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He Y, Guo Z, Subiaur S, Benegal A, Vahey MD. Antibody inhibition of influenza A virus assembly and release. J Virol 2024; 98:e0139823. [PMID: 38179944 PMCID: PMC10878280 DOI: 10.1128/jvi.01398-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Accepted: 12/01/2023] [Indexed: 01/06/2024] Open
Abstract
Antibodies are frontline defenders against influenza virus infection, providing protection through multiple complementary mechanisms. Although a subset of monoclonal antibodies (mAbs) has been shown to restrict replication at the level of virus assembly and release, it remains unclear how potent and pervasive this mechanism of protection is, due in part to the challenge of separating this effect from other aspects of antibody function. To address this question, we developed imaging-based assays to determine how effectively a broad range of mAbs against the IAV surface proteins can specifically restrict viral egress. We find that classically neutralizing antibodies against hemagglutinin are broadly multifunctional, inhibiting virus assembly and release at concentrations 1-20-fold higher than the concentrations at which they inhibit viral entry. These antibodies are also capable of altering the morphological features of shed virions, reducing the proportion of filamentous particles. We find that antibodies against neuraminidase and M2 also restrict viral egress and that inhibition by anti-neuraminidase mAbs is only partly attributable to a loss in enzymatic activity. In all cases, antigen crosslinking-either on the surface of the infected cell, between the viral and cell membrane, or both-plays a critical role in inhibition, and we are able to distinguish between these modes experimentally and through a structure-based computational model. Together, these results provide a framework for dissecting antibody multifunctionality that could help guide the development of improved therapeutic antibodies or vaccines and that can be extended to other viral families and antibody isotypes.IMPORTANCEAntibodies against influenza A virus provide multifaceted protection against infection. Although sensitive and quantitative assays are widely used to measure inhibition of viral attachment and entry, the ability of diverse antibodies to inhibit viral egress is less clear. We address this challenge by developing an imaging-based approach to measure antibody inhibition of virus release across a panel of monoclonal antibodies targeting the influenza A virus surface proteins. Using this approach, we find that inhibition of viral egress is common and can have similar potency to the ability of an antibody to inhibit viral entry. Insights into this understudied aspect of antibody function may help guide the development of improved countermeasures.
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Affiliation(s)
- Yuanyuan He
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri, USA
- Center for Biomolecular Condensates, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Zijian Guo
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri, USA
- Center for Biomolecular Condensates, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Sofie Subiaur
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri, USA
- Center for Biomolecular Condensates, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Ananya Benegal
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri, USA
- Center for Biomolecular Condensates, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Michael D. Vahey
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri, USA
- Center for Biomolecular Condensates, Washington University in St. Louis, St. Louis, Missouri, USA
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2
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Raju S, Adams LJ, Diamond MS. The many ways in which alphaviruses bind to cells. Trends Immunol 2024; 45:85-93. [PMID: 38135598 PMCID: PMC10997154 DOI: 10.1016/j.it.2023.11.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2023] [Revised: 11/25/2023] [Accepted: 11/26/2023] [Indexed: 12/24/2023]
Abstract
Only a subset of viruses can productively infect many different host species. Some arthropod-transmitted viruses, such as alphaviruses, can infect invertebrate and vertebrate species including insects, reptiles, birds, and mammals. This broad tropism may be explained by their ability to engage receptors that are conserved across vertebrate and invertebrate classes. Through several genome-wide loss-of-function screens, new alphavirus receptors have been identified, some of which bind to multiple related viruses in different antigenic complexes. Structural analysis has revealed that distinct sites on the alphavirus glycoprotein can mediate receptor binding, which opposes the idea that a single receptor-binding site mediates viral entry. Here, we discuss how different paradigms of receptor engagement on cells might explain the promiscuity of alphaviruses for multiple hosts.
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Affiliation(s)
- Saravanan Raju
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Lucas J Adams
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Michael S Diamond
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA; Andrew M. and Jane M. Bursky Center for Human Immunology and Immunotherapy Programs, Washington University School of Medicine, St. Louis, MO 63110, USA; Center for Vaccines and Immunity to Microbial Pathogens, Washington University School of Medicine, Saint Louis, MO 63110, USA.
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3
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Schwedler JL, Stefan MA, Thatcher CE, McIlroy PR, Sinha A, Phillips AM, Sumner CA, Courtney CM, Kim CY, Weilhammer DR, Harmon B. Therapeutic efficacy of a potent anti-Venezuelan equine encephalitis virus antibody is contingent on Fc effector function. MAbs 2024; 16:2297451. [PMID: 38170638 PMCID: PMC10766394 DOI: 10.1080/19420862.2023.2297451] [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: 10/27/2023] [Accepted: 12/15/2023] [Indexed: 01/05/2024] Open
Abstract
The development of specific, safe, and potent monoclonal antibodies (Abs) has led to novel therapeutic options for infectious disease. In addition to preventing viral infection through neutralization, Abs can clear infected cells and induce immunomodulatory functions through engagement of their crystallizable fragment (Fc) with complement proteins and Fc receptors on immune cells. Little is known about the role of Fc effector functions of neutralizing Abs in the context of encephalitic alphavirus infection. To determine the role of Fc effector function in therapeutic efficacy against Venezuelan equine encephalitis virus (VEEV), we compared the potently neutralizing anti-VEEV human IgG F5 (hF5) Ab with intact Fc function (hF5-WT) or containing the loss of function Fc mutations L234A and L235A (hF5-LALA) in the context of VEEV infection. We observed significantly reduced binding to complement and Fc receptors, as well as differential in vitro kinetics of Fc-mediated cytotoxicity for hF5-LALA compared to hF5-WT. The in vivo efficacy of hF5-LALA was comparable to hF5-WT at -24 and + 24 h post infection, with both Abs providing high levels of protection. However, when hF5-WT and hF5-LALA were administered + 48 h post infection, there was a significant decrease in the therapeutic efficacy of hF5-LALA. Together these results demonstrate that optimal therapeutic Ab treatment of VEEV, and possibly other encephalitic alphaviruses, requires neutralization paired with engagement of immune effectors via the Fc region.
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Affiliation(s)
- Jennifer L. Schwedler
- Biotechnology and Bioengineering Department, Sandia National Laboratories, Livermore, CA, USA
| | - Maxwell A. Stefan
- Biotechnology and Bioengineering Department, Sandia National Laboratories, Livermore, CA, USA
| | - Christine E. Thatcher
- Biotechnology and Bioengineering Department, Sandia National Laboratories, Livermore, CA, USA
| | - Peter R. McIlroy
- Biotechnology and Bioengineering Department, Sandia National Laboratories, Livermore, CA, USA
| | - Anupama Sinha
- Biotechnology and Bioengineering Department, Sandia National Laboratories, Livermore, CA, USA
| | - Ashlee M. Phillips
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Christopher A. Sumner
- Biotechnology and Bioengineering Department, Sandia National Laboratories, Livermore, CA, USA
| | - Colleen M. Courtney
- Biotechnology and Bioengineering Department, Sandia National Laboratories, Livermore, CA, USA
| | - Christina Y. Kim
- Biotechnology and Bioengineering Department, Sandia National Laboratories, Livermore, CA, USA
| | - Dina R. Weilhammer
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Brooke Harmon
- Biotechnology and Bioengineering Department, Sandia National Laboratories, Livermore, CA, USA
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4
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Kafai NM, Janova H, Cain MD, Alippe Y, Muraro S, Sariol A, Elam-Noll M, Klein RS, Diamond MS. Entry receptor LDLRAD3 is required for Venezuelan equine encephalitis virus peripheral infection and neurotropism leading to pathogenesis in mice. Cell Rep 2023; 42:112946. [PMID: 37556325 PMCID: PMC10529316 DOI: 10.1016/j.celrep.2023.112946] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 07/03/2023] [Accepted: 07/21/2023] [Indexed: 08/11/2023] Open
Abstract
Venezuelan equine encephalitis virus (VEEV) is an encephalitic alphavirus responsible for epidemics of neurological disease across the Americas. Low-density lipoprotein receptor class A domain-containing 3 (LDLRAD3) is a recently reported entry receptor for VEEV. Here, using wild-type and Ldlrad3-deficient mice, we define a critical role for LDLRAD3 in controlling steps in VEEV infection, pathogenesis, and neurotropism. Our analysis shows that LDLRAD3 is required for efficient VEEV infection and pathogenesis prior to and after central nervous system invasion. Ldlrad3-deficient mice survive intranasal and intracranial VEEV inoculation and show reduced infection of neurons in different brain regions. As LDLRAD3 is a determinant of pathogenesis and an entry receptor required for VEEV infection of neurons of the brain, receptor-targeted therapies may hold promise as countermeasures.
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Affiliation(s)
- Natasha M Kafai
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Hana Janova
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Matthew D Cain
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Yael Alippe
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Stefanie Muraro
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Alan Sariol
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Michelle Elam-Noll
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Robyn S Klein
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Neuroscience, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Michael S Diamond
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA; The Andrew M. and Jane M. Bursky Center for Human Immunology and Immunotherapy Programs, Washington University School of Medicine, St. Louis, MO 63110, USA.
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5
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Yuanyuan H, Zijian G, Subiaur S, Benegal A, Vahey MD. Antibody Inhibition of Influenza A Virus Assembly and Release. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.08.552198. [PMID: 37609131 PMCID: PMC10441363 DOI: 10.1101/2023.08.08.552198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
Antibodies are frontline defenders against influenza virus infection, providing protection through multiple complementary mechanisms. Although a subset of monoclonal antibodies (mAbs) have been shown to restrict replication at the level of virus assembly and release, it remains unclear how potent and pervasive this mechanism of protection is, due in part to the challenge of separating this effect from other aspects of antibody function. To address this question, we developed imaging-based assays to determine how effectively a broad range of mAbs against the IAV surface proteins can specifically restrict viral egress. We find that classically neutralizing antibodies against hemagglutinin are broadly multifunctional, inhibiting virus assembly and release at concentrations one- to twenty-fold higher than the concentrations at which they inhibit viral entry. These antibodies are also capable of altering the morphological features of shed virions, reducing the proportion of filamentous particles. We find that antibodies against neuraminidase and M2 also restrict viral egress, and that inhibition by anti-neuraminidase mAbs is only partly attributable to a loss in enzymatic activity. In all cases, antigen crosslinking - either on the surface of the infected cell, between the viral and cell membrane, or both - plays a critical role in inhibition, and we are able to distinguish between these modes experimentally and through a structure-based computational model. Together, these results provide a framework for dissecting antibody multifunctionality that could help guide the development of improved therapeutic antibodies or vaccines, and that can be extended to other viral families and antibody isotypes.
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Affiliation(s)
- He Yuanyuan
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri, USA
- Center for Biomolecular Condensates, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Guo Zijian
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri, USA
- Center for Biomolecular Condensates, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Sofie Subiaur
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri, USA
- Center for Biomolecular Condensates, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Ananya Benegal
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri, USA
- Center for Biomolecular Condensates, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Michael D. Vahey
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri, USA
- Center for Biomolecular Condensates, Washington University in St. Louis, St. Louis, Missouri, USA
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6
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Kim AS, Diamond MS. A molecular understanding of alphavirus entry and antibody protection. Nat Rev Microbiol 2023; 21:396-407. [PMID: 36474012 PMCID: PMC9734810 DOI: 10.1038/s41579-022-00825-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/01/2022] [Indexed: 12/12/2022]
Abstract
Alphaviruses are arthropod-transmitted RNA viruses that cause epidemics of human infection and disease on a global scale. These viruses are classified as either arthritogenic or encephalitic based on their genetic relatedness and the clinical syndromes they cause. Although there are currently no approved therapeutics or vaccines against alphaviruses, passive transfer of monoclonal antibodies confers protection in animal models. This Review highlights recent advances in our understanding of the host factors required for alphavirus entry, the mechanisms of action by which protective antibodies inhibit different steps in the alphavirus infection cycle and candidate alphavirus vaccines currently under clinical evaluation that focus on humoral immunity. A comprehensive understanding of alphavirus entry and antibody-mediated protection may inform the development of new classes of countermeasures for these emerging viruses.
