1
|
Li W, Chaihu L, Jiang J, Wu B, Zheng X, Dai R, Tian Y, Huang Y, Wang G, Men Y. Microfluidic Platform for Time-Resolved Characterization of Protein Higher-Order Structures and Dynamics Using Top-Down Mass Spectrometry. Anal Chem 2022; 94:7520-7527. [PMID: 35584038 DOI: 10.1021/acs.analchem.2c00077] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Characterization of protein higher-order structures and dynamics is essential for understanding the biological functions of proteins and revealing the underlying mechanisms. Top-down mass spectrometry (MS) accesses structural information at both the intact protein level and the peptide fragment level. Native top-down MS allows analysis of a protein complex's architecture and subunits' identity and modifications. Top-down hydrogen/deuterium exchange (HDX) MS offers high spatial resolution for conformational or binding interface analysis and enables conformer-specific characterization. A microfluidic chip can provide superior performance for front-end reactions useful for these MS workflows, such as flexibility in manipulating multiple reactant flows, integrating various functional modules, and automation. However, most microchip-MS devices are designed for bottom-up approaches or top-down proteomics. Here, we demonstrate a strategy for designing a microchip for top-down MS analysis of protein higher-order structures and dynamics. It is suitable for time-resolved native MS and HDX MS, with designs aiming for efficient ionization of intact protein complexes, flexible manipulation of multiple reactant flows, and precise control of reaction times over a broad range of flow rates on the submicroliter per minute scale. The performance of the prototype device is demonstrated by measurements of systems including monoclonal antibodies, antibody-antigen complexes, and coexisting protein conformers. This strategy may benefit elaborate structural analysis of biomacromolecules and inspire method development using the microchip-MS approach.
Collapse
Affiliation(s)
- Wen Li
- Research Center for Biomedical Optics and Molecular Imaging, Institute of Biomedical and Health Engineering, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Lingxiao Chaihu
- School of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210023, China.,Institute of Cell Analysis, Shenzhen Bay Laboratory, Shenzhen 518132, China
| | - Jialu Jiang
- School of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210023, China
| | - Bizhu Wu
- Research Center for Biomedical Optics and Molecular Imaging, Institute of Biomedical and Health Engineering, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Xuan Zheng
- Research Center for Biomedical Optics and Molecular Imaging, Institute of Biomedical and Health Engineering, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Rongrong Dai
- School of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210023, China
| | - Ye Tian
- Institute of Cell Analysis, Shenzhen Bay Laboratory, Shenzhen 518132, China
| | - Yanyi Huang
- Institute of Cell Analysis, Shenzhen Bay Laboratory, Shenzhen 518132, China.,Biomedical Pioneering Innovation Centre, Peking University, Beijing 100871, China
| | - Guanbo Wang
- Institute of Cell Analysis, Shenzhen Bay Laboratory, Shenzhen 518132, China.,Biomedical Pioneering Innovation Centre, Peking University, Beijing 100871, China
| | - Yongfan Men
- Research Center for Biomedical Optics and Molecular Imaging, Institute of Biomedical and Health Engineering, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| |
Collapse
|
2
|
Lento C, Wilson DJ. Subsecond Time-Resolved Mass Spectrometry in Dynamic Structural Biology. Chem Rev 2021; 122:7624-7646. [PMID: 34324314 DOI: 10.1021/acs.chemrev.1c00222] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Life at the molecular level is a dynamic world, where the key players-proteins, oligonucleotides, lipids, and carbohydrates-are in a perpetual state of structural flux, shifting rapidly between local minima on their conformational free energy landscapes. The techniques of classical structural biology, X-ray crystallography, structural NMR, and cryo-electron microscopy (cryo-EM), while capable of extraordinary structural resolution, are innately ill-suited to characterize biomolecules in their dynamically active states. Subsecond time-resolved mass spectrometry (MS) provides a unique window into the dynamic world of biological macromolecules, offering the capacity to directly monitor biochemical processes and conformational shifts with a structural dimension provided by the electrospray charge-state distribution, ion mobility, covalent labeling, or hydrogen-deuterium exchange. Over the past two decades, this suite of techniques has provided important insights into the inherently dynamic processes that drive function and pathogenesis in biological macromolecules, including (mis)folding, complexation, aggregation, ligand binding, and enzyme catalysis, among others. This Review provides a comprehensive account of subsecond time-resolved MS and the advances it has enabled in dynamic structural biology, with an emphasis on insights into the dynamic drivers of protein function.
