1
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Zorzan M, Castellan M, Gasparotto M, Dias de Melo G, Zecchin B, Leopardi S, Chen A, Rosato A, Angelini A, Bourhy H, Corti D, Cendron L, De Benedictis P. Antiviral mechanisms of two broad-spectrum monoclonal antibodies for rabies prophylaxis and therapy. Front Immunol 2023; 14:1186063. [PMID: 37638057 PMCID: PMC10449259 DOI: 10.3389/fimmu.2023.1186063] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 07/17/2023] [Indexed: 08/29/2023] Open
Abstract
Rabies is an acute and lethal encephalomyelitis caused by lyssaviruses, among which rabies virus (RABV) is the most prevalent and important for public health. Although preventable through the post-exposure administration of rabies vaccine and immunoglobulins (RIGs), the disease is almost invariably fatal since the onset of clinical signs. Two human neutralizing monoclonal antibodies (mAbs), RVC20 and RVC58, have been shown to be effective in treating symptomatic rabies. To better understand how these mAbs work, we conducted structural modeling and in vitro assays to analyze their mechanisms of action, including their ability to mediate Fc-dependent effector functions. Our results indicate that both RVC20 and RVC58 recognize and lock the RABV-G protein in its pre-fusion conformation. RVC58 was shown to neutralize more potently the extra-cellular virus, while RVC20 mainly acts by reducing viral spreading from infected cells. Importantly, RVC20 was more effective in promoting effector functions compared to RVC58 and 17C7-RAB1 mAbs, the latter of which is approved for human rabies post-exposure treatment. These results provide valuable insights into the multiple mechanisms of action of RVC20 and RVC58 mAbs, offering relevant information for the development of these mAbs as treatment for human rabies.
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Affiliation(s)
- Maira Zorzan
- Laboratory for Emerging Viral Zoonoses, FAO and National Reference Centre for Rabies, Department for Research and Innovation, Istituto Zooprofilattico Sperimentale delle Venezie, Legnaro, Italy
| | - Martina Castellan
- Laboratory for Emerging Viral Zoonoses, FAO and National Reference Centre for Rabies, Department for Research and Innovation, Istituto Zooprofilattico Sperimentale delle Venezie, Legnaro, Italy
| | | | - Guilherme Dias de Melo
- Institut Pasteur, Université Paris Cité, Lyssavirus Epidemiology and Neuropathology Unit, WHO Collaborating Centre for Reference and Research on Rabies, Paris, France
| | - Barbara Zecchin
- Laboratory for Emerging Viral Zoonoses, FAO and National Reference Centre for Rabies, Department for Research and Innovation, Istituto Zooprofilattico Sperimentale delle Venezie, Legnaro, Italy
| | - Stefania Leopardi
- Laboratory for Emerging Viral Zoonoses, FAO and National Reference Centre for Rabies, Department for Research and Innovation, Istituto Zooprofilattico Sperimentale delle Venezie, Legnaro, Italy
| | - Alex Chen
- Vir Biotechnology, San Francisco, CA, United States
| | - Antonio Rosato
- Department of Surgery, Oncology and Gastroenterology, University of Padua, Padua, Italy
- Immunology and Molecular Oncology Diagnostics, Veneto Institute of Oncology, Padua, Italy
| | - Alessandro Angelini
- Department of Molecular Sciences and Nanosystems, Ca’ Foscari University of Venice, Mestre, Italy
- European Centre for Living Technology (ECLT), Venice, Italy
| | - Hervé Bourhy
- Institut Pasteur, Université Paris Cité, Lyssavirus Epidemiology and Neuropathology Unit, WHO Collaborating Centre for Reference and Research on Rabies, Paris, France
| | - Davide Corti
- Humabs BioMed SA, a subsidiary of Vir Biotechnology, Bellinzona, Switzerland
| | - Laura Cendron
- Department of Biology, University of Padua, Padova, Italy
| | - Paola De Benedictis
- Laboratory for Emerging Viral Zoonoses, FAO and National Reference Centre for Rabies, Department for Research and Innovation, Istituto Zooprofilattico Sperimentale delle Venezie, Legnaro, Italy
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2
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Zhu Y. Human Papillomavirus (HPV) Entry Inhibitors. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1366:223-239. [DOI: 10.1007/978-981-16-8702-0_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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3
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Whitehead M, Osborne A, Yu-Wai-Man P, Martin K. Humoral immune responses to AAV gene therapy in the ocular compartment. Biol Rev Camb Philos Soc 2021; 96:1616-1644. [PMID: 33837614 DOI: 10.1111/brv.12718] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 03/25/2021] [Accepted: 03/25/2021] [Indexed: 12/11/2022]
Abstract
Viral vectors can be utilised to deliver therapeutic genes to diseased cells. Adeno-associated virus (AAV) is a commonly used viral vector that is favoured for its ability to infect a wide range of tissues whilst displaying limited toxicity and immunogenicity. Most humans harbour anti-AAV neutralising antibodies (NAbs) due to subclinical infections by wild-type virus during infancy and these pre-existing NAbs can limit the efficiency of gene transfer depending on the target cell type, route of administration and choice of serotype. Vector administration can also result in de novo NAb synthesis that could limit the opportunity for repeated gene transfer to diseased sites. A number of strategies have been described in preclinical models that could circumvent NAb responses in humans, however, the successful translation of these innovations into the clinical arena has been limited. Here, we provide a comprehensive review of the humoral immune response to AAV gene therapy in the ocular compartment. We cover basic AAV biology and clinical application, the role of pre-existing and induced NAbs, and possible approaches to overcoming antibody responses. We conclude with a framework for a comprehensive strategy for circumventing humoral immune responses to AAV in the future.