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Affiliation(s)
- Arthur S Kim
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA, USA
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, USA
| | - Michael S Diamond
- Department of Medicine, Washington University School of Medicine, Saint Louis, MO, USA.
- Department of Pathology and Immunology, Washington University School of Medicine, Saint Louis, MO, USA.
- Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, MO, USA.
- The Andrew M. and Jane M. Bursky Center for Human Immunology and Immunotherapy Programs, Washington University School of Medicine, Saint Louis, MO, USA.
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Patel AR, Dulcey M, Abid N, Cash MN, Dailey J, Salemi M, Mavian C, Vittor AY. Infectivity of three Mayaro Virus geographic isolates in human cell lines. Acta Trop 2023; 242:106894. [PMID: 36965613 DOI: 10.1016/j.actatropica.2023.106894] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 03/07/2023] [Accepted: 03/12/2023] [Indexed: 03/27/2023]
Abstract
Mayaro virus (MAYV) is an emergent arthropod-borne virus that causes an acute febrile illness accompanied by arthralgia, similar to chikungunya virus. Increasing urbanization of MAYV outbreaks in the Americas has led to concerns for geographic expansion and spillover. Given the potential importance of this pathogen, we sought to fill critical gaps in knowledge regarding MAYV infectivity and geographic variation. This study describes the cytopathogenicity of MAYV in human dermal fibroblasts, human skeletal muscle satellite cells, human embryonic kidney cells (HEK), peripherally derived human macrophages, and Vero cells. We found that regional differences between these viruses do not affect replication kinetics, with high titers peaking at 37 h post infection. MAYV-U, did however, cause the most cytopathic effect in a time-dependent manner. Compared to the other two prototypic isolates, MAYV-U harbors unique mutations in the E2 protein, D60G and S205F, that are likely to interact with the host cell receptor and could affect infectivity. We further demonstrate that pre-treatment of cells with interferon-β inhibited viral replication in a dose-dependent manner. Together, these findings advance our understanding of MAYV infection of human target cells and provide initial data regarding variation according to geography.
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Affiliation(s)
- Aum R Patel
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Melissa Dulcey
- Department of Environmental and Global Health, University of Florida, Gainesville, FL, USA
| | - Nabil Abid
- High Institute of Biotechnology, University of Monastir, Tunisia; Faculty of Pharmacy of Monastir, Laboratory of Transmissible Diseases and Biological Active Substances, University of Monastir, Tunisia
| | - Melanie N Cash
- Department of Pathology, Immunology and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, FL, USA; Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
| | - Jordan Dailey
- College of Medicine, Virginia Commonwealth University, VA, USA
| | - Marco Salemi
- Department of Pathology, Immunology and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, FL, USA; Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
| | - Carla Mavian
- Department of Pathology, Immunology and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, FL, USA; Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA.
| | - Amy Y Vittor
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA; Division of Infectious Disease and Global Medicine, University of Florida, Gainesville, FL, USA.
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8
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Williamson LE, Bandyopadhyay A, Bailey K, Sirohi D, Klose T, Julander JG, Kuhn RJ, Crowe JE. Structural constraints link differences in neutralization potency of human anti-Eastern equine encephalitis virus monoclonal antibodies. Proc Natl Acad Sci U S A 2023; 120:e2213690120. [PMID: 36961925 PMCID: PMC10068833 DOI: 10.1073/pnas.2213690120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 02/10/2023] [Indexed: 03/26/2023] Open
Abstract
Selection and development of monoclonal antibody (mAb) therapeutics against pathogenic viruses depends on certain functional characteristics. Neutralization potency, or the half-maximal inhibitory concentration (IC50) values, is an important characteristic of candidate therapeutic antibodies. Structural insights into the bases of neutralization potency differences between antiviral neutralizing mAbs are lacking. In this report, we present cryo-electron microscopy (EM) reconstructions of three anti-Eastern equine encephalitis virus (EEEV) neutralizing human mAbs targeting overlapping epitopes on the E2 protein, with greater than 20-fold differences in their respective IC50 values. From our structural and biophysical analyses, we identify several constraints that contribute to the observed differences in the neutralization potencies. Cryo-EM reconstructions of EEEV in complex with these Fab fragments reveal structural constraints that dictate intravirion or intervirion cross-linking of glycoprotein spikes by their IgG counterparts as a mechanism of neutralization. Additionally, we describe critical features for the recognition of EEEV by these mAbs including the epitope-paratope interaction surface, occupancy, and kinetic differences in on-rate for binding to the E2 protein. Each constraint contributes to the extent of EEEV inhibition for blockade of virus entry, fusion, and/or egress. These findings provide structural and biophysical insights into the differences in mechanism and neutralization potencies of these antibodies, which help inform rational design principles for candidate vaccines and therapeutic antibodies for all icosahedral viruses.
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Affiliation(s)
- Lauren E. Williamson
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN37232
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University, Nashville, TN37232
| | - Abhishek Bandyopadhyay
- Purdue Institute of Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN47907
| | - Kevin Bailey
- Institute for Antiviral Research, Utah State University, Logan, UT84335
| | - Devika Sirohi
- Purdue Institute of Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN47907
| | - Thomas Klose
- Purdue Institute of Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN47907
| | | | - Richard J. Kuhn
- Purdue Institute of Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN47907
| | - James E. Crowe
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN37232
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University, Nashville, TN37232
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN37232
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9
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Schein CH, Rafael G, Baker WS, Anaya ES, Schmidt JG, Weaver SC, Negi S, Braun W. PCP consensus protein/peptide alphavirus antigens stimulate broad spectrum neutralizing antibodies. Peptides 2022; 157:170844. [PMID: 35878658 DOI: 10.1016/j.peptides.2022.170844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 07/18/2022] [Accepted: 07/19/2022] [Indexed: 11/18/2022]
Abstract
Vaccines based on proteins and peptides may be safer and if calculated based on many sequences, more broad-spectrum than those designed based on single strains. Physicochemical Property Consensus (PCPcon) alphavirus (AV) antigens from the B-domain of the E2 envelope protein were designed, synthesized recombinantly and shown to be immunogenic (i.e. sera after inoculation detected the antigen in dotspots and ELISA). Antibodies in sera after inoculation with B-region antigens based on individual AV species (eastern or Venezuelan equine encephalitis (EEEVcon, VEEVcon), or chikungunya (CHIKVcon) bound only their cognate protein, while those designed against multiple species (Mosaikcon and EVCcon) recognized all three serotype specific antigens. The VEEVcon and EEEVcon sera only showed antiviral activity against their related strains (in plaque reduction neutralization assays (PRNT50/80). Peptides designed to surface exposed areas of the E2-A-domain of CHIKVcon were added to CHIKVcon inocula to provide anti-CHIKV antibodies. EVCcon, based on three different alphavirus species, combined with E2-A-domain peptides from AllAVcon, a PCPcon of 24 diverse AV, generated broad spectrum, antiviral antibodies against VEEV, EEEV and CHIKV, AV with less than 35% amino acid identity to each other (>65% diversity). This is a promising start to a molecularly defined vaccine against all AV. Further study with these antigens can illuminate what areas are most important for a robust immune response, resistant to mutations in rapidly evolving viruses. The validated computational methods can also be used to design broad spectrum antigens against many other pathogen families.
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Affiliation(s)
- Catherine H Schein
- Departments of Biochemistry and Molecular Biology, UTMB; Institute for Human Infections and Immunity (IHII), UTMB; University of Texas Medical Branch at Galveston, 301 University Boulevard, Galveston, TX 77555, USA.
| | - Grace Rafael
- Microbiology and Immunology, UTMB; University of Texas Medical Branch at Galveston, 301 University Boulevard, Galveston, TX 77555, USA
| | - Wendy S Baker
- Departments of Biochemistry and Molecular Biology, UTMB; University of Texas Medical Branch at Galveston, 301 University Boulevard, Galveston, TX 77555, USA
| | | | | | - Scott C Weaver
- Microbiology and Immunology, UTMB; Institute for Human Infections and Immunity (IHII), UTMB; World Reference Center for Emerging Viruses and Arboviruses, UTMB; Sealy Center for Structural Biology and Molecular Biophysics, UTMB; University of Texas Medical Branch at Galveston, 301 University Boulevard, Galveston, TX 77555, USA
| | - Surendra Negi
- Departments of Biochemistry and Molecular Biology, UTMB; Sealy Center for Structural Biology and Molecular Biophysics, UTMB; University of Texas Medical Branch at Galveston, 301 University Boulevard, Galveston, TX 77555, USA
| | - Werner Braun
- Departments of Biochemistry and Molecular Biology, UTMB; Sealy Center for Structural Biology and Molecular Biophysics, UTMB; University of Texas Medical Branch at Galveston, 301 University Boulevard, Galveston, TX 77555, USA
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10
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Thompson D, Metz SW, Abad C, Beaty S, Warfield K. Immunological implications of diverse production approaches for Chikungunya virus-like particle vaccines. Vaccine 2022; 40:3009-3017. [PMID: 35459557 DOI: 10.1016/j.vaccine.2022.04.021] [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: 10/22/2021] [Revised: 03/04/2022] [Accepted: 04/04/2022] [Indexed: 11/17/2022]
Abstract
Chikungunya virus (CHIKV), an arbovirus from the Alphavirus genus, causes sporadic outbreaks and epidemics and can cause acute febrile illness accompanied by severe long-term arthralgias. Over 20 CHIKV vaccine candidates have been developed over the last two decades, utilizing a wide range of vaccine platforms, including virus-like particles (VLP). A CHIKV VLP vaccine candidate is among three candidates in late-stage clinical testing and has potentially promising data in nonclinical and clinical studies exploring safety and vaccine immunogenicity. Despite the consistency of the CHIKV VLP structure, vaccine candidates vary significantly in protein sequence identity, structural protein expression cassettes and their mode of production. Here, we explore the impact of CHIKV VLP coding sequence variation and the chosen expression platform, which affect VLP expression yields, antigenicity and overall vaccine immunogenicity. Additionally, we explore the potential of the CHIKV VLP platform to be modified to elicit protection against other pathogens.
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Affiliation(s)
- Danielle Thompson
- Emergent BioSolutions Inc., 400 Professional Dr, Gaithersburg, MD 20879, USA
| | - Stefan W Metz
- Emergent BioSolutions Inc., 400 Professional Dr, Gaithersburg, MD 20879, USA
| | - Carmen Abad
- Emergent BioSolutions Inc., 400 Professional Dr, Gaithersburg, MD 20879, USA
| | - Shannon Beaty
- Emergent BioSolutions Inc., 400 Professional Dr, Gaithersburg, MD 20879, USA
| | - Kelly Warfield
- Emergent BioSolutions Inc., 400 Professional Dr, Gaithersburg, MD 20879, USA.
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11
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Kafai NM, Williamson LE, Binshtein E, Sukupolvi-Petty S, Gardner CL, Liu J, Mackin S, Kim AS, Kose N, Carnahan RH, Jung A, Droit L, Reed DS, Handley SA, Klimstra WB, Crowe JE, Diamond MS. Neutralizing antibodies protect mice against Venezuelan equine encephalitis virus aerosol challenge. J Exp Med 2022; 219:e20212532. [PMID: 35297953 PMCID: PMC9195047 DOI: 10.1084/jem.20212532] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 01/31/2022] [Accepted: 02/01/2022] [Indexed: 11/24/2022] Open
Abstract
Venezuelan equine encephalitis virus (VEEV) remains a risk for epidemic emergence or use as an aerosolized bioweapon. To develop possible countermeasures, we isolated VEEV-specific neutralizing monoclonal antibodies (mAbs) from mice and a human immunized with attenuated VEEV strains. Functional assays and epitope mapping established that potently inhibitory anti-VEEV mAbs bind distinct antigenic sites in the A or B domains of the E2 glycoprotein and block multiple steps in the viral replication cycle including attachment, fusion, and egress. A 3.2-Å cryo-electron microscopy reconstruction of VEEV virus-like particles bound by a human Fab suggests that antibody engagement of the B domain may result in cross-linking of neighboring spikes to prevent conformational requirements for viral fusion. Prophylaxis or postexposure therapy with these mAbs protected mice against lethal aerosol challenge with VEEV. Our study defines functional and structural mechanisms of mAb protection and suggests that multiple antigenic determinants on VEEV can be targeted for vaccine or antibody-based therapeutic development.