Collapse
Affiliation(s)
- Cristina Lento
- Department of Chemistry, York University, Toronto, Ontario M3J 1P3, Canada
| | - Derek J Wilson
- Department of Chemistry, York University, Toronto, Ontario M3J 1P3, Canada
| |
Collapse
|
3
|
Bangaru S, Lang S, Schotsaert M, Vanderven HA, Zhu X, Kose N, Bombardi R, Finn JA, Kent SJ, Gilchuk P, Gilchuk I, Turner HL, García-Sastre A, Li S, Ward AB, Wilson IA, Crowe JE. A Site of Vulnerability on the Influenza Virus Hemagglutinin Head Domain Trimer Interface. Cell 2020; 177:1136-1152.e18. [PMID: 31100268 DOI: 10.1016/j.cell.2019.04.011] [Citation(s) in RCA: 159] [Impact Index Per Article: 39.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 02/25/2019] [Accepted: 04/04/2019] [Indexed: 12/17/2022]
Abstract
Here, we describe the discovery of a naturally occurring human antibody (Ab), FluA-20, that recognizes a new site of vulnerability on the hemagglutinin (HA) head domain and reacts with most influenza A viruses. Structural characterization of FluA-20 with H1 and H3 head domains revealed a novel epitope in the HA trimer interface, suggesting previously unrecognized dynamic features of the trimeric HA protein. The critical HA residues recognized by FluA-20 remain conserved across most subtypes of influenza A viruses, which explains the Ab's extraordinary breadth. The Ab rapidly disrupted the integrity of HA protein trimers, inhibited cell-to-cell spread of virus in culture, and protected mice against challenge with viruses of H1N1, H3N2, H5N1, or H7N9 subtypes when used as prophylaxis or therapy. The FluA-20 Ab has uncovered an exceedingly conserved protective determinant in the influenza HA head domain trimer interface that is an unexpected new target for anti-influenza therapeutics and vaccines.
Collapse
Affiliation(s)
- Sandhya Bangaru
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Shanshan Lang
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Michael Schotsaert
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Hillary A Vanderven
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
| | - Xueyong Zhu
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Nurgun Kose
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Robin Bombardi
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Jessica A Finn
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Stephen J Kent
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
| | - Pavlo Gilchuk
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Iuliia Gilchuk
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Hannah L Turner
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Adolfo García-Sastre
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Sheng Li
- Department of Medicine and Biomedical Sciences, School of Medicine, University of California, San Diego, CA 92093, USA
| | - Andrew B Ward
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Ian A Wilson
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA; The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.
| | - James E Crowe
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA; The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
| |
Collapse
|
4
|
Gilchuk IM, Bangaru S, Gilchuk P, Irving RP, Kose N, Bombardi RG, Thornburg NJ, Creech CB, Edwards KM, Li S, Turner HL, Yu W, Zhu X, Wilson IA, Ward AB, Crowe JE. Influenza H7N9 Virus Neuraminidase-Specific Human Monoclonal Antibodies Inhibit Viral Egress and Protect from Lethal Influenza Infection in Mice. Cell Host Microbe 2019; 26:715-728.e8. [PMID: 31757769 PMCID: PMC6941661 DOI: 10.1016/j.chom.2019.10.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 08/20/2019] [Accepted: 10/07/2019] [Indexed: 02/05/2023]
Abstract
H7N9 avian influenza virus causes severe infections and might have the potential to trigger a major pandemic. Molecular determinants of human humoral immune response to N9 neuraminidase (NA) proteins, which exhibit unusual features compared with seasonal influenza virus NA proteins, are ill-defined. We isolated 35 human monoclonal antibodies (mAbs) from two H7N9 survivors and two vaccinees. These mAbs react to NA in a subtype-specific manner and recognize diverse antigenic sites on the surface of N9 NA, including epitopes overlapping with, or distinct from, the enzyme active site. Despite recognizing multiple antigenic sites, the mAbs use a common mechanism of action by blocking egress of nascent virions from infected cells, thereby providing an antiviral prophylactic and therapeutic protection in vivo in mice. Studies of breadth, potency, and diversity of antigenic recognition from four subjects suggest that vaccination with inactivated adjuvanted vaccine induce NA-reactive responses comparable to that of H7N9 natural infection.
Collapse
Affiliation(s)
- Iuliia M Gilchuk
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Sandhya Bangaru
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Pavlo Gilchuk
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Ryan P Irving
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Nurgun Kose
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Robin G Bombardi
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Natalie J Thornburg
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - C Buddy Creech
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Kathryn M Edwards
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Sheng Li
- Department of Medicine, School of Medicine, University of California, San Diego, San Diego, CA 92093, USA
| | - Hannah L Turner
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Wenli Yu
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Xueyong Zhu
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Ian A Wilson
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA; Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Andrew B Ward
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - James E Crowe
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
| |
Collapse
|
5
|
Thornburg NJ, Zhang H, Bangaru S, Sapparapu G, Kose N, Lampley RM, Bombardi RG, Yu Y, Graham S, Branchizio A, Yoder SM, Rock MT, Creech CB, Edwards KM, Lee D, Li S, Wilson IA, García-Sastre A, Albrecht RA, Crowe JE. H7N9 influenza virus neutralizing antibodies that possess few somatic mutations. J Clin Invest 2016; 126:1482-94. [PMID: 26950424 PMCID: PMC4811156 DOI: 10.1172/jci85317] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Accepted: 01/21/2016] [Indexed: 01/08/2023] Open
Abstract
Avian H7N9 influenza viruses are group 2 influenza A viruses that have been identified as the etiologic agent for a current major outbreak that began in China in 2013 and may pose a pandemic threat. Here, we examined the human H7-reactive antibody response in 75 recipients of a monovalent inactivated A/Shanghai/02/2013 H7N9 vaccine. After 2 doses of vaccine, the majority of donors had memory B cells that secreted IgGs specific for H7 HA, with dominant responses against single HA subtypes, although frequencies of H7-reactive B cells ranged widely between donors. We isolated 12 naturally occurring mAbs with low half-maximal effective concentrations for binding, 5 of which possessed neutralizing and HA-inhibiting activities. The 5 neutralizing mAbs exhibited narrow breadth of reactivity with influenza H7 strains. Epitope-mapping studies using neutralization escape mutant analysis, deuterium exchange mass spectrometry, and x-ray crystallography revealed that these neutralizing mAbs bind near the receptor-binding pocket on HA. All 5 neutralizing mAbs possessed low numbers of somatic mutations, suggesting the clones arose from naive B cells. The most potent mAb, H7.167, was tested as a prophylactic treatment in a mouse intranasal virus challenge study, and systemic administration of the mAb markedly reduced viral lung titers.
Collapse
MESH Headings
- Adult
- Animals
- Antibodies, Monoclonal/genetics
- Antibodies, Monoclonal/immunology
- Antibodies, Neutralizing/genetics
- Antibodies, Neutralizing/immunology
- Antibodies, Viral/genetics
- Antibodies, Viral/immunology
- Binding Sites, Antibody/genetics
- Binding Sites, Antibody/immunology
- Epitope Mapping
- Epitopes/genetics
- Epitopes/immunology
- Female
- Humans
- Influenza A Virus, H7N9 Subtype/genetics
- Influenza A Virus, H7N9 Subtype/immunology
- Influenza Vaccines/administration & dosage
- Influenza Vaccines/genetics
- Influenza Vaccines/immunology
- Male
- Mice
- Middle Aged
- Mutation
Collapse
Affiliation(s)
- Natalie J. Thornburg
- The Vanderbilt Vaccine Center and
- Department of Pediatrics, Vanderbilt University, Nashville, Tennessee, USA
| | - Heng Zhang
- Department of Integrative Structural and Computational Biology and the Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California, USA
| | | | - Gopal Sapparapu
- The Vanderbilt Vaccine Center and
- Department of Pediatrics, Vanderbilt University, Nashville, Tennessee, USA
| | | | | | | | | | | | | | - Sandra M. Yoder
- The Vanderbilt Vaccine Center and
- Vanderbilt Vaccine Research Program, Vanderbilt University, Nashville, Tennessee, USA
| | - Michael T. Rock
- The Vanderbilt Vaccine Center and
- Department of Pediatrics, Vanderbilt University, Nashville, Tennessee, USA
- Vanderbilt Vaccine Research Program, Vanderbilt University, Nashville, Tennessee, USA
| | - C. Buddy Creech
- Department of Pediatrics, Vanderbilt University, Nashville, Tennessee, USA
- Vanderbilt Vaccine Research Program, Vanderbilt University, Nashville, Tennessee, USA
| | - Kathryn M. Edwards
- Department of Pediatrics, Vanderbilt University, Nashville, Tennessee, USA
- Vanderbilt Vaccine Research Program, Vanderbilt University, Nashville, Tennessee, USA
| | - David Lee
- Department of Medicine and Biomedical Sciences Graduate Program, School of Medicine, UCSD, San Diego, California, USA
| | - Sheng Li
- Department of Medicine and Biomedical Sciences Graduate Program, School of Medicine, UCSD, San Diego, California, USA
| | - Ian A. Wilson
- Department of Integrative Structural and Computational Biology and the Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California, USA
| | - Adolfo García-Sastre
- Department of Microbiology
- Global Health and Emerging Pathogens Institute, and
- Department of Medicine, Division of Infectious Diseases at Icahn School of Medicine at Mount Sinai (ISMMS), New York, New York, USA
| | - Randy A. Albrecht
- Department of Microbiology
- Global Health and Emerging Pathogens Institute, and
| | - James E. Crowe
- The Vanderbilt Vaccine Center and
- Department of Pediatrics, Vanderbilt University, Nashville, Tennessee, USA
- Departments of Pathology, Microbiology, and Immunology, and
| |
Collapse
|
6
|
Affiliation(s)
- Gregory
F. Pirrone
- Department of Chemistry and
Chemical Biology, Northeastern University, 360 Huntington Ave., Boston, Massachusetts 02115 United States
| | - Roxana E. Iacob
- Department of Chemistry and
Chemical Biology, Northeastern University, 360 Huntington Ave., Boston, Massachusetts 02115 United States
| | - John R. Engen
- Department of Chemistry and
Chemical Biology, Northeastern University, 360 Huntington Ave., Boston, Massachusetts 02115 United States
| |
Collapse
|
7
|
Abstract
This paper is the thirty-fifth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2012 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration and thermoregulation (Section 16); and immunological responses (Section 17).
Collapse
Affiliation(s)
- Richard J Bodnar
- Department of Psychology and Neuropsychology Doctoral Sub-Program, Queens College, City University of New York, Flushing, NY 11367, United States.
| |
Collapse
|
8
|
Differential accessibility of a rotavirus VP6 epitope in trimers comprising type I, II, or III channels as revealed by binding of a human rotavirus VP6-specific antibody. J Virol 2013; 88:469-76. [PMID: 24155406 DOI: 10.1128/jvi.01665-13] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Previous human antibody studies have shown that the human VH1-46 antibody variable gene segment encodes much of the naturally occurring human B cell response to rotavirus and is directed to virus protein 6 (VP6). It is currently unknown why some of the VH1-46-encoded human VP6 monoclonal antibodies inhibit viral transcription while others do not. In part, there are affinity differences between antibodies that likely affect inhibitory activity, but we also hypothesize that there are differing modes of binding to VP6 that affect the ability to block the transcriptional pore on double-layered particles. Here, we used a hybrid method approach for antibody epitope mapping, including single-particle cryo-electron microscopy (cryo-EM) and enhanced amide hydrogen-deuterium exchange mass spectrometry (DXMS) to determine the location and mode of binding of a VH1-46-encoded antibody, RV6-25. The structure of the RV6-25 antibody-double-layered particle (DLP) complex indicated a very complex binding pattern that revealed subtle differences in accessibility of the VP6 epitope depending on its position in the type I, II, or III channels. These subtle variations in the presentation or accessibility of the RV VP6 capsid layer led to position-specific differences in occupancy for binding of the RV6-25 antibody. The studies also showed that the location of binding of the noninhibitory antibody RV6-25 on the apical surface of RV VP6 head domain does not obstruct the transcription pore upon antibody binding, in contrast to binding of an inhibitory antibody, RV6-26, deeper in the transcriptional pore.
Collapse
|
9
|
Aiyegbo MS, Sapparapu G, Spiller BW, Eli IM, Williams DR, Kim R, Lee DE, Liu T, Li S, Woods VL, Nannemann DP, Meiler J, Stewart PL, Crowe JE. Human rotavirus VP6-specific antibodies mediate intracellular neutralization by binding to a quaternary structure in the transcriptional pore. PLoS One 2013; 8:e61101. [PMID: 23671563 PMCID: PMC3650007 DOI: 10.1371/journal.pone.0061101] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Accepted: 03/05/2013] [Indexed: 11/17/2022] Open
Abstract
Several live attenuated rotavirus (RV) vaccines have been licensed, but the mechanisms of protective immunity are still poorly understood. The most frequent human B cell response is directed to the internal protein VP6 on the surface of double-layered particles, which is normally exposed only in the intracellular environment. Here, we show that the canonical VP6 antibodies secreted by humans bind to such particles and inhibit viral transcription. Polymeric IgA RV antibodies mediated an inhibitory effect against virus replication inside cells during IgA transcytosis. We defined the recognition site on VP6 as a quaternary epitope containing a high density of charged residues. RV human mAbs appear to bind to a negatively-charged patch on the surface of the Type I channel in the transcriptionally active particle, and they sterically block the channel. This unique mucosal mechanism of viral neutralization, which is not apparent from conventional immunoassays, may contribute significantly to human immunity to RV.
Collapse
Affiliation(s)
- Mohammed S Aiyegbo
- Department of Pathology, Microbiology and Immunology, Vanderbilt Medical Center, Nashville, Tennessee, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|