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Affiliation(s)
- Michael Whitehead
- John Van Geest Centre for Brain Repair, Department of Clinical Neuroscience, University of Cambridge, Cambridge, U.K
| | - Andrew Osborne
- John Van Geest Centre for Brain Repair, Department of Clinical Neuroscience, University of Cambridge, Cambridge, U.K
| | - Patrick Yu-Wai-Man
- John Van Geest Centre for Brain Repair, Department of Clinical Neuroscience, University of Cambridge, Cambridge, U.K.,MRC Mitochondrial Biology Unit, Department of Clinical Neurosciences, University of Cambridge, Cambridge, U.K.,NIHR Biomedical Research Centre at Moorfields Eye Hospital and UCL Institute of Ophthalmology, London, U.K
| | - Keith Martin
- John Van Geest Centre for Brain Repair, Department of Clinical Neuroscience, University of Cambridge, Cambridge, U.K.,Wellcome Trust-MRC Cambridge Stem Cell Institute, University of Cambridge, Cambridge, U.K.,Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, VIC, Australia.,Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, VIC, Australia
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4
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Structural basis for the shared neutralization mechanism of three classes of human papillomavirus type 58 antibodies with disparate modes of binding. J Virol 2021; 95:JVI.01587-20. [PMID: 33472937 PMCID: PMC8092703 DOI: 10.1128/jvi.01587-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Human papillomavirus type 58 (HPV58) is associated with cervical cancer and poses a significant health burden worldwide. Although the commercial 9-valent HPV vaccine covers HPV58, the structural and molecular-level neutralization sites of the HPV58 complete virion are not fully understood. Here, we report the high-resolution (∼3.5 Å) structure of the complete HPV58 pseudovirus (PsV58) using cryo-electron microscopy (cryo-EM). Three representative neutralizing monoclonal antibodies (nAbs 5G9, 2H3 and A4B4) were selected through clustering from a nAb panel against HPV58. Bypassing the steric hindrance and symmetry-mismatch in the HPV Fab-capsid immune-complex, we present three different neutralizing epitopes in the PsV58, and show that, despite differences in binding, these nAbs share a common neutralization mechanism. These results offer insight into HPV58 genotype specificity and broaden our understanding of HPV58 neutralization sites for antiviral research.IMPORTANCE Cervical cancer primarily results from persistent infection with high-risk types of human papillomavirus (HPV). HPV type 58 (HPV58) is an important causative agent, especially within Asia. Despite this, we still have limited data pertaining to the structural and neutralizing epitopes of HPV58, and this encumbers our in-depth understanding of the virus mode of infection. Here, we show that representative nAbs (5G9, 10B11, 2H3, 5H2 and A4B4) from three different groups share a common neutralization mechanism that appears to prohibit the virus from associating with the extracellular matrix and cell surface. Furthermore, we identify that the nAbs engage via three different binding patterns: top-center binding (5G9 and 10B11), top-fringe binding (2H3 and 5H2), and fringe binding (A4B4). Our work shows that, despite differences in the pattern in binding, nAbs against HPV58 share a common neutralization mechanism. These results provide new insight into the understanding of HPV58 infection.
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5
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Zou Z, Liu J, Wang Z, Deng F, Wang H, Hu Z, Wang M, Zhang T. Characterization of two monoclonal antibodies, 38F10 and 44D11, against the major envelope fusion protein of Helicoverpa armigera nucleopolyhedrovirus. Virol Sin 2016; 31:490-499. [PMID: 27995421 DOI: 10.1007/s12250-016-3831-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 11/29/2016] [Indexed: 10/20/2022] Open
Abstract
The envelope fusion protein F of baculoviruses is a class I viral fusion protein which play a significant role during virus entry into insect cells. F is initially synthesized as a precursor (F0) and then cleaved into a disulfide-linked F1 and F2 subunits during the process of protein maturation and secretion. To facilitate further investigation into the structure and function of F protein during virus infection, monoclonal antibodies (mAbs) against the F2 subunit of Helicoverpa armigera nucleopolyhedrovirus (HearNPV) (HaF) were generated. Two kinds of mAbs were obtained according to their different recognition epitopes: one kind of mAbs, as represented by 38F10, recognizes amino acid (aa) 85 to 123 of F2 and the other kind, represented by 44D11, recognizes aa 148 to 173 of F2. Western blot and immunofluorescence assay confirmed that both of the mAbs recognized the F protein expressed in HearNPV infected cells, however, only 44D11 could neutralize HearNPV infection. The results further showed that 44D11 may not interact with a receptor binding epitope, rather it was demonstrated to inhibit syncytium formation in cells expressing the HaF protein. The results imply that the monoclonal antibody 44D11 recognizes a region within HaF2 that may be involved in the F-mediated membrane fusion process.
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Affiliation(s)
- Zijiao Zou
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Jinliang Liu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Zhiying Wang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Fei Deng
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Hualin Wang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Zhihong Hu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Manli Wang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China.
| | - Tao Zhang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China.