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Affiliation(s)
- Natasha M. Kafai
- Department of Medicine, Washington University School of Medicine, St. Louis, MO
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO
| | - Lauren E. Williamson
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN
| | - Elad Binshtein
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN
| | | | - Christina L. Gardner
- Center for Vaccine Research, University of Pittsburgh, Pittsburgh, PA
- Department of Immunology, University of Pittsburgh, Pittsburgh, PA
- United States Army Research Institute for Infectious Diseases, Fort Detrick, MD
| | - Jaclyn Liu
- Department of Medicine, Washington University School of Medicine, St. Louis, MO
| | - Samantha Mackin
- Department of Medicine, Washington University School of Medicine, St. Louis, MO
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO
| | - Arthur S. Kim
- Department of Medicine, Washington University School of Medicine, St. Louis, MO
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO
| | - Nurgun Kose
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN
| | - Robert H. Carnahan
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN
| | - Ana Jung
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO
| | - Lindsay Droit
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO
| | - Douglas S. Reed
- Center for Vaccine Research, University of Pittsburgh, Pittsburgh, PA
- Department of Immunology, University of Pittsburgh, Pittsburgh, PA
| | - Scott A. Handley
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO
| | - William B. Klimstra
- Center for Vaccine Research, University of Pittsburgh, Pittsburgh, PA
- Department of Immunology, University of Pittsburgh, Pittsburgh, PA
| | - James E. Crowe
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN
| | - Michael S. Diamond
- Department of Medicine, Washington University School of Medicine, St. Louis, MO
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO
- The Andrew M. and Jane M. Bursky Center for Human Immunology and Immunotherapy Programs, Washington University School of Medicine, St. Louis, MO
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12
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Haines CA, Campos RK, Azar SR, Warmbrod KL, Kautz TF, Forrester NL, Rossi SL. Venezuelan Equine Encephalitis Virus V3526 Vaccine RNA-Dependent RNA Polymerase Mutants Increase Vaccine Safety Through Restricted Tissue Tropism in a Murine Model. ZOONOSES (BURLINGTON, MASS.) 2022; 2:2. [PMID: 35262074 PMCID: PMC8900488 DOI: 10.15212/zoonoses-2021-0016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
BACKGROUND Venezuelan equine encephalitis virus (VEEV) is an arbovirus endemic to the Americas. There are no approved vaccines or antivirals. TC-83 and V3526 are the best-characterized vaccine candidates for VEEV. Both are live-attenuated vaccines and have been associated with safety concerns, albeit less so for V3526. A previous attempt to improve the TC-83 vaccine focused on further attenuating the vaccine by adding mutations that altered the error incorporation rate of the RNA-dependent RNA polymerase (RdRp). METHODS The research presented here examines the impact of these RdRp mutations in V3526 by cloning the 3X and 4X strains, assessing vaccine efficacy against challenge in adult female CD-1 mice, examining neutralizing antibody titers, investigating vaccine tissue tropism, and testing the stability of the mutant strains. RESULTS Our results show that the V3526 RdRp mutants exhibited reduced tissue tropism in the spleen and kidney compared to wild-type V3526, while maintaining vaccine efficacy. Illumina sequencing showed that the RdRp mutations could revert to wild-type V3526. CONCLUSIONS The observed genotypic reversion is likely of limited concern because wild-type V3526 is still an effective vaccine capable of providing protection. Our results indicate that the V3526 RdRp mutants may be a safer vaccine design than the original V3526.
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Affiliation(s)
- Clint A. Haines
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Rafael K. Campos
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Sasha R. Azar
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - K. Lane Warmbrod
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Tiffany F. Kautz
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Naomi L. Forrester
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Shannan L. Rossi
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, 77555, USA
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, 77555, USA
- Institute for Human Infection and Immunity, University of Texas Medical Branch, Galveston, TX, 77555, USA
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13
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Structure of Venezuelan equine encephalitis virus in complex with the LDLRAD3 receptor. Nature 2021; 598:672-676. [PMID: 34646020 PMCID: PMC8550936 DOI: 10.1038/s41586-021-03963-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 08/26/2021] [Indexed: 11/10/2022]
Abstract
LDLRAD3 is a recently defined attachment and entry receptor for Venezuelan equine encephalitis virus (VEEV)1, a New World alphavirus that causes severe neurological disease in humans. Here we present near-atomic-resolution cryo-electron microscopy reconstructions of VEEV virus-like particles alone and in a complex with the ectodomains of LDLRAD3. Domain 1 of LDLRAD3 is a low-density lipoprotein receptor type-A module that binds to VEEV by wedging into a cleft created by two adjacent E2–E1 heterodimers in one trimeric spike, and engages domains A and B of E2 and the fusion loop in E1. Atomic modelling of this interface is supported by mutagenesis and anti-VEEV antibody binding competition assays. Notably, VEEV engages LDLRAD3 in a manner that is similar to the way that arthritogenic alphaviruses bind to the structurally unrelated MXRA8 receptor, but with a much smaller interface. These studies further elucidate the structural basis of alphavirus–receptor interactions, which could inform the development of therapies to mitigate infection and disease against multiple members of this family. The structure of the Venezuelan equine encephalitis virus in complex with LDLRAD3 provides insights into the structural basis of alphavirus–receptor interactions.
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14
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Calvert AE, Bennett SL, Hunt AR, Fong RH, Doranz BJ, Roehrig JT, Blair CD. Exposing cryptic epitopes on the Venezuelan equine encephalitis virus E1 glycoprotein prior to treatment with alphavirus cross-reactive monoclonal antibody allows blockage of replication early in infection. Virology 2021; 565:13-21. [PMID: 34626907 PMCID: PMC8765347 DOI: 10.1016/j.virol.2021.09.007] [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: 05/23/2021] [Revised: 09/20/2021] [Accepted: 09/24/2021] [Indexed: 01/17/2023]
Abstract
Eastern equine encephalitis virus (EEEV), western equine encephalitis virus (WEEV) and Venezuelan equine encephalitis virus (VEEV) can cause fatal encephalitis in humans and equids. Some MAbs to the E1 glycoprotein are known to be cross-reactive, weakly neutralizing in vitro but can protect from disease in animal models. We investigated the mechanism of neutralization of VEEV infection by the broadly cross-reactive E1-specific MAb 1A4B-6. 1A4B-6 protected 3-week-old Swiss Webster mice prophylactically from lethal VEEV challenge. Likewise, 1A4B-6 inhibited virus growth in vitro at a pre-attachment step after virions were incubated at 37 °C and inhibited virus-mediated cell fusion. Amino acid residue N100 in the fusion loop of E1 protein was identified as critical for binding. The potential to elicit broadly cross-reactive MAbs with limited virus neutralizing activity in vitro but that can inhibit virus entry and protect animals from infection merits further exploration for vaccine and therapeutic developmental research.
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Affiliation(s)
- Amanda E Calvert
- Arboviral Diseases Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, CO 80521, USA.
| | - Susan L Bennett
- Center for Vector-borne Infectious Diseases, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA
| | - Ann R Hunt
- Center for Vector-borne Infectious Diseases, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA
| | | | | | - John T Roehrig
- Center for Vector-borne Infectious Diseases, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA
| | - Carol D Blair
- Center for Vector-borne Infectious Diseases, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA
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15
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Williamson LE, Reeder KM, Bailey K, Tran MH, Roy V, Fouch ME, Kose N, Trivette A, Nargi RS, Winkler ES, Kim AS, Gainza C, Rodriguez J, Armstrong E, Sutton RE, Reidy J, Carnahan RH, McDonald WH, Schoeder CT, Klimstra WB, Davidson E, Doranz BJ, Alter G, Meiler J, Schey KL, Julander JG, Diamond MS, Crowe JE. Therapeutic alphavirus cross-reactive E1 human antibodies inhibit viral egress. Cell 2021; 184:4430-4446.e22. [PMID: 34416147 PMCID: PMC8418820 DOI: 10.1016/j.cell.2021.07.033] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 04/11/2021] [Accepted: 07/26/2021] [Indexed: 12/11/2022]
Abstract
Alphaviruses cause severe arthritogenic or encephalitic disease. The E1 structural glycoprotein is highly conserved in these viruses and mediates viral fusion with host cells. However, the role of antibody responses to the E1 protein in immunity is poorly understood. We isolated E1-specific human monoclonal antibodies (mAbs) with diverse patterns of recognition for alphaviruses (ranging from Eastern equine encephalitis virus [EEEV]-specific to alphavirus cross-reactive) from survivors of natural EEEV infection. Antibody binding patterns and epitope mapping experiments identified differences in E1 reactivity based on exposure of epitopes on the glycoprotein through pH-dependent mechanisms or presentation on the cell surface prior to virus egress. Therapeutic efficacy in vivo of these mAbs corresponded with potency of virus egress inhibition in vitro and did not require Fc-mediated effector functions for treatment against subcutaneous EEEV challenge. These studies reveal the molecular basis for broad and protective antibody responses to alphavirus E1 proteins.
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MESH Headings
- Alphavirus/immunology
- Animals
- Antibodies, Monoclonal/immunology
- Antibodies, Monoclonal/isolation & purification
- Antibodies, Neutralizing/immunology
- Antibodies, Viral/immunology
- Antigens, Viral/immunology
- Cell Line
- Chikungunya virus/immunology
- Cross Reactions/immunology
- Encephalitis Virus, Eastern Equine/immunology
- Encephalomyelitis, Equine/immunology
- Encephalomyelitis, Equine/virology
- Epitope Mapping
- Female
- Horses
- Humans
- Hydrogen-Ion Concentration
- Joints/pathology
- Male
- Mice, Inbred C57BL
- Models, Biological
- Protein Binding
- RNA, Viral/metabolism
- Receptors, Fc/metabolism
- Temperature
- Viral Proteins/immunology
- Virion/metabolism
- Virus Internalization
- Virus Release/physiology
- Mice
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Affiliation(s)
- Lauren E Williamson
- Department of Pathology, Microbiology and Immunology, Vanderbilt University, Nashville, TN 37232, USA; The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Kristen M Reeder
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Kevin Bailey
- Institute for Antiviral Research, Utah State University, Logan, UT 84335, USA
| | - Minh H Tran
- Chemical and Physical Biology Program, Vanderbilt University, Nashville, TN, USA; Center of Structural Biology, Vanderbilt University, Nashville, TN, USA; Department of Biochemistry and Mass Spectrometry Research Center, Vanderbilt University, Nashville, TN, USA
| | - Vicky Roy
- Ragon Institute of MGH, MIT, and Harvard University, Cambridge, MA 02139, USA
| | | | - Nurgun Kose
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Andrew Trivette
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Rachel S Nargi
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Emma S Winkler
- Department of Medicine, Washington University, St. Louis, MO 63110, USA; Department of Pathology and Immunology, Washington University, St. Louis, MO 63110, USA
| | - Arthur S Kim
- Department of Medicine, Washington University, St. Louis, MO 63110, USA; Department of Pathology and Immunology, Washington University, St. Louis, MO 63110, USA
| | - Christopher Gainza
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Jessica Rodriguez
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Erica Armstrong
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Rachel E Sutton
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Joseph Reidy
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Robert H Carnahan
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - W Hayes McDonald
- Department of Biochemistry and Mass Spectrometry Research Center, Vanderbilt University, Nashville, TN, USA
| | - Clara T Schoeder
- Center of Structural Biology, Vanderbilt University, Nashville, TN, USA; Department of Chemistry, Vanderbilt University, Nashville, TN, USA
| | - William B Klimstra
- The Center for Vaccine Research, University of Pittsburgh, Pittsburgh, PA 165261, USA; Department of Immunology, University of Pittsburgh, Pittsburgh, PA 165261, USA
| | | | | | - Galit Alter
- Ragon Institute of MGH, MIT, and Harvard University, Cambridge, MA 02139, USA
| | - Jens Meiler
- Center of Structural Biology, Vanderbilt University, Nashville, TN, USA; Department of Chemistry, Vanderbilt University, Nashville, TN, USA; Institute for Drug Discovery, Leipzig University Medical School, Leipzig, Germany
| | - Kevin L Schey
- Department of Biochemistry and Mass Spectrometry Research Center, Vanderbilt University, Nashville, TN, USA
| | - Justin G Julander
- Institute for Antiviral Research, Utah State University, Logan, UT 84335, USA
| | - Michael S Diamond
- Department of Medicine, Washington University, St. Louis, MO 63110, USA; Department of Pathology and Immunology, Washington University, St. Louis, MO 63110, USA; Department of Molecular Microbiology, Washington University, St. Louis, MO 63110, USA
| | - James E Crowe
- Department of Pathology, Microbiology and Immunology, Vanderbilt University, Nashville, TN 37232, USA; Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37232, USA; The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
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16
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Hasan SS, Dey D, Singh S, Martin M. The Structural Biology of Eastern Equine Encephalitis Virus, an Emerging Viral Threat. Pathogens 2021; 10:pathogens10080973. [PMID: 34451437 PMCID: PMC8400090 DOI: 10.3390/pathogens10080973] [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: 06/01/2021] [Revised: 07/21/2021] [Accepted: 07/28/2021] [Indexed: 11/16/2022] Open
Abstract
Alphaviruses are arboviruses that cause arthritis and encephalitis in humans. Eastern Equine Encephalitis Virus (EEEV) is a mosquito-transmitted alphavirus that is implicated in severe encephalitis in humans with high mortality. However, limited insights are available into the fundamental biology of EEEV and residue-level details of its interactions with host proteins. In recent years, outbreaks of EEEV have been reported mainly in the United States, raising concerns about public safety. This review article summarizes recent advances in the structural biology of EEEV based mainly on single-particle cryogenic electron microscopy (cryoEM) structures. Together with functional analyses of EEEV and related alphaviruses, these structural investigations provide clues to how EEEV interacts with host proteins, which may open avenues for the development of therapeutics.
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Affiliation(s)
- S. Saif Hasan
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 N. Greene Street, Baltimore, MD 21201, USA; (D.D.); (S.S.); (M.M.)
- Center for Biomolecular Therapeutics, University of Maryland School of Medicine, 9600 Gudelsky Drive, Rockville, MD 20850, USA
- University of Maryland Marlene and Stewart Greenebaum Cancer Center, University of Maryland Medical Center, 22. S. Greene St., Baltimore, MD 21201, USA
- Correspondence:
| | - Debajit Dey
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 N. Greene Street, Baltimore, MD 21201, USA; (D.D.); (S.S.); (M.M.)
| | - Suruchi Singh
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 N. Greene Street, Baltimore, MD 21201, USA; (D.D.); (S.S.); (M.M.)
| | - Matthew Martin
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 N. Greene Street, Baltimore, MD 21201, USA; (D.D.); (S.S.); (M.M.)
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17
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Chikungunya-specific IgG and neutralizing antibody responses in natural infection of Chikungunya virus in children from India. Arch Virol 2021; 166:1913-1920. [PMID: 33907861 DOI: 10.1007/s00705-021-05049-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 02/08/2021] [Indexed: 09/29/2022]
Abstract
Chikungunya virus (CHIKV) infection is endemic in many different countries. CHIKV outbreaks are emerging in new areas and re-emerging in previously exposed geographical regions, thus making it a significant public health concern. CHIKV infections are often clinically inapparent, especially in children, which poses a challenge to testing and evaluating any vaccine. During CHIKV infection, CHIKV-specific antibodies are produced, and some of these antibodies can neutralize viruses released from infected cells before they can enter uninfected cells. In this study, we evaluated IgG binding and neutralizing antibody responses in paired serum samples from CHIKV-infected children and those with other febrile illness, using a recombinant truncated E2 protein and whole CHIKV particles as test antigens. Antibody detection using the truncated E2 protein showed a significant overlap between CHIKV-infected subjects and those with other febrile illnesses. This overlap was greater when binding antibody titers were determined using fixed CHIKV particles as the test antigen. Acute- and convalescent-phase sera collected from children after CHIKV infection showed significant differences in their neutralizing capacity. The neutralizing and binding antibody response showed a significant positive correlation. We detected IgG antibodies in most cases during the acute phase of infection. This was observed at two different geographical locations, one of which is not considered highly endemic. Conventional wisdom would suggest this to be a marker of re-infection (secondary infection). However, dissenting opinions have been voiced in other viral diseases (such as Ebola) where studies have detected IgG in acute illness. In the absence of any significant body of work documenting secondary CHIKV infections, we believe further work is needed to understand the early IgG response that we observed.
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18
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Silva MK, Gomes HSS, Silva OLT, Campanelli SE, Campos DMO, Araújo JMG, Fernandes JV, Fulco UL, Oliveira JIN. Identification of promiscuous T cell epitopes on Mayaro virus structural proteins using immunoinformatics, molecular modeling, and QM:MM approaches. INFECTION GENETICS AND EVOLUTION 2021; 91:104826. [PMID: 33781966 DOI: 10.1016/j.meegid.2021.104826] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Revised: 03/11/2021] [Accepted: 03/23/2021] [Indexed: 10/21/2022]
Abstract
The Mayaro virus (MAYV) belongs to genus Alphavirus (family Togaviridae) and has been reported in several countries, especially in tropical regions of America. Due to its outbreaks and potential lack of medication, an effective vaccine formulation is strongly required. This study aimed to predict promiscuous T cell epitopes from structural polyproteins of MAYV using an immunoinformatics approach. For this purpose, consensus sequences were used to identify short protein sequences capable of binding to MHC class I and class II alleles. Our analysis pointed out 4 MHC-I/TCD8+ and 21 MHC-II/TCD4+ epitopes on capside (1;3), E1 (2;5), E2 (1;10), E3 (0;2), and 6 K (0;1) proteins. These predicted epitopes were characterized by high antigenicity, immunogenicity, conservancy, non-allergenic, non-toxic, and good population coverage rate values for North and South American geographical areas. Afterwards, we used the crystal structure of human toll-like receptor 3 (TLR3) ectodomain as a template to predict, through docking essays, the placement of a vaccine prototype at the TLR3 receptor binding site. Finally, classical and quantum mechanics/molecular mechanics (QM:MM) computations were employed to improve the quality of docking calculations, with the QM part of the simulations being accomplished by using the density functional theory (DFT) formalism. These results provide important insights into the advancement of diagnostic platforms, the development of vaccines, and immunotherapeutic interventions.
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Affiliation(s)
- Maria K Silva
- Departamento de Biofísica e Farmacologia, Universidade Federal do Rio Grande do Norte, 59072-970 Natal, RN, Brazil
| | - Heloísa S S Gomes
- Departamento de Biofísica e Farmacologia, Universidade Federal do Rio Grande do Norte, 59072-970 Natal, RN, Brazil
| | - Ohana L T Silva
- Departamento de Biofísica e Farmacologia, Universidade Federal do Rio Grande do Norte, 59072-970 Natal, RN, Brazil
| | - Stephany E Campanelli
- Departamento de Biofísica e Farmacologia, Universidade Federal do Rio Grande do Norte, 59072-970 Natal, RN, Brazil
| | - Daniel M O Campos
- Departamento de Biofísica e Farmacologia, Universidade Federal do Rio Grande do Norte, 59072-970 Natal, RN, Brazil
| | - Josélio M G Araújo
- Departamento de Microbiologia e Parasitologia, Universidade Federal do Rio Grande do Norte, 59072-970 Natal, RN, Brazil
| | - José V Fernandes
- Departamento de Microbiologia e Parasitologia, Universidade Federal do Rio Grande do Norte, 59072-970 Natal, RN, Brazil
| | - Umberto L Fulco
- Departamento de Biofísica e Farmacologia, Universidade Federal do Rio Grande do Norte, 59072-970 Natal, RN, Brazil
| | - Jonas I N Oliveira
- Departamento de Biofísica e Farmacologia, Universidade Federal do Rio Grande do Norte, 59072-970 Natal, RN, Brazil.
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19
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Read CM, Plante K, Rafael G, Rossi SL, Braun W, Weaver SC, Schein CH. Designing multivalent immunogens for alphavirus vaccine optimization. Virology 2021; 561:117-124. [PMID: 33823988 DOI: 10.1016/j.virol.2020.11.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 10/15/2020] [Accepted: 11/22/2020] [Indexed: 11/16/2022]
Abstract
There is a pressing need for vaccines against mosquito-borne alphaviruses such as Venezualen and eastern equine encephalitis viruses (VEEV, EEEV). We demonstrate an approach to vaccine development based on physicochemical properties (PCP) of amino acids to design a PCP-consensus sequence of the epitope-rich B domain of the VEEV major antigenic E2 protein. The consensus "spike" domain was incorporated into a live-attenuated VEEV vaccine candidate (ZPC/IRESv1). Mice inoculated with either ZPC/IRESv1 or the same virus containing the consensus E2 protein fragment (VEEVconE2) were protected against lethal challenge with VEEV strains ZPC-738 and 3908, and Mucambo virus (MUCV, related to VEEV), and had comparable neutralizing antibody titers against each virus. Both vaccines induced partial protection against Madariaga virus (MADV), a close relative of EEEV, lowering mortality from 60% to 20%. Thus PCP-consensus sequences can be integrated into a replicating virus that could, with further optimization, provide a broad-spectrum vaccine against encephalitic alphaviruses.
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Affiliation(s)
- C M Read
- Department of Microbiology and Immunology, University of Texas Medical Branch at Galveston, 301 University Boulevard, Galveston, TX, 77555, USA
| | - Kenneth Plante
- Department of Microbiology and Immunology, University of Texas Medical Branch at Galveston, 301 University Boulevard, Galveston, TX, 77555, USA; Institute for Human Infections and Immunity (IHII), University of Texas Medical Branch at Galveston, 301 University Boulevard, Galveston, TX, 77555, USA; World Reference Center for Emerging Viruses and Arboviruses, University of Texas Medical Branch at Galveston, 301 University Boulevard, Galveston, TX, 77555, USA
| | - Grace Rafael
- Department of Microbiology and Immunology, University of Texas Medical Branch at Galveston, 301 University Boulevard, Galveston, TX, 77555, USA
| | - Shannan L Rossi
- Department of Microbiology and Immunology, University of Texas Medical Branch at Galveston, 301 University Boulevard, Galveston, TX, 77555, USA; Department of Pathology, University of Texas Medical Branch at Galveston, 301 University Boulevard, Galveston, TX, 77555, USA; Institute for Human Infections and Immunity (IHII), University of Texas Medical Branch at Galveston, 301 University Boulevard, Galveston, TX, 77555, USA
| | - Werner Braun
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch at Galveston, 301 University Boulevard, Galveston, TX, 77555, USA; Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch at Galveston, 301 University Boulevard, Galveston, TX, 77555, USA
| | - Scott C Weaver
- Department of Microbiology and Immunology, University of Texas Medical Branch at Galveston, 301 University Boulevard, Galveston, TX, 77555, USA; Institute for Human Infections and Immunity (IHII), University of Texas Medical Branch at Galveston, 301 University Boulevard, Galveston, TX, 77555, USA; World Reference Center for Emerging Viruses and Arboviruses, University of Texas Medical Branch at Galveston, 301 University Boulevard, Galveston, TX, 77555, USA; Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch at Galveston, 301 University Boulevard, Galveston, TX, 77555, USA
| | - Catherine H Schein
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch at Galveston, 301 University Boulevard, Galveston, TX, 77555, USA; Institute for Human Infections and Immunity (IHII), University of Texas Medical Branch at Galveston, 301 University Boulevard, Galveston, TX, 77555, USA.
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20
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Williamson LE, Gilliland T, Yadav PK, Binshtein E, Bombardi R, Kose N, Nargi RS, Sutton RE, Durie CL, Armstrong E, Carnahan RH, Walker LM, Kim AS, Fox JM, Diamond MS, Ohi MD, Klimstra WB, Crowe JE. Human Antibodies Protect against Aerosolized Eastern Equine Encephalitis Virus Infection. Cell 2020; 183:1884-1900.e23. [PMID: 33301709 DOI: 10.1016/j.cell.2020.11.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 09/23/2020] [Accepted: 11/06/2020] [Indexed: 12/19/2022]
Abstract
Eastern equine encephalitis virus (EEEV) is one of the most virulent viruses endemic to North America. No licensed vaccines or antiviral therapeutics are available to combat this infection, which has recently shown an increase in human cases. Here, we characterize human monoclonal antibodies (mAbs) isolated from a survivor of natural EEEV infection with potent (<20 pM) inhibitory activity of EEEV. Cryo-electron microscopy reconstructions of two highly neutralizing mAbs, EEEV-33 and EEEV-143, were solved in complex with chimeric Sindbis/EEEV virions to 7.2 Å and 8.3 Å, respectively. The mAbs recognize two distinct antigenic sites that are critical for inhibiting viral entry into cells. EEEV-33 and EEEV-143 protect against disease following stringent lethal aerosol challenge of mice with highly pathogenic EEEV. These studies provide insight into the molecular basis for the neutralizing human antibody response against EEEV and can facilitate development of vaccines and candidate antibody therapeutics.
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Affiliation(s)
- Lauren E Williamson
- Department of Pathology, Microbiology and Immunology, Vanderbilt University, Nashville, TN 37232, USA
| | - Theron Gilliland
- The Center for Vaccine Research, University of Pittsburgh, Pittsburgh, PA 165261, USA
| | - Pramod K Yadav
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Elad Binshtein
- 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
| | - Nurgun Kose
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Rachel S Nargi
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Rachel E Sutton
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Clarissa L Durie
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Erica Armstrong
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Robert H Carnahan
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Lauren M Walker
- Department of Pathology, Microbiology and Immunology, Vanderbilt University, Nashville, TN 37232, USA
| | - Arthur S Kim
- Department of Medicine, Washington University, St. Louis, MO 63110, USA; Department of Pathology and Immunology, Washington University, St. Louis, MO 63110, USA
| | - Julie M Fox
- Department of Medicine, Washington University, St. Louis, MO 63110, USA
| | - Michael S Diamond
- Department of Medicine, Washington University, St. Louis, MO 63110, USA; Department of Pathology and Immunology, Washington University, St. Louis, MO 63110, USA; Department of Molecular Microbiology, Washington University, St. Louis, MO 63110, USA
| | - Melanie D Ohi
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - William B Klimstra
- The Center for Vaccine Research, University of Pittsburgh, Pittsburgh, PA 165261, USA; Department of Immunology, University of Pittsburgh, Pittsburgh, PA 165261, USA
| | - James E Crowe
- Department of Pathology, Microbiology and Immunology, Vanderbilt University, 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.
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21
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Baker WS, Negi S, Braun W, Schein CH. Producing physicochemical property consensus alphavirus protein antigens for broad spectrum vaccine design. Antiviral Res 2020; 182:104905. [PMID: 32800880 DOI: 10.1016/j.antiviral.2020.104905] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 06/19/2020] [Accepted: 08/01/2020] [Indexed: 12/16/2022]
Abstract
There is a pressing need for new vaccines against alphaviruses, which can cause fatal encephalitis (Venezuelan equine encephalitis virus (VEEV) and others) and severe arthralgia (e.g. Chikungunya virus, CHIKV). These positive-strand RNA viruses are diverse and evolve rapidly, meaning that the sequence of any vaccine should cover multiple strains that may be quite different from any previous isolate. Here, consensus proteins were produced to represent the common physicochemical properties (PCPs) of the epitope rich, B domain of the E2 envelope protein. PCP-consensus proteins were based on multiple strains of VEEV (VEEVcon) and CHIKV (CHIKVcon) or the conserved PCPs of 24 different alphaviruses (AllAVcon). The AllAVcon was altered to include binding sites for neutralizing antibodies of both VEEV and CHIKV strains (Mosaikcon). All four designed proteins were produced solubly in E. coli and purified. They formed the β-strand core expected from experimental structures of this region of the wild type E2 proteins as indicated by circular dichroism (CD) spectra. Furthermore, the CHIKVcon protein bound to a structure dependent, CHIKV neutralizing monoclonal antibody. The AllAVcon and Mosaikcon proteins bound to polyclonal antibodies generated during natural infection with either VEEV or CHIKV, indicating they contained epitopes of both serotypes. The Mosaikcon antigen induced antibodies in rabbit sera that recognized both the VEEVcon and CHIKVcon spike proteins. These PCP-consensus antigens are promising starting points for novel, broad-spectrum alphavirus vaccines.
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Affiliation(s)
- Wendy S Baker
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Surendra Negi
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, 77555, USA; Sealy Center for Structural Biology, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Werner Braun
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, 77555, USA; Sealy Center for Structural Biology, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Catherine H Schein
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, 77555, USA; Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX, 77555, USA.
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22
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Cryo-EM Structures of Eastern Equine Encephalitis Virus Reveal Mechanisms of Virus Disassembly and Antibody Neutralization. Cell Rep 2019; 25:3136-3147.e5. [PMID: 30540945 PMCID: PMC6302666 DOI: 10.1016/j.celrep.2018.11.067] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 10/01/2018] [Accepted: 11/15/2018] [Indexed: 01/08/2023] Open
Abstract
Alphaviruses are enveloped pathogens that cause arthritis and encephalitis. Here, we report a 4.4-Å cryoelectron microscopy (cryo-EM) structure of eastern equine encephalitis virus (EEEV), an alphavirus that causes fatal encephalitis in humans. Our analysis provides insights into viral entry into host cells. The envelope protein E2 showed a binding site for the cellular attachment factor heparan sulfate. The presence of a cryptic E2 glycan suggests how EEEV escapes surveillance by lectin-expressing myeloid lineage cells, which are sentinels of the immune system. A mechanism for nucleocapsid core release and disassembly upon viral entry was inferred based on pH changes and capsid dissociation from envelope proteins. The EEEV capsid structure showed a viral RNA genome binding site adjacent to a ribosome binding site for viral genome translation following genome release. Using five Fab-EEEV complexes derived from neutralizing antibodies, our investigation provides insights into EEEV host cell interactions and protective epitopes relevant to vaccine design. EEEV cryo-EM structure shows the basis of receptor binding and pH-triggered disassembly Cryptic envelope protein glycosylation interferes with immune detection EEEV RNA genome binding site on capsid protein has an extended conformation Antibody inhibition of EEEV entry involves cross-linking of viral envelope proteins
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23
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Earnest JT, Basore K, Roy V, Bailey AL, Wang D, Alter G, Fremont DH, Diamond MS. Neutralizing antibodies against Mayaro virus require Fc effector functions for protective activity. J Exp Med 2019; 216:2282-2301. [PMID: 31337735 PMCID: PMC6781005 DOI: 10.1084/jem.20190736] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 06/11/2019] [Accepted: 06/20/2019] [Indexed: 01/01/2023] Open
Abstract
Despite causing outbreaks of fever and arthritis in multiple countries, no countermeasures exist against Mayaro virus (MAYV), an emerging mosquito-transmitted alphavirus. We generated 18 neutralizing mAbs against MAYV, 11 of which had "elite" activity that inhibited infection with EC50 values of <10 ng/ml. Antibodies with the greatest inhibitory capacity in cell culture mapped to epitopes near the fusion peptide of E1 and in domain B of the E2 glycoproteins. Unexpectedly, many of the elite neutralizing mAbs failed to prevent MAYV infection and disease in vivo. Instead, the most protective mAbs bound viral antigen on the cell surface with high avidity and promoted specific Fc effector functions, including phagocytosis by neutrophils and monocytes. In subclass switching studies, murine IgG2a and humanized IgG1 mAb variants controlled infection better than murine IgG1 and humanized IgG1-N297Q variants. An optimally protective antibody response to MAYV and possibly other alphaviruses may require tandem virus neutralization by the Fab moiety and effector functions of the Fc region.
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Affiliation(s)
- James T Earnest
- Department of Medicine, Washington University School of Medicine, St. Louis, MO
| | - Katherine Basore
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO
| | - Vicky Roy
- Ragon Institute of Massachusetts General Hospital, Massachusetts Institute of Technology, and Harvard University, Cambridge, MA
| | - Adam L Bailey
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO
| | - David Wang
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO
| | - Galit Alter
- Ragon Institute of Massachusetts General Hospital, Massachusetts Institute of Technology, and Harvard University, Cambridge, MA
| | - Daved H Fremont
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO
| | - Michael S Diamond
- Department of Medicine, Washington University School of Medicine, St. Louis, MO
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO
- The Andrew M. and Jane M. Bursky Center for Human Immunology and Immunotherapy Programs, Washington University School of Medicine, St. Louis, MO
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24
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Stass R, Ng WM, Kim YC, Huiskonen JT. Structures of enveloped virions determined by cryogenic electron microscopy and tomography. Adv Virus Res 2019; 105:35-71. [PMID: 31522708 PMCID: PMC7112279 DOI: 10.1016/bs.aivir.2019.07.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Enveloped viruses enclose their genomes inside a lipid bilayer which is decorated by membrane proteins that mediate virus entry. These viruses display a wide range of sizes, morphologies and symmetries. Spherical viruses are often isometric and their envelope proteins follow icosahedral symmetry. Filamentous and pleomorphic viruses lack such global symmetry but their surface proteins may display locally ordered assemblies. Determining the structures of enveloped viruses, including the envelope proteins and their protein-protein interactions on the viral surface, is of paramount importance. These structures can reveal how the virions are assembled and released by budding from the infected host cell, how the progeny virions infect new cells by membrane fusion, and how antibodies bind surface epitopes to block infection. In this chapter, we discuss the uses of cryogenic electron microscopy (cryo-EM) in elucidating structures of enveloped virions. Starting from a detailed outline of data collection and processing strategies, we highlight how cryo-EM has been successfully utilized to provide unique insights into enveloped virus entry, assembly, and neutralization.
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Affiliation(s)
- Robert Stass
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Weng M Ng
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Young Chan Kim
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Juha T Huiskonen
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom; Helsinki Institute of Life Science HiLIFE and Research Programme in Molecular and Integrative Biosciences, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.
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25
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Development of an Enzyme-Linked Immunosorbent Assay To Detect Antibodies Targeting Recombinant Envelope Protein 2 of Mayaro Virus. J Clin Microbiol 2019; 57:JCM.01892-18. [PMID: 30787146 DOI: 10.1128/jcm.01892-18] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 02/08/2019] [Indexed: 12/11/2022] Open
Abstract
Mayaro virus (MAYV) is a neglected arthropod-borne virus (arbovirus) antigenically clustered into the Semliki Forest complex group of Alphavirus genus (Togaviridae family), maintained in an unclear zoonotic cycle involving mosquitoes from Haemagogus genus as the main vector. The genome is composed of a positive single-stranded RNA of 11.5 kb in length, which contains two genes that encode four nonstructural (nsP1 to nsP4) and five structural (C, E3, E2, 6K, and E1) proteins. In the present study, we have developed an enzyme-linked immunosorbent assay (ELISA) using as antigen the recombinant envelope protein 2 of MAYV produced in an Escherichia coli system (rE2-MAYV ELISAs). A panel of 68 human serum samples from suspected arboviral cases was analyzed and titrated for anti-MAYV IgM and IgG antibody detection. The rE2-MAYV ELISA detected 33.8% (23/68) IgG-positive samples, demonstrating 100% sensitivity and 78.95% specificity compared to the MAYV-specific 50% plaque reduction neutralization assay. In addition, the positive MAYV-neutralizing samples showed high titers of detection by rE2-MAYV ELISA, suggesting a highly sensitive test. The rE2-MAYV ELISA also detected 42.5% (29/68) IgM-positive samples, of which 13.8% (4/29) presented high-avidity interactions with rE2-MAYV. Cross-reactivity was observed with Chikungunya virus (CHIKV)-specific murine antibody sample but not with CHIKV-specific human and other Alphavirus murine antibodies. In short, we have developed a rapid, simple, specific, and sensitive MAYV rE2-ELISA, and our preliminary results show its potential applicability to diagnosis of MAYV infections.
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26
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Jin J, Simmons G. Antiviral Functions of Monoclonal Antibodies against Chikungunya Virus. Viruses 2019; 11:v11040305. [PMID: 30925717 PMCID: PMC6520934 DOI: 10.3390/v11040305] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 03/25/2019] [Accepted: 03/27/2019] [Indexed: 12/24/2022] Open
Abstract
Chikungunya virus (CHIKV) is the most common alphavirus infecting humans worldwide. Antibodies play pivotal roles in the immune response to infection. Increasingly, therapeutic antibodies are becoming important for protection from pathogen infection for which neither vaccine nor treatment is available, such as CHIKV infection. The new generation of ultra-potent and/or broadly cross-reactive monoclonal antibodies (mAbs) provides new opportunities for intervention. In the past decade, several potent human and mouse anti-CHIKV mAbs were isolated and demonstrated to be protective in vivo. Mechanistic studies of these mAbs suggest that mAbs exert multiple modes of action cooperatively. Better understanding of these antiviral mechanisms for mAbs will help to optimize mAb therapies.
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Affiliation(s)
- Jing Jin
- Vitalant Research Institute, San Francisco, CA 94118, USA.
- Department of Pathology and Laboratory Medicine, University of California, San Francisco, CA 94143, USA.
| | - Graham Simmons
- Vitalant Research Institute, San Francisco, CA 94118, USA.
- Department of Pathology and Laboratory Medicine, University of California, San Francisco, CA 94143, USA.
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27
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Sharma A, Knollmann-Ritschel B. Current Understanding of the Molecular Basis of Venezuelan Equine Encephalitis Virus Pathogenesis and Vaccine Development. Viruses 2019; 11:v11020164. [PMID: 30781656 PMCID: PMC6410161 DOI: 10.3390/v11020164] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 01/30/2019] [Accepted: 02/07/2019] [Indexed: 12/30/2022] Open
Abstract
Dedication This review is dedicated in the memory of Dr Radha K. Maheshwari, a great mentor and colleague, whose passion for research and student training has left a lasting effect on this manuscript and many other works. Abstract Venezuelan equine encephalitis virus (VEEV) is an alphavirus in the family Togaviridae. VEEV is highly infectious in aerosol form and a known bio-warfare agent that can cause severe encephalitis in humans. Periodic outbreaks of VEEV occur predominantly in Central and South America. Increased interest in VEEV has resulted in a more thorough understanding of the pathogenesis of this disease. Inflammation plays a paradoxical role of antiviral response as well as development of lethal encephalitis through an interplay between the host and viral factors that dictate virus replication. VEEV has efficient replication machinery that adapts to overcome deleterious mutations in the viral genome or improve interactions with host factors. In the last few decades there has been ongoing development of various VEEV vaccine candidates addressing the shortcomings of the current investigational new drugs or approved vaccines. We review the current understanding of the molecular basis of VEEV pathogenesis and discuss various types of vaccine candidates.
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Affiliation(s)
- Anuj Sharma
- Department of Pathology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA.
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28
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Protective antibodies against Eastern equine encephalitis virus bind to epitopes in domains A and B of the E2 glycoprotein. Nat Microbiol 2018; 4:187-197. [PMID: 30455470 PMCID: PMC6294662 DOI: 10.1038/s41564-018-0286-4] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2018] [Accepted: 10/10/2018] [Indexed: 12/21/2022]
Abstract
Eastern equine encephalitis virus (EEEV) is a mosquito-transmitted alphavirus with a high case mortality rate in humans. EEEV is a biodefense concern because of its potential for aerosol spread and the lack of existing countermeasures. In this study, we identified a panel of 18 neutralizing murine monoclonal antibodies (mAbs) against the EEEV E2 protein, several of which had “elite” activity with 50% and 99% inhibitory concentrations (EC50 and EC99) of less than 10 and 100 ng/ml, respectively. Alanine-scanning mutagenesis and neutralization escape mapping analysis revealed epitopes for these mAbs in domains A or B of the E2 glycoprotein. A majority of the neutralizing mAbs blocked at a post-attachment stage, with several inhibiting viral membrane fusion. Administration of one dose of anti-EEEV mAbs protected mice from lethal subcutaneous or aerosol challenge. These experiments define the mechanistic basis for neutralization by protective anti-EEEV mAbs and suggest a path forward for treatment and vaccine design.
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29
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Broad and long-lasting immune protection against various Chikungunya genotypes demonstrated by participants in a cross-sectional study in a Cambodian rural community. Emerg Microbes Infect 2018; 7:13. [PMID: 29410416 PMCID: PMC5837154 DOI: 10.1038/s41426-017-0010-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 11/29/2017] [Accepted: 12/03/2017] [Indexed: 12/15/2022]
Abstract
Chikungunya virus (CHIKV) is an alphavirus circulating worldwide. Its presence in Asia has been reported since the 1950s, constituting the Asian genotype. Since 2005, strains from the Eastern, Central, and Southern African (ECSA) genotype have caused several outbreaks across Asia. Viruses from the ECSA genotype were also detected in Cambodia in late 2011 and led to an outbreak in a rural community in 2012. A former investigation from 2012 found a higher risk of infection in people younger than 40 years, suggesting a pre-existing herd immunity in the older Cambodian population due to infection with an Asian genotype. In 2016, we collected serum from equivalent numbers of individuals born before 1975 and born after 1980 that were also part of the 2012 study. We analyzed the 154 serum samples from 2016 for neutralization against the Cambodian ECSA isolate and three strains belonging to the Asian genotype. This experiment revealed that 22.5% (18/80) of the younger study participants had no CHIKV antibodies, whereas 5.4% (4/74) of the older population remained naive. Study participants infected during the ECSA outbreak had twofold neutralizing titers against the ECSA and the most ancient Asian genotype virus (Thailand 1958) compared to the other two Asian genotype viruses. The neutralization data also support the older population’s exposure to an Asian genotype virus during the 1960s. The observed cross-reactivity confirms that the investigated CHIKV strains belong to a single serotype despite the emergence of novel ECSA genotype viruses and supports the importance of the development of a Chikungunya vaccine.
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30
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Mangala Prasad V, Klose T, Rossmann MG. Assembly, maturation and three-dimensional helical structure of the teratogenic rubella virus. PLoS Pathog 2017; 13:e1006377. [PMID: 28575072 PMCID: PMC5470745 DOI: 10.1371/journal.ppat.1006377] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 06/14/2017] [Accepted: 04/25/2017] [Indexed: 01/24/2023] Open
Abstract
Viral infections during pregnancy are a significant cause of infant morbidity and mortality. Of these, rubella virus infection is a well-substantiated example that leads to miscarriages or severe fetal defects. However, structural information about the rubella virus has been lacking due to the pleomorphic nature of the virions. Here we report a helical structure of rubella virions using cryo-electron tomography. Sub-tomogram averaging of the surface spikes established the relative positions of the viral glycoproteins, which differed from the earlier icosahedral models of the virus. Tomographic analyses of in vitro assembled nucleocapsids and virions provide a template for viral assembly. Comparisons of immature and mature virions show large rearrangements in the glycoproteins that may be essential for forming the infectious virions. These results present the first known example of a helical membrane-enveloped virus, while also providing a structural basis for its assembly and maturation pathway. Rubella virus (RV) causes serious fetal defects when contracted during pregnancy. Despite its medical importance, due to the irregular shapes and different sizes of the virions, the RV structure has remained unknown. Using cryo-electron tomography, we have determined the RV structure, which shows a unique, helical outer surface. Subsequent local averaging of the RV surface spikes has established the conformations of its immunogenic glycoproteins. In vitro assembly studies on the virus capsid protein have provided insights into the interactions necessary for virus assembly. Comparisons between mature and immature RV show large conformational changes in the virion structure that are essential for virus maturation. These results help to gain a structural understanding of RV pathogenicity, which may also be relevant to other teratogenic viruses.
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Affiliation(s)
- Vidya Mangala Prasad
- Department of Biological Sciences, 240 S. Martin Jischke Drive, Purdue University, West Lafayette, IN, United States of America
| | - Thomas Klose
- Department of Biological Sciences, 240 S. Martin Jischke Drive, Purdue University, West Lafayette, IN, United States of America
| | - Michael G. Rossmann
- Department of Biological Sciences, 240 S. Martin Jischke Drive, Purdue University, West Lafayette, IN, United States of America
- * E-mail:
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31
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Weber C, Berberich E, von Rhein C, Henß L, Hildt E, Schnierle BS. Identification of Functional Determinants in the Chikungunya Virus E2 Protein. PLoS Negl Trop Dis 2017; 11:e0005318. [PMID: 28114368 PMCID: PMC5289616 DOI: 10.1371/journal.pntd.0005318] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 02/02/2017] [Accepted: 01/10/2017] [Indexed: 11/20/2022] Open
Abstract
Background Chikungunya virus (CHIKV) is a mosquito-transmitted alphavirus that causes high fever, rash, and recurrent arthritis in humans. It has efficiently adapted to Aedes albopictus, which also inhabits temperate regions, including Europe and the United States of America. In the past, CHIKV has mainly affected developing countries, but has recently caused large outbreaks in the Caribbean and Latin America. No treatment or licensed CHIKV vaccine exists. Methodology/Principal Findings Here, we have identified determinants in the CHIKV cell-attachment protein E2 that facilitate cell binding. The extracellular part of the E2 gene is subdivided into the three domains, A, B, and C. These domains were expressed in E. coli and as Fc-fusion proteins generated from HEK293T cells and used for cell-binding assays. Domains A and B bound to all cells tested, independently of their permissiveness to CHIKV infection. Domain C did not bind to cells at all. Furthermore, CHIKV cell entry was promoted by cell-surface glycosaminoglycans (GAGs) and domain B interacted exclusively with GAG-expressing cells. Domain A also bound, although only moderately, to GAG-deficient cells. Soluble GAGs were able to inhibit CHIKV infection up to 90%; however, they enhanced the transduction rate of CHIKV Env pseudotyped vectors in GAG-negative cells. Conclusion/Significance These data imply that CHIKV uses at least two mechanisms to enter cells, one GAG-dependent, via initial attachment through domain B, and the other GAG-independent, via attachment of domain A. These data give indications that CHIKV uses multiple mechanisms to enter cells and shows the potential of GAGs as lead structures for developing antiviral drugs. The chikungunya virus (CHIKV) glycoprotein E2 mediates cell attachment and consists of three domains A, B and C. Since the cell entry process of CHIKV is not understood in detail, we analyzed the binding properties of the three E2 domains with proteins expressed in E. coli or as Fc-fusion proteins and the role of glycosaminoglycans (GAGs) on E2 cell binding and CHIKV entry. The two surface-exposed E2 domains, A and B, both bound to cells and domain B bound only to cells expressing GAGs. Domain A bound additionally to GAG-deficient cells and domain C did not bind to cells. CHIKV-pseudotyped lentiviral vector and CHIKV entry were enhanced in cells expressing GAGs. Our results suggest that CHIKV uses at least two entry mechanisms, one GAG-dependent, via attachment through E2 domain B, and the other GAG-independent, via binding of domain A. These data give indications that CHIKV uses multiple mechanisms to enter cells and shows the potential of GAGs as lead structures for developing antiviral drugs. In addition, it shows that domain A and B might constitute good targets for vaccine development.
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Affiliation(s)
- Christopher Weber
- Paul-Ehrlich-Institut, Department of Virology, Paul-Ehrlich Strasse, Langen, Germany
| | - Eva Berberich
- Paul-Ehrlich-Institut, Department of Virology, Paul-Ehrlich Strasse, Langen, Germany
| | - Christine von Rhein
- Paul-Ehrlich-Institut, Department of Virology, Paul-Ehrlich Strasse, Langen, Germany
| | - Lisa Henß
- Paul-Ehrlich-Institut, Department of Virology, Paul-Ehrlich Strasse, Langen, Germany
| | - Eberhard Hildt
- Paul-Ehrlich-Institut, Department of Virology, Paul-Ehrlich Strasse, Langen, Germany
| | - Barbara S. Schnierle
- Paul-Ehrlich-Institut, Department of Virology, Paul-Ehrlich Strasse, Langen, Germany
- * E-mail:
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Dennehy JJ. Evolutionary ecology of virus emergence. Ann N Y Acad Sci 2016; 1389:124-146. [PMID: 28036113 PMCID: PMC7167663 DOI: 10.1111/nyas.13304] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Revised: 10/24/2016] [Accepted: 11/09/2016] [Indexed: 12/22/2022]
Abstract
The cross-species transmission of viruses into new host populations, termed virus emergence, is a significant issue in public health, agriculture, wildlife management, and related fields. Virus emergence requires overlap between host populations, alterations in virus genetics to permit infection of new hosts, and adaptation to novel hosts such that between-host transmission is sustainable, all of which are the purview of the fields of ecology and evolution. A firm understanding of the ecology of viruses and how they evolve is required for understanding how and why viruses emerge. In this paper, I address the evolutionary mechanisms of virus emergence and how they relate to virus ecology. I argue that, while virus acquisition of the ability to infect new hosts is not difficult, limited evolutionary trajectories to sustained virus between-host transmission and the combined effects of mutational meltdown, bottlenecking, demographic stochasticity, density dependence, and genetic erosion in ecological sinks limit most emergence events to dead-end spillover infections. Despite the relative rarity of pandemic emerging viruses, the potential of viruses to search evolutionary space and find means to spread epidemically and the consequences of pandemic viruses that do emerge necessitate sustained attention to virus research, surveillance, prophylaxis, and treatment.
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Affiliation(s)
- John J Dennehy
- Biology Department, Queens College of the City University of New York, Queens, New York and The Graduate Center of the City University of New York, New York, New York
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Legler PM, Compton JR, Hale ML, Anderson GP, Olson MA, Millard CB, Goldman ER. Stability of isolated antibody-antigen complexes as a predictive tool for selecting toxin neutralizing antibodies. MAbs 2016; 9:43-57. [PMID: 27660893 PMCID: PMC5240650 DOI: 10.1080/19420862.2016.1236882] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Ricin is an A-B ribosome inactivating protein (RIP) toxin composed of an A-chain subunit (RTA) that contains a catalytic N-glycosidase and a B-chain (RTB) lectin domain that binds cell surface glycans. Ricin exploits retrograde transport to enter into the Golgi and the endoplasmic reticulum, and then dislocates into the cytoplasm where it can reach its substrate, the rRNA. A subset of isolated antibodies (Abs) raised against the RTA subunit protect against ricin intoxication, and RTA-based vaccine immunogens have been shown to provide long-lasting protective immunity against the holotoxin. Anti-RTA Abs are unlikely to cross a membrane and reach the cytoplasm to inhibit the enzymatic activity of the A-chain. Moreover, there is not a strict correlation between the apparent binding affinity (Ka) of anti-RTA Abs and their ability to successfully neutralize ricin toxicity. Some anti-RTA antibodies are toxin-neutralizing, whereas others are not. We hypothesize that neutralizing anti-RTA Abs may interfere selectively with conformational change(s) or partial unfolding required for toxin internalization. To test this hypothesis, we measured the melting temperatures (Tm) of neutralizing single-domain Ab (sdAb)-antigen (Ag) complexes relative to the Tm of the free antigen (Tm-shift = Tmcomplex – TmAg), and observed increases in the Tmcomplex of 9–20 degrees. In contrast, non-neutralizing sdAb-Ag complexes shifted the TmComplex by only 6–7 degrees. A strong linear correlation (r2 = 0.992) was observed between the magnitude of the Tm-shift and the viability of living cells treated with the sdAb and ricin holotoxin. The Tm-shift of the sdAb-Ag complex provided a quantitative biophysical parameter that could be used to predict and rank-order the toxin-neutralizing activities of Abs. We determined the first structure of an sdAb-RTA1-33/44-198 complex, and examined other sdAb-RTA complexes. We found that neutralizing sdAb bound to regions involved in the early stages of unfolding. These Abs likely interfere with steps preceding or following endocytosis that require conformational changes. This method may have utility for the characterization or rapid screening of other Ab that act to prevent conformational changes or unfolding as part of their mechanism of action.
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Affiliation(s)
| | | | - Martha L Hale
- c US Army Medical Research Institute of Infectious Diseases , Frederick , MD , USA
| | | | - Mark A Olson
- c US Army Medical Research Institute of Infectious Diseases , Frederick , MD , USA
| | - Charles B Millard
- c US Army Medical Research Institute of Infectious Diseases , Frederick , MD , USA
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Rodas JD, Kautz T, Camacho E, Paternina L, Guzmán H, Díaz FJ, Blanco P, Tesh R, Weaver SC. Genetic Characterization of Northwestern Colombian Chikungunya Virus Strains from the 2014-2015 Epidemic. Am J Trop Med Hyg 2016; 95:639-46. [PMID: 27430542 DOI: 10.4269/ajtmh.16-0091] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2016] [Accepted: 06/06/2016] [Indexed: 12/25/2022] Open
Abstract
Chikungunya fever, an acute and often chronic arthralgic disease caused by the mosquito-borne alphavirus, chikungunya virus (CHIKV), spread into the Americas in late 2013. Since then it has caused epidemics in nearly all New World countries, the second largest being Colombia with over 450,000 suspected cases beginning in September, 2014, and focused in Bolivar Department in the north. We examined 32 human sera from suspected cases, including diverse age groups and both genders, and sequenced the CHIKV envelope glycoprotein genes, known determinants of vector host range. As expected for Asian lineage CHIKV strains, these isolates lacked known Aedes albopictus-adaptive mutations. All the Colombian strains were closely related to those from the Virgin Islands, Saint Lucia, Mexico, Puerto Rico, and Brazil, consistent with a single, point-source introduction from the southeast Asia/Pacific region. Two substitutions in the E2 and E1 envelope glycoprotein genes were found in the Colombian strains, especially E1-K211E involving a residue shown previously to affect epistatically the penetrance of the E1-A226V A. albopictus-adaptive substitution. We also identified two amino acid substitutions unique to all American CHIKV sequences: E2-V368A and 6K-L20M. Only one codon, 6K-47, had a high nonsynonymous substitution rate suggesting positive selection.
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Affiliation(s)
- Juan D Rodas
- Grupo Centauro, Facultad de Ciencias Agrarias, Universidad de Antioquia, Medellín, Colombia
| | - Tiffany Kautz
- Department of Pathology, Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, Texas. Department of Microbiology and Immunology, Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, Texas
| | - Erwin Camacho
- Grupo de Investigaciónes Biomédicas, Universidad de Sucre, Sincelejo, Colombia
| | - Luis Paternina
- Grupo de Investigaciónes Biomédicas, Universidad de Sucre, Sincelejo, Colombia
| | - Hilda Guzmán
- Department of Pathology, Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, Texas
| | - Francisco J Díaz
- Grupo de Inmunovirología, Facultad de Medicina, Universidad de Antioquia, Medellín, Colombia
| | - Pedro Blanco
- Grupo de Investigaciónes Biomédicas, Universidad de Sucre, Sincelejo, Colombia
| | - Robert Tesh
- Department of Pathology, Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, Texas
| | - Scott C Weaver
- Department of Pathology, Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, Texas. Department of Microbiology and Immunology, Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, Texas.
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Inhibitory Antibodies Targeting Emerging Viruses: Advancements and Mechanisms. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2016; 23:535-9. [PMID: 27226280 DOI: 10.1128/cvi.00136-16] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
From Ebola virus outbreaks in Western Africa to the introduction of chikungunya and Zika viruses in the Americas, new and neglected viruses continue to emerge and spread around the world. Due to a lack of existing vaccines or specific therapeutics, little other than supportive care and attempts to interrupt transmission can be provided during initial outbreaks. This has prompted a shift in vaccine design and development to identify novel epitopes and mechanisms of protection that may offer a broader range of protection against groups or whole families of viruses. Receptor-binding domains and other motifs within viral envelope proteins represent one excellent opportunity to target communal epitopes shared by related viruses. Similarly, for viruses where envelope participates in driving viral egress from infected cells, shared epitopes need to be identified to guide the development of broadly protective antibodies and vaccines. Here, we discuss recent advances in our understanding of broadly protective humoral responses for emerging viruses.
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Martin AC, Rees AR. Extracting human antibody sequences from public databases for antibody humanization: high frequency of species assignment errors. Protein Eng Des Sel 2016; 29:403-408. [DOI: 10.1093/protein/gzw018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 05/09/2016] [Indexed: 11/13/2022] Open
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Mérour E, Lamoureux A, Biacchesi S, Brémont M. Fine mapping of a salmonid E2 alphavirus neutralizing epitope. J Gen Virol 2016; 97:893-900. [PMID: 26801972 DOI: 10.1099/jgv.0.000411] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In this study, we aimed to characterize the epitope recognized by the neutralizing 17H23 mAb directed against the E2 glycoprotein of most of salmonid alphavirus (SAV) subtypes and widely used in several laboratories to routinely diagnose SAV. We hypothesized that the 17H23 epitope was located in the major domain B, previously identified in the E2 of mammalian alphaviruses as the domain recognized by most of the E2 neutralizing mAbs. Indeed, the SAV E2 domain B counterpart is contained in the protein domain previously characterized as being recognized by mAb 17H23. Thus, to precisely characterize the 17H23 epitope, we developed an alanine scanning mutagenesis approach coupled with the generation of the respective recombinant SAV (rSAV) by using the available infectious cDNA. Ten mutant rSAVs termed A-J from E2 aa 223-236 were produced and characterized in vitro using indirect immunofluorescence assays on virus-infected cells with mAbs 17H23, 51B8 (another non-neutralizing anti-E2 mAb) and 19F3 directed against the non-structural protein nsp1. Two of the mutant rSAVs (G and H) escaped neutralization by mAb 17H23. In addition, we showed that when juvenile trout were infected by bath immersion with the rSAV mutants, some of them were either totally (D, E and G) or partially (H) attenuated. Together, the data from the in vitro and in vivo experiments indicated that the putative 17H23 amino acid sequence epitope comprised the short amino acid sequence (227)FTSDS(231).
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Affiliation(s)
- Emilie Mérour
- VIM, INRA, Université Paris-Saclay, 78350 Jouy-en-Josas, France
| | - Annie Lamoureux
- VIM, INRA, Université Paris-Saclay, 78350 Jouy-en-Josas, France
| | | | - Michel Brémont
- VIM, INRA, Université Paris-Saclay, 78350 Jouy-en-Josas, France
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Long F, Fong RH, Austin SK, Chen Z, Klose T, Fokine A, Liu Y, Porta J, Sapparapu G, Akahata W, Doranz BJ, Crowe JE, Diamond MS, Rossmann MG. Cryo-EM structures elucidate neutralizing mechanisms of anti-chikungunya human monoclonal antibodies with therapeutic activity. Proc Natl Acad Sci U S A 2015; 112:13898-903. [PMID: 26504196 PMCID: PMC4653152 DOI: 10.1073/pnas.1515558112] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Chikungunya virus (CHIKV) is a mosquito-transmitted alphavirus that causes severe acute and chronic disease in humans. Although highly inhibitory murine and human monoclonal antibodies (mAbs) have been generated, the structural basis of their neutralizing activity remains poorly characterized. Here, we determined the cryo-EM structures of chikungunya virus-like particles complexed with antibody fragments (Fab) of two highly protective human mAbs, 4J21 and 5M16, that block virus fusion with host membranes. Both mAbs bind primarily to sites within the A and B domains, as well as to the B domain's β-ribbon connector of the viral glycoprotein E2. The footprints of these antibodies on the viral surface were consistent with results from loss-of-binding studies using an alanine scanning mutagenesis-based epitope mapping approach. The Fab fragments stabilized the position of the B domain relative to the virus, particularly for the complex with 5M16. This finding is consistent with a mechanism of neutralization in which anti-CHIKV mAbs that bridge the A and B domains impede movement of the B domain away from the underlying fusion loop on the E1 glycoprotein and therefore block the requisite pH-dependent fusion of viral and host membranes.
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Affiliation(s)
- Feng Long
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907
| | | | - Stephen K Austin
- Departments of Medicine, Molecular Microbiology, Pathology, and Immunology, Washington University School of Medicine, St. Louis, MO 63110
| | - Zhenguo Chen
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907
| | - Thomas Klose
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907
| | - Andrei Fokine
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907
| | - Yue Liu
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907
| | - Jason Porta
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907
| | - Gopal Sapparapu
- Department of Pediatrics, Vanderbilt University, Nashville, TN 37232
| | | | | | - James E Crowe
- Department of Pediatrics, Vanderbilt University, Nashville, TN 37232; Departments of Pathology, Microbiology, and Immunology, Vanderbilt University, Nashville, TN 37232; Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Vanderbilt University, Nashville, TN 37232
| | - Michael S Diamond
- Departments of Medicine, Molecular Microbiology, Pathology, and Immunology, Washington University School of Medicine, St. Louis, MO 63110
| | - Michael G Rossmann
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907;
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Fox JM, Long F, Edeling MA, Lin H, van Duijl-Richter MKS, Fong RH, Kahle KM, Smit JM, Jin J, Simmons G, Doranz BJ, Crowe JE, Fremont DH, Rossmann MG, Diamond MS. Broadly Neutralizing Alphavirus Antibodies Bind an Epitope on E2 and Inhibit Entry and Egress. Cell 2015; 163:1095-1107. [PMID: 26553503 DOI: 10.1016/j.cell.2015.10.050] [Citation(s) in RCA: 149] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 09/18/2015] [Accepted: 10/19/2015] [Indexed: 01/12/2023]
Abstract
We screened a panel of mouse and human monoclonal antibodies (MAbs) against chikungunya virus and identified several with inhibitory activity against multiple alphaviruses. Passive transfer of broadly neutralizing MAbs protected mice against infection by chikungunya, Mayaro, and O'nyong'nyong alphaviruses. Using alanine-scanning mutagenesis, loss-of-function recombinant proteins and viruses, and multiple functional assays, we determined that broadly neutralizing MAbs block multiple steps in the viral lifecycle, including entry and egress, and bind to a conserved epitope on the B domain of the E2 glycoprotein. A 16 Å resolution cryo-electron microscopy structure of a Fab fragment bound to CHIKV E2 B domain provided an explanation for its neutralizing activity. Binding to the B domain was associated with repositioning of the A domain of E2 that enabled cross-linking of neighboring spikes. Our results suggest that B domain antigenic determinants could be targeted for vaccine or antibody therapeutic development against multiple alphaviruses of global concern.
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Affiliation(s)
- Julie M Fox
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Feng Long
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Melissa A Edeling
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Hueylie Lin
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | | | - Rachel H Fong
- Integral Molecular, Inc., Philadelphia, PA 19104, USA
| | | | - Jolanda M Smit
- University of Groningen and University Medical Center Groningen, 9713 GZ Groningen, the Netherlands
| | - Jing Jin
- Blood Systems Research Institute, San Francisco, CA 94118, USA
| | - Graham Simmons
- Blood Systems Research Institute, San Francisco, CA 94118, USA
| | | | - James E Crowe
- Departments of Pediatrics, Pathology, Microbiology, and Immunology and the Vanderbilt Vaccine Center, Vanderbilt University, Nashville, TN 37235, USA
| | - Daved H Fremont
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Michael G Rossmann
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Michael S Diamond
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA; Center for Human Immunology and Immunotherapy Programs, Washington University School of Medicine, St. Louis, MO 63110, USA.
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40
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Structural Studies of Chikungunya Virus-Like Particles Complexed with Human Antibodies: Neutralization and Cell-to-Cell Transmission. J Virol 2015; 90:1169-77. [PMID: 26537684 DOI: 10.1128/jvi.02364-15] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 10/30/2015] [Indexed: 12/24/2022] Open
Abstract
UNLABELLED Chikungunya virus is a positive-stranded RNA alphavirus. Structures of chikungunya virus-like particles in complex with strongly neutralizing antibody Fab fragments (8B10 and 5F10) were determined using cryo-electron microscopy and X-ray crystallography. By fitting the crystallographically determined structures of these Fab fragments into the cryo-electron density maps, we show that Fab fragments of antibody 8B10 extend radially from the viral surface and block receptor binding on the E2 glycoprotein. In contrast, Fab fragments of antibody 5F10 bind the tip of the E2 B domain and lie tangentially on the viral surface. Fab 5F10 fixes the B domain rigidly to the surface of the virus, blocking exposure of the fusion loop on glycoprotein E1 and therefore preventing the virus from becoming fusogenic. Although Fab 5F10 can neutralize the wild-type virus, it can also bind to a mutant virus without inhibiting fusion or attachment. Although the mutant virus is no longer able to propagate by extracellular budding, it can, however, enter the next cell by traveling through junctional complexes without being intercepted by a neutralizing antibody to the wild-type virus, thus clarifying how cell-to-cell transmission can occur. IMPORTANCE Alphaviral infections are transmitted mainly by mosquitoes. Chikungunya virus (CHIKV), which belongs to the Alphavirus genus, has a wide distribution in the Old World that has expanded in recent years into the Americas. There are currently no vaccines or drugs against alphaviral infections. Therefore, a better understanding of CHIKV and its associated neutralizing antibodies will aid in the development of effective treatments.
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Weger-Lucarelli J, Aliota MT, Kamlangdee A, Osorio JE. Identifying the Role of E2 Domains on Alphavirus Neutralization and Protective Immune Responses. PLoS Negl Trop Dis 2015; 9:e0004163. [PMID: 26473963 PMCID: PMC4608762 DOI: 10.1371/journal.pntd.0004163] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 09/23/2015] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Chikungunya virus (CHIKV) and other alphaviruses are the etiologic agents of numerous diseases in both humans and animals. Despite this, the viral mediators of protective immunity against alphaviruses are poorly understood, highlighted by the lack of a licensed human vaccine for any member of this virus genus. The alphavirus E2, the receptor-binding envelope protein, is considered to be the predominant target of the protective host immune response. Although envelope protein domains have been studied for vaccine and neutralization in flaviviruses, their role in alphaviruses is less characterized. Here, we describe the role of the alphavirus E2 domains in neutralization and protection through the use of chimeric viruses. METHODOLOGY/PRINCIPAL FINDINGS Four chimeric viruses were constructed in which individual E2 domains of CHIKV were replaced with the corresponding domain from Semliki Forest virus (SFV) (ΔDomA/ΔDomB/ΔDomC/ ΔDomA+B). Vaccination studies in mice (both live and inactivated virus) revealed that domain B was the primary determinant of neutralization. Neutralization studies with CHIKV immune serum from humans were consistent with mouse studies, as ΔDomB was poorly neutralized. CONCLUSIONS/SIGNIFICANCE Using chimeric viruses, it was determined that the alphavirus E2 domain B was the critical target of neutralizing antibodies in both mice and humans. Therefore, chimeric viruses may have more relevance for vaccine discovery than peptide-based approaches, which only detect linear epitopes. This study provides new insight into the role of alphavirus E2 domains on neutralization determinants and may be useful for the design of novel therapeutic technologies.
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Affiliation(s)
- James Weger-Lucarelli
- Department of Pathobiological Sciences, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- * E-mail:
| | - Matthew T. Aliota
- Department of Pathobiological Sciences, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Attapon Kamlangdee
- Department of Pathobiological Sciences, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Jorge E. Osorio
- Department of Pathobiological Sciences, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
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Hikke MC, Geertsema C, Wu V, Metz SW, van Lent JW, Vlak JM, Pijlman GP. Alphavirus capsid proteins self-assemble into core-like particles in insect cells: A promising platform for nanoparticle vaccine development. Biotechnol J 2015; 11:266-73. [PMID: 26287127 DOI: 10.1002/biot.201500147] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Revised: 06/18/2015] [Accepted: 08/13/2015] [Indexed: 11/07/2022]
Abstract
The mosquito-borne chikungunya virus (CHIKV) causes arthritic diseases in humans, whereas the aquatic salmonid alphavirus (SAV) is associated with high mortality in aquaculture of salmon and trout. Using modern biotechnological approaches, promising vaccine candidates based upon highly immunogenic, enveloped virus-like particles (eVLPs) have been developed. However, the eVLP structure (core, lipid membrane, surface glycoproteins) is more complex than that of non-enveloped, protein-only VLPs, which are structurally and morphologically 'simple'. In order to develop an alternative to alphavirus eVLPs, in this paper we engineered recombinant baculovirus vectors to produce high levels of alphavirus core-like particles (CLPs) in insect cells by expression of the CHIKV and SAV capsid proteins. The CLPs localize in dense nuclear bodies within the infected cell nucleus and are purified through a rapid and scalable protocol involving cell lysis, sonication and low-speed centrifugation steps. Furthermore, an immunogenic epitope from the alphavirus E2 glycoprotein can be successfully fused to the N-terminus of the capsid protein without disrupting the CLP self-assembling properties. We propose that immunogenic epitope-tagged alphavirus CLPs produced in insect cells present a simple and perhaps more stable alternative to alphavirus eVLPs.
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Affiliation(s)
- Mia C Hikke
- Laboratory of Virology, Wageningen University, Wageningen, The Netherlands
| | - Corinne Geertsema
- Laboratory of Virology, Wageningen University, Wageningen, The Netherlands
| | - Vincen Wu
- Laboratory of Virology, Wageningen University, Wageningen, The Netherlands
| | - Stefan W Metz
- Laboratory of Virology, Wageningen University, Wageningen, The Netherlands
| | - Jan W van Lent
- Laboratory of Virology, Wageningen University, Wageningen, The Netherlands
| | - Just M Vlak
- Laboratory of Virology, Wageningen University, Wageningen, The Netherlands
| | - Gorben P Pijlman
- Laboratory of Virology, Wageningen University, Wageningen, The Netherlands.
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Complete coding sequences of eastern equine encephalitis virus and venezuelan equine encephalitis virus strains isolated from human cases. GENOME ANNOUNCEMENTS 2015; 3:3/2/e00243-15. [PMID: 25908124 PMCID: PMC4408325 DOI: 10.1128/genomea.00243-15] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
We obtained the complete coding genome of an eastern equine encephalitis virus (EEEV) strain, EEEV V105-00210, and the complete genome of a Venezuelan equine encephalitis virus (VEEV) strain, VEEV INH-9813. They were obtained from human cases and are proposed as reference challenge strains for vaccine and therapeutic development in animal models.
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