Affiliation(s)
- Rakieb Andargachew
- Department of Microbiology and Immunology, Emory University, Atlanta, GA 30322
| | - Ryan J Martinez
- School of Medicine, Emory University, Atlanta, GA 30322; and
| | - Elizabeth M Kolawole
- Division of Microbiology and Immunology, Department of Pathology, University of Utah, Salt Lake City, UT 84112
| | - Brian D Evavold
- Division of Microbiology and Immunology, Department of Pathology, University of Utah, Salt Lake City, UT 84112
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8
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T cell immunity to Zika virus targets immunodominant epitopes that show cross-reactivity with other Flaviviruses. Sci Rep 2018; 8:672. [PMID: 29330423 PMCID: PMC5766511 DOI: 10.1038/s41598-017-18781-1] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 12/18/2017] [Indexed: 11/09/2022] Open
Abstract
Zika virus (ZIKV) Infection has several outcomes from asymptomatic exposure to rash, conjunctivitis, Guillain-Barré syndrome or congenital Zika syndrome. Analysis of ZIKV immunity is confounded by the fact that several related Flaviviruses infect humans, including Dengue virus 1-4, West Nile virus and Yellow Fever virus. HLA class II restricted T cell cross-reactivity between ZIKV and other Flaviviruses infection(s) or vaccination may contribute to protection or to enhanced immunopathology. We mapped immunodominant, HLA class II restricted, CD4 epitopes from ZIKV Envelope (Env), and Non-structural (NS) NS1, NS3 and NS5 antigens in HLA class II transgenic mice. In several cases, ZIKV primed CD4 cells responded to homologous sequences from other viruses, including DENV1-4, WNV or YFV. However, cross-reactive responses could confer immune deviation - the response to the Env DENV4 p1 epitope in HLA-DR1 resulted in IL-17A immunity, often associated with exacerbated immunopathogenesis. This conservation of recognition across Flaviviruses, may encompass protective and/or pathogenic components and poses challenges to characterization of ZIKV protective immunity.
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Maru S, Jin G, Schell TD, Lukacher AE. TCR stimulation strength is inversely associated with establishment of functional brain-resident memory CD8 T cells during persistent viral infection. PLoS Pathog 2017; 13:e1006318. [PMID: 28410427 PMCID: PMC5406018 DOI: 10.1371/journal.ppat.1006318] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 04/26/2017] [Accepted: 03/27/2017] [Indexed: 11/22/2022] Open
Abstract
Establishing functional tissue-resident memory (TRM) cells at sites of infection is a newfound objective of T cell vaccine design. To directly assess the impact of antigen stimulation strength on memory CD8 T cell formation and function during a persistent viral infection, we created a library of mouse polyomavirus (MuPyV) variants with substitutions in a subdominant CD8 T cell epitope that exhibit a broad range of efficiency in stimulating TCR transgenic CD8 T cells. By altering a subdominant epitope in a nonstructural viral protein and monitoring memory differentiation of donor monoclonal CD8 T cells in immunocompetent mice, we circumvented potentially confounding changes in viral infection levels, virus-associated inflammation, size of the immunodominant virus-specific CD8 T cell response, and shifts in TCR affinity that may accompany temporal recruitment of endogenous polyclonal cells. Using this strategy, we found that antigen stimulation strength was inversely associated with the function of memory CD8 T cells during a persistent viral infection. We further show that CD8 TRM cells recruited to the brain following systemic infection with viruses expressing epitopes with suboptimal stimulation strength respond more efficiently to challenge CNS infection with virus expressing cognate antigen. These data demonstrate that the strength of antigenic stimulation during recruitment of CD8 T cells influences the functional integrity of TRM cells in a persistent viral infection. Tissue-resident memory (TRM) cells are a subset of memory T cells that primarily reside in non-lymphoid tissues and serve as sentinels and effectors against secondary infections. TRM cells have been extensively characterized in mucosal barriers, but much less is known about this population in non-barrier sites such as the brain. In this study, we designed a novel strategy to evaluate the impact of T cell stimulation strength on the generation and functionality of memory CD8 T cells in both lymphoid and nonlymphoid tissues. Using a mouse polyomavirus (MuPyV) library expressing variants of a subdominant epitope recognized by TCR transgenic CD8 T cells, we found that systemic infection producing weaker responses during T cell priming was sufficient for recruitment of effector cells to the brain. Furthermore, lower stimulation conferred greater functionality to memory T cells in the spleen and to brain TRM cells. Our findings demonstrate that the strength of antigenic stimulation experienced by a naïve T cell early in infection is a determinant of memory functional integrity during viral persistence in a non-barrier organ.
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Affiliation(s)
- Saumya Maru
- Department of Microbiology and Immunology, Penn State College of Medicine, Hershey, Pennsylvania, United States of America
| | - Ge Jin
- Department of Microbiology and Immunology, Penn State College of Medicine, Hershey, Pennsylvania, United States of America
| | - Todd D. Schell
- Department of Microbiology and Immunology, Penn State College of Medicine, Hershey, Pennsylvania, United States of America
| | - Aron E. Lukacher
- Department of Microbiology and Immunology, Penn State College of Medicine, Hershey, Pennsylvania, United States of America
- * E-mail:
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