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6
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Christensen ND, Budgeon LR, Cladel NM, Hu J. Recent advances in preclinical model systems for papillomaviruses. Virus Res 2016; 231:108-118. [PMID: 27956145 DOI: 10.1016/j.virusres.2016.12.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2016] [Accepted: 12/05/2016] [Indexed: 01/09/2023]
Abstract
Preclinical model systems to study multiple features of the papillomavirus life cycle have greatly aided our understanding of Human Papillomavirus (HPV) biology, disease progression and treatments. The challenge to studying HPV in hosts is that HPV along with most PVs are both species and tissue restricted. Thus, fundamental properties of HPV viral proteins can be assessed in specialized cell culture systems but host responses that involve innate immunity and host restriction factors requires preclinical surrogate models. Fortunately, there are several well-characterized and new animal models of papillomavirus infections that are available to the PV research community. Old models that continue to have value include canine, bovine and rabbit PV models and new rodent models are in place to better assess host-virus interactions. Questions arise as to the strengths and weaknesses of animal PV models for HPV disease and how accurately these preclinical models predict malignant progression, vaccine efficacy and therapeutic control of HPV-associated disease. In this review, we examine current preclinical models and highlight the strengths and weaknesses of the various models as well as provide an update on new opportunities to study the numerous unknowns that persist in the HPV research field.
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Affiliation(s)
- Neil D Christensen
- Department of Pathology and Microbiology and Immunology, Penn State College of Medicine, 500 University Drive, Hershey PA 17033, USA.
| | - Lynn R Budgeon
- Department of Pathology and Microbiology and Immunology, Penn State College of Medicine, 500 University Drive, Hershey PA 17033, USA
| | - Nancy M Cladel
- Department of Pathology and Microbiology and Immunology, Penn State College of Medicine, 500 University Drive, Hershey PA 17033, USA
| | - Jiafen Hu
- Department of Pathology and Microbiology and Immunology, Penn State College of Medicine, 500 University Drive, Hershey PA 17033, USA
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7
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Foss S, Watkinson R, Sandlie I, James LC, Andersen JT. TRIM21: a cytosolic Fc receptor with broad antibody isotype specificity. Immunol Rev 2016; 268:328-39. [PMID: 26497531 PMCID: PMC4670481 DOI: 10.1111/imr.12363] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Antibodies are key molecules in the fight against infections. Although previously thought to mediate protection solely in the extracellular environment, recent research has revealed that antibody-mediated protection extends to the cytosolic compartment of cells. This postentry viral defense mechanism requires binding of the antibody to a cytosolic Fc receptor named tripartite motif containing 21 (TRIM21). In contrast to other Fc receptors, TRIM21 shows remarkably broad isotype specificity as it does not only bind IgG but also IgM and IgA. When viral pathogens coated with these antibody isotypes enter the cytosol, TRIM21 is rapidly recruited and efficient neutralization occurs before the virus has had the time to replicate. In addition, inflammatory signaling is induced. As such, TRIM21 acts as a cytosolic sensor that engages antibodies that have failed to protect against infection in the extracellular environment. Here, we summarize our current understanding of how TRIM21 orchestrates humoral immunity in the cytosolic environment.
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Affiliation(s)
- Stian Foss
- Centre for Immune Regulation (CIR) and Department of Biosciences, University of Oslo, Oslo, Norway.,CIR and Department of Immunology, Oslo University Hospital Rikshospitalet and University of Oslo, Oslo, Norway
| | - Ruth Watkinson
- Protein and Nucleic Acid Chemistry Division, Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
| | - Inger Sandlie
- Centre for Immune Regulation (CIR) and Department of Biosciences, University of Oslo, Oslo, Norway.,CIR and Department of Immunology, Oslo University Hospital Rikshospitalet and University of Oslo, Oslo, Norway
| | - Leo C James
- Protein and Nucleic Acid Chemistry Division, Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
| | - Jan Terje Andersen
- CIR and Department of Immunology, Oslo University Hospital Rikshospitalet and University of Oslo, Oslo, Norway
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8
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Zhang X, Xin L, Li S, Fang M, Zhang J, Xia N, Zhao Q. Lessons learned from successful human vaccines: Delineating key epitopes by dissecting the capsid proteins. Hum Vaccin Immunother 2016; 11:1277-92. [PMID: 25751641 DOI: 10.1080/21645515.2015.1016675] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Recombinant VLP-based vaccines have been successfully used against 3 diseases caused by viral infections: Hepatitis B, cervical cancer and hepatitis E. The VLP approach is attracting increasing attention in vaccine design and development for human and veterinary use. This review summarizes the clinically relevant epitopes on the VLP antigens in successful human vaccines. These virion-like epitopes, which can be delineated with molecular biology, cryo-electron microscopy and x-ray crystallographic methods, are the prerequisites for these efficacious vaccines to elicit functional antibodies. The critical epitopes and key factors influencing these epitopes are discussed for the HEV, HPV and HBV vaccines. A pentamer (for HPV) or a dimer (for HEV and HBV), rather than a monomer, is the basic building block harboring critical epitopes for the assembly of VLP antigen. The processing and formulation of VLP-based vaccines need to be developed to promote the formation and stabilization of these epitopes in the recombinant antigens. Delineating the critical epitopes is essential for antigen design in the early phase of vaccine development and for critical quality attribute analysis in the commercial phase of vaccine manufacturing.
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Affiliation(s)
- Xiao Zhang
- a State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics; National Institute of Diagnostics and Vaccine Development in Infectious Diseases; Xiamen University ; Xiamen , Fujian , PR China
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9
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Zhang X, Li S, Modis Y, Li Z, Zhang J, Xia N, Zhao Q. Functional assessment and structural basis of antibody binding to human papillomavirus capsid. Rev Med Virol 2015; 26:115-28. [PMID: 26676802 DOI: 10.1002/rmv.1867] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 11/19/2015] [Accepted: 11/20/2015] [Indexed: 02/05/2023]
Abstract
Persistent high-risk human papillomavirus (HPV) infection is linked to cervical cancer. Two prophylactic virus-like particle (VLP)-based vaccines have been marketed globally for nearly a decade. Here, we review the HPV pseudovirion (PsV)-based assays for the functional assessment of the HPV neutralizing antibodies and the structural basis for these clinically relevant epitopes. The PsV-based neutralization assay was developed to evaluate the efficacy of neutralization antibodies in sera elicited by vaccination or natural infection or to assess the functional characteristics of monoclonal antibodies. Different antibody binding modes were observed when an antibody was complexed with virions, PsVs or VLPs. The neutralizing epitopes are localized on surface loops of the L1 capsid protein, at various locations on the capsomere. Different neutralization antibodies exert their neutralizing function via different mechanisms. Some antibodies neutralize the virions by inducing conformational changes in the viral capsid, which can result in concealing the binding site for a cellular receptor like 1A1D-2 against dengue virus, or inducing premature genome release like E18 against enterovirus 71. Higher-resolution details on the epitope composition of HPV neutralizing antibodies would shed light on the structural basis of the highly efficacious vaccines and aid the design of next generation vaccines. In-depth understanding of epitope composition would ensure the development of function-indicating assays for the comparability exercise to support process improvement or process scale up. Elucidation of the structural elements of the type-specific epitopes would enable rational design of cross-type neutralization via epitope re-engineering or epitope grafting in hybrid VLPs.
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Affiliation(s)
- Xiao Zhang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Institute of Diagnostics and Vaccine Development in Infectious Diseases, Xiamen University, Xiamen, Fujian, China.,School of Public Health, Xiamen University, Xiamen, Fujian, China
| | - Shaowei Li
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Institute of Diagnostics and Vaccine Development in Infectious Diseases, Xiamen University, Xiamen, Fujian, China.,School of Public Health, Xiamen University, Xiamen, Fujian, China.,School of Life Science, Xiamen University, Xiamen, Fujian, China
| | - Yorgo Modis
- Department of Medicine, University of Cambridge, MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Zhihai Li
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Institute of Diagnostics and Vaccine Development in Infectious Diseases, Xiamen University, Xiamen, Fujian, China.,School of Life Science, Xiamen University, Xiamen, Fujian, China
| | - Jun Zhang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Institute of Diagnostics and Vaccine Development in Infectious Diseases, Xiamen University, Xiamen, Fujian, China.,School of Public Health, Xiamen University, Xiamen, Fujian, China
| | - Ningshao Xia
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Institute of Diagnostics and Vaccine Development in Infectious Diseases, Xiamen University, Xiamen, Fujian, China.,School of Public Health, Xiamen University, Xiamen, Fujian, China.,School of Life Science, Xiamen University, Xiamen, Fujian, China
| | - Qinjian Zhao
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Institute of Diagnostics and Vaccine Development in Infectious Diseases, Xiamen University, Xiamen, Fujian, China.,School of Public Health, Xiamen University, Xiamen, Fujian, China
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10
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Xiao Y, Wang J, Ma L, Ren J, Yang M. Nucleotide and phylogenetic analysis of human papillomavirus type 11 isolated from juvenile-onset recurrent respiratory papillomatosis in China. J Med Virol 2015; 88:686-94. [PMID: 26369639 DOI: 10.1002/jmv.24381] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/14/2015] [Indexed: 11/07/2022]
Affiliation(s)
- Yang Xiao
- Key Laboratory of Otolaryngology Head and Neck Surgery (Ministry of Education of China); Department of Otolaryngology Head and Neck Surgery; Beijing Tongren Hospital; Capital Medical University; Beijing China
| | - Jun Wang
- Key Laboratory of Otolaryngology Head and Neck Surgery (Ministry of Education of China); Department of Otolaryngology Head and Neck Surgery; Beijing Tongren Hospital; Capital Medical University; Beijing China
| | - Lijing Ma
- Key Laboratory of Otolaryngology Head and Neck Surgery (Ministry of Education of China); Department of Otolaryngology Head and Neck Surgery; Beijing Tongren Hospital; Capital Medical University; Beijing China
| | - Jiaming Ren
- Key Laboratory of Otolaryngology Head and Neck Surgery (Ministry of Education of China); Department of Otolaryngology Head and Neck Surgery; Beijing Tongren Hospital; Capital Medical University; Beijing China
| | - Molei Yang
- Key Laboratory of Otolaryngology Head and Neck Surgery (Ministry of Education of China); Department of Otolaryngology Head and Neck Surgery; Beijing Tongren Hospital; Capital Medical University; Beijing China
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11
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A cryo-electron microscopy study identifies the complete H16.V5 epitope and reveals global conformational changes initiated by binding of the neutralizing antibody fragment. J Virol 2014; 89:1428-38. [PMID: 25392224 DOI: 10.1128/jvi.02898-14] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
UNLABELLED Human papillomavirus 16 (HPV16) is a worldwide health threat and an etiologic agent of cervical cancer. To understand the antigenic properties of HPV16, we pursued a structural study to elucidate HPV capsids and antibody interactions. The cryo-electron microscopy (cryo-EM) structures of a mature HPV16 particle and an altered capsid particle were solved individually and as complexes with fragment of antibody (Fab) from the neutralizing antibody H16.V5. Fitted crystal structures provided a pseudoatomic model of the virus-Fab complex, which identified a precise footprint of H16.V5, including previously unrecognized residues. The altered-capsid-Fab complex map showed that binding of the Fab induced significant conformational changes that were not seen in the altered-capsid structure alone. These changes included more ordered surface loops, consolidated so-called "invading-arm" structures, and tighter intercapsomeric connections at the capsid floor. The H16.V5 Fab preferentially bound hexavalent capsomers likely with a stabilizing effect that directly correlated with the number of bound Fabs. Additional cryo-EM reconstructions of the virus-Fab complex for different incubation times and structural analysis provide a model for a hyperstabilization of the capsomer by H16.V5 Fab and showed that the Fab distinguishes subtle differences between antigenic sites. IMPORTANCE Our analysis of the cryo-EM reconstructions of the HPV16 capsids and virus-Fab complexes has identified the entire HPV.V5 conformational epitope and demonstrated a detailed neutralization mechanism of this clinically important monoclonal antibody against HPV16. The Fab bound and ordered the apical loops of HPV16. This conformational change was transmitted to the lower region of the capsomer, resulting in enhanced intercapsomeric interactions evidenced by the more ordered capsid floor and "invading-arm" structures. This study advances the understanding of the neutralization mechanism used by H16.V5.
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12
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Abstract
ABSTRACT
Antibodies can impact pathogens in the presence or in the absence of effector cells or effector molecules such as complement, and experiments can often sort out with precision the mechanisms by which an antibody inhibits a pathogen
in vitro
. In addition,
in vivo
models, particularly those engineered to knock in or knock out effector cells or effector molecules, are excellent tools for understanding antibody functions. However, it is highly likely that multiple antibody functions occur simultaneously or sequentially in the presence of an infecting organism
in vivo
. The most critical incentive for measuring antibody functions is to provide a basis for vaccine development and for the development of therapeutic antibodies. In this respect, some functions, such as virus neutralization, serve to inhibit the acquisition of a pathogen or limit its pathogenesis. However, antibodies can also enhance replication or contribute to pathogenesis. This review emphasizes those antibody functions that are potentially beneficial to the host. In addition, this review will focus on the effects of antibodies on organisms themselves, rather than on the toxins the organisms may produce.
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13
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Zhao Q, Potter CS, Carragher B, Lander G, Sworen J, Towne V, Abraham D, Duncan P, Washabaugh MW, Sitrin RD. Characterization of virus-like particles in GARDASIL® by cryo transmission electron microscopy. Hum Vaccin Immunother 2013; 10:734-9. [PMID: 24299977 DOI: 10.4161/hv.27316] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Cryo-transmission electron microscopy (cryoTEM) is a powerful characterization method for assessing the structural properties of biopharmaceutical nanoparticles, including Virus Like Particle-based vaccines. We demonstrate the method using the Human Papilloma Virus (HPV) VLPs in GARDASIL®. CryoTEM, coupled to automated data collection and analysis, was used to acquire images of the particles in their hydrated state, determine their morphological characteristics, and confirm the integrity of the particles when absorbed to aluminum adjuvant. In addition, we determined the three-dimensional structure of the VLPs, both alone and when interacting with neutralizing antibodies. Two modes of binding of two different neutralizing antibodies were apparent; for HPV type 11 saturated with H11.B2, 72 potential Fab binding sites were observed at the center of each capsomer, whereas for HPV 16 interacting with H16.V5, it appears that 60 pentamers (each neighboring 6 other pentamers) bind five Fabs per pentamer, for the total of 300 potential Fab binding sites per VLP.
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Affiliation(s)
- Qinjian Zhao
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics; School of Public Health; Xiamen University; Xiamen, Fujian, PR China; Bioprocess R&D; Merck Research Laboratories; West Point, PA USA
| | - Clinton S Potter
- NanoImaging Services, Inc.; San Diego, CA USA; Department of Integrative Structural and Computational Biology; The Scripps Research Institute; La Jolla, CA USA
| | - Bridget Carragher
- NanoImaging Services, Inc.; San Diego, CA USA; Department of Integrative Structural and Computational Biology; The Scripps Research Institute; La Jolla, CA USA
| | - Gabriel Lander
- Department of Integrative Structural and Computational Biology; The Scripps Research Institute; La Jolla, CA USA
| | - Jaime Sworen
- Bioprocess R&D; Merck Research Laboratories; West Point, PA USA
| | - Victoria Towne
- Vaccine Manufacturing Science and Commercialization; Merck Manufacturing Division; West Point, PA USA
| | - Dicky Abraham
- Vaccine Manufacturing Science and Commercialization; Merck Manufacturing Division; West Point, PA USA
| | - Paul Duncan
- Bioprocess R&D; Merck Research Laboratories; West Point, PA USA
| | | | - Robert D Sitrin
- Vaccine Manufacturing Science and Commercialization; Merck Manufacturing Division; West Point, PA USA
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14
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Differential accessibility of a rotavirus VP6 epitope in trimers comprising type I, II, or III channels as revealed by binding of a human rotavirus VP6-specific antibody. J Virol 2013; 88:469-76. [PMID: 24155406 DOI: 10.1128/jvi.01665-13] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Previous human antibody studies have shown that the human VH1-46 antibody variable gene segment encodes much of the naturally occurring human B cell response to rotavirus and is directed to virus protein 6 (VP6). It is currently unknown why some of the VH1-46-encoded human VP6 monoclonal antibodies inhibit viral transcription while others do not. In part, there are affinity differences between antibodies that likely affect inhibitory activity, but we also hypothesize that there are differing modes of binding to VP6 that affect the ability to block the transcriptional pore on double-layered particles. Here, we used a hybrid method approach for antibody epitope mapping, including single-particle cryo-electron microscopy (cryo-EM) and enhanced amide hydrogen-deuterium exchange mass spectrometry (DXMS) to determine the location and mode of binding of a VH1-46-encoded antibody, RV6-25. The structure of the RV6-25 antibody-double-layered particle (DLP) complex indicated a very complex binding pattern that revealed subtle differences in accessibility of the VP6 epitope depending on its position in the type I, II, or III channels. These subtle variations in the presentation or accessibility of the RV VP6 capsid layer led to position-specific differences in occupancy for binding of the RV6-25 antibody. The studies also showed that the location of binding of the noninhibitory antibody RV6-25 on the apical surface of RV VP6 head domain does not obstruct the transcription pore upon antibody binding, in contrast to binding of an inhibitory antibody, RV6-26, deeper in the transcriptional pore.
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15
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Selinka HC, Sapp M. Papillomavirus/cell-interactions initiating the infectious entry pathway. ACTA ACUST UNITED AC 2013. [DOI: 10.1179/095741903225003235] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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16
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Towne V, Zhao Q, Brown M, Finnefrock AC. Pairwise antibody footprinting using surface plasmon resonance technology to characterize human papillomavirus type 16 virus-like particles with direct anti-HPV antibody immobilization. J Immunol Methods 2012; 388:1-7. [PMID: 23159495 DOI: 10.1016/j.jim.2012.11.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Revised: 10/28/2012] [Accepted: 11/08/2012] [Indexed: 10/27/2022]
Abstract
This paper describes an approach to surface plasmon resonance (SPR) based epitope mapping, also referred to as pairwise antibody footprinting, involving the direct immobilization of an antigen-specific primary mAb to the surface of an SPR interface. This technique offers a more straightforward approach than indirect capture (e.g., via rabbit anti-mouse Fc) as it does not require additional steps to block the unoccupied immobilized anti-Fc to prevent non-specific antibody binding. This is also an alternative to the direct immobilization of an antigen of interest, which may cause conformational changes in the antigen or epitope degradation upon chemical immobilization, particularly in successive regeneration cycles. It is particularly suitable for highly multivalent targets such as virus-like particles (VLPs). Using this technique, we assessed a panel of eight monoclonal antibodies against HPV (human papilloma virus) L1 protein VLPs expressed by Saccharomyces cerevisiae. In the antibody epitope screening studies, HPV16 L1-directed conformational mAbs were clearly distinguished from the linear mAbs and consistent with known epitope information. Additional studies using a linear mAb and a conformational mAb demonstrate the practical application of this technique for characterizing the result of process changes and the consistency of recombinant HPV16 VLPs. The method is readily extensible to other VLPs and VLP-based vaccines.
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Affiliation(s)
- Victoria Towne
- Vaccine Manufacturing Sciences and Commercialization, Merck Research Laboratories, West Point, PA 19486, USA
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17
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Abstract
Despite a central role in immunity, antibody neutralization of virus infection is poorly understood. Here we show how the neutralization and persistence of adenovirus type 5, a prevalent nonenveloped human virus, are dependent upon the intracellular antibody receptor TRIM21. Cells with insufficient amounts of TRIM21 are readily infected, even at saturating concentrations of neutralizing antibody. Conversely, high TRIM21 expression levels decrease the persistent fraction of the infecting virus and allows neutralization by as few as 1.6 antibody molecules per virus. The direct interaction between TRIM21 and neutralizing antibody is essential, as single-point mutations within the TRIM21-binding site in the Fc region of a potently neutralizing antibody impair neutralization. However, infection at high multiplicity can saturate TRIM21 and overcome neutralization. These results provide insight into the mechanism and importance of a newly discovered, effector-driven process of antibody neutralization of nonenveloped viruses.
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18
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Brandt S, Tober R, Corteggio A, Burger S, Sabitzer S, Walter I, Kainzbauer C, Steinborn R, Nasir L, Borzacchiello G. BPV-1 infection is not confined to the dermis but also involves the epidermis of equine sarcoids. Vet Microbiol 2011; 150:35-40. [DOI: 10.1016/j.vetmic.2010.12.021] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2010] [Revised: 12/07/2010] [Accepted: 12/14/2010] [Indexed: 10/18/2022]
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19
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Dowd KA, Pierson TC. Antibody-mediated neutralization of flaviviruses: a reductionist view. Virology 2011; 411:306-15. [PMID: 21255816 PMCID: PMC3100196 DOI: 10.1016/j.virol.2010.12.020] [Citation(s) in RCA: 141] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2010] [Accepted: 12/11/2010] [Indexed: 12/28/2022]
Abstract
Flaviviruses are a group of ~70 small RNA viruses responsible for significant morbidity and mortality across the globe. Efforts to develop effective vaccines for several clinically important flaviviruses are underway. Antibodies are a significant component of the host's protective response against flavivirus infection with the potential to contribute to immunity via several distinct mechanisms, including an ability to directly neutralize virus infection. Conversely, virus-reactive antibodies have been implicated in the increased risk of severe clinical manifestations following secondary dengue virus infection. In this review, we will discuss recent progress toward understanding the molecular basis of antibody-mediated neutralization of flaviviruses. Neutralization requires engagement of the virion with a stoichiometry that exceeds a required threshold. From this perspective, we will discuss viral and host factors that impact the number of antibody molecules bound to the virus particle and significantly modulate the potency of neutralizing antibodies.
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Affiliation(s)
- Kimberly A. Dowd
- Viral Pathogenesis Section, Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Theodore C. Pierson
- Viral Pathogenesis Section, Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
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20
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Abstract
Vaccines against the human papillomaviruses (HPVs) most frequently associated with cancer of the cervix are now available. These prophylactic vaccines, based on virus-like particles (VLPs), are extremely effective, providing protection from infection in almost 100% of cases. However, the vaccines present some limitations: they are effective primarily against the HPV type present in the vaccine, are expensive to produce, and need a cold chain. Vaccines based on the minor capsid protein L2 have been very successful in animal models and have been shown to provide a good level of protection against different papillomavirus types. The potential of L2-based vaccines to protect against many types of HPVs is discussed.
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21
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Developing vaccines against minor capsid antigen L2 to prevent papillomavirus infection. Immunol Cell Biol 2009; 87:287-99. [PMID: 19421199 DOI: 10.1038/icb.2009.13] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A subset of human papillomavirus (HPV) genotypes is responsible for approximately 5% of all cancer deaths globally, and uterine cervical carcinoma accounts for the majority of these cases. The impact of HPV is greatest for women who do not have access to effective secondary preventive measures, and consequently over 80% of cervical cancer deaths worldwide occur in developing nations. The understanding that persistent infection by this 'oncogenic' subset of HPV genotypes is necessary for the development of cervical carcinoma has driven the development of preventive vaccines. Two preventive vaccines comprising recombinant HPV L1 virus-like particles (VLPs) have been licensed. However, the current cost of these vaccines precludes sustained global delivery, and they target only two of the approximately 15 known oncogenic HPV types, although approximately 70% of cervical cancer cases are attributed to these two types and there is evidence for some degree of cross-protection against other closely related types. A possible approach to broader immunity at lower cost is to consider vaccination against L2. L2 vaccines can be produced inexpensively and they also have the promise of conferring much broader cross-type protective immunity than that observed with L1 VLP immunization. However, L2 vaccine development lags behind L1 VLP vaccines and several technical hurdles remain.
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22
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Hepburn HM, Kaufmann AM. [Nobel price for vaccination against cervical cancer: current data and guidelines]. Internist (Berl) 2009; 50:617-26. [PMID: 19384543 DOI: 10.1007/s00108-009-2388-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Harald zur Hausen received the Nobel price for Medicine in 2008 for his seminal research on human papilloma viruses and their association with anogenital diseases. On the basis of his work highly effective prophylactic vaccines have been developed. Clinical studies have shown nearly 100% seroconversion and an excellent safety profile as well as greater than 96% efficacy against HPV infection and premalignant dysplasia, induced by HPV types covered by the vaccine. Due to the convincing data of phase II and III clinical trials the introduction of HPV vaccination was recommended by health authorities and scientific committees in Germany. The development and availability of guidelines and evidence-based recommendations should support the introduction of the vaccine and widespread vaccination.
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Affiliation(s)
- H M Hepburn
- Gynäkologische Tumorimmunologie, Klinik für Gynäkologie, Charité, Campus Benjamin Franklin, Berlin
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23
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Lopez TV, Cancio C, Cruz-Talonia F, Ruiz B, Sapp M, Rocha-Zavaleta L. Binding of human papillomavirus type 16 to heparan sulfate is inhibited by mucosal antibodies from patients with low-grade squamous intraepithelial lesions but not from cervical cancer patients. ACTA ACUST UNITED AC 2009; 54:167-76. [PMID: 19049640 DOI: 10.1111/j.1574-695x.2008.00484.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Mucosal antibodies against human papillomavirus type 16 (HPV16) capsids have been detected in infected women. To determine whether these antibodies recognize and block the receptor site mediating attachment of HPV16 to heparan sulfate, mucus samples from 126 HPV16-associated low-grade squamous intraepithelial lesion (LSIL) and 85 cervical cancer patients, previously found to react to HPV16 virus-like particles (VLP), and 101 normal controls were tested in an inhibition assay, using HPV16 VLP and heparan sulfate proteoglycan-coated plates. Inhibition levels of 9.3-67.2% were mediated by type-specific antibodies in 94.4% of LSIL patients. Cervical cancer cases showed significantly lower levels of inhibition than LSIL samples (P < 0.0001). The potential of antibodies to inhibit infection was explored in a pseudoinfection system using HPV16 pseudovirions. Inhibition of pseudoinfection by LSIL samples was significantly higher than that observed in the controls (P < 0.001) and cervical cancer cases (P < 0.005). These results indicate that mucosal antibodies inhibiting binding of VLP to heparan sulfate are developed in most LSIL patients, but are hardly present in cervical cancer patients.
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Affiliation(s)
- Tania V Lopez
- Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México
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24
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Knappe M, Bodevin S, Selinka HC, Spillmann D, Streeck RE, Chen XS, Lindahl U, Sapp M. Surface-exposed Amino Acid Residues of HPV16 L1 Protein Mediating Interaction with Cell Surface Heparan Sulfate. J Biol Chem 2007; 282:27913-22. [PMID: 17640876 DOI: 10.1074/jbc.m705127200] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Efficient infection of cells by human papillomaviruses (HPVs) and pseudovirions requires primary interaction with cell surface proteoglycans with apparent preference for species carrying heparan sulfate (HS) side chains. To identify residues contributing to virus/cell interaction, we performed point mutational analysis of the HPV16 major capsid protein, L1, targeting surface-exposed amino acid residues. Replacement of lysine residues 278, 356, or 361 for alanine reduced cell binding and infectivity of pseudovirions. Various combinations of these amino acid exchanges further decreased cell attachment and infectivity with residual infectivity of less than 5% for the triple mutant, suggesting that these lysine residues cooperate in HS binding. Single, double, or triple exchanges for arginine did not impair infectivity, demonstrating that interaction is dependent on charge distribution rather than sequence-specific. The lysine residues are located within a pocket on the capsomere surface, which was previously proposed as the putative receptor binding site. Fab fragments of binding-neutralizing antibody H16.56E that recognize an epitope directly adjacent to lysine residues strongly reduced HS-mediated cell binding, further corroborating our findings. In contrast, mutation of basic surface residues located in the cleft between capsomeres outside this pocket did not significantly reduce interaction with HS or resulted in assembly-deficient proteins. Computer-simulated heparin docking suggested that all three lysine residues can form hydrogen bonds with 2-O-, 6-O-, and N-sulfate groups of a single HS molecule with a minimal saccharide domain length of eight monomer units. This prediction was experimentally confirmed in binding experiments using capsid protein, heparin molecules of defined length, and sulfate group modifications.
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Affiliation(s)
- Maren Knappe
- Institute for Medical Microbiology, University of Mainz, D-55101 Mainz, Germany
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25
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Gromowski GD, Barrett ADT. Characterization of an antigenic site that contains a dominant, type-specific neutralization determinant on the envelope protein domain III (ED3) of dengue 2 virus. Virology 2007; 366:349-60. [PMID: 17719070 DOI: 10.1016/j.virol.2007.05.042] [Citation(s) in RCA: 153] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2007] [Revised: 03/22/2007] [Accepted: 05/22/2007] [Indexed: 11/27/2022]
Abstract
The surface of the mature dengue virus (DENV) particle consists of 90 envelope (E) protein dimers that mediate both receptor binding and fusion. The E protein ectodomain can be divided into three structural domains designated ED1, ED2, and ED3, of which ED3 contains the critical and dominant virus-specific neutralization sites. In this study the ED3 epitopes recognized by seven, murine, IgG1 DENV-2 type-specific, monoclonal antibodies (MAbs) were determined using site-directed mutagenesis of a recombinant DENV-2 ED3 (rED3) protein. A total of 41 single amino acid substitutions were introduced into the rED3 at 30 different surface accessible residues. The affinity of each MAb with the mutant rED3s was assessed by indirect ELISA and the results indicate that all seven MAbs recognize overlapping epitopes with residues K305 and P384 critical for binding. These residues are conserved among DENV-2 strains and cluster together on the upper lateral face of ED3. A linear relationship was observed between relative occupancy of ED3 on the virion by MAb and neutralization of the majority of virus infectivity ( approximately 90%) for all seven MAbs. Depending on the MAb, it is predicted that between 10% and 50% relative occupancy of ED3 on the virion is necessary for virus neutralization and for all seven MAbs occupancy levels approaching saturation were required for 100% neutralization of virus infectivity. Overall, the conserved antigenic site recognized by all seven MAbs is likely to be a dominant DENV-2 type-specific, neutralization determinant.
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MESH Headings
- Amino Acid Sequence
- Amino Acid Substitution/genetics
- Amino Acid Substitution/immunology
- Antibodies, Monoclonal/immunology
- Antibodies, Viral/immunology
- Antibody Affinity
- Antigens, Viral/chemistry
- Antigens, Viral/genetics
- Antigens, Viral/immunology
- Dengue Virus/immunology
- Enzyme-Linked Immunosorbent Assay
- Epitope Mapping
- Epitopes, B-Lymphocyte/genetics
- Epitopes, B-Lymphocyte/immunology
- Immunodominant Epitopes/genetics
- Immunodominant Epitopes/immunology
- Immunoglobulin G/immunology
- Models, Molecular
- Molecular Sequence Data
- Mutagenesis, Site-Directed
- Neutralization Tests
- Protein Structure, Tertiary/genetics
- Viral Envelope Proteins/chemistry
- Viral Envelope Proteins/genetics
- Viral Envelope Proteins/immunology
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Affiliation(s)
- Gregory D Gromowski
- Department of Pathology, Sealy Center for Vaccine Development, Center for Biodefense and Emerging Infectious Diseases, and Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX 77555-0609, USA
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26
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Day PM, Thompson CD, Buck CB, Pang YYS, Lowy DR, Schiller JT. Neutralization of human papillomavirus with monoclonal antibodies reveals different mechanisms of inhibition. J Virol 2007; 81:8784-92. [PMID: 17553881 PMCID: PMC1951340 DOI: 10.1128/jvi.00552-07] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The mechanisms of human papillomavirus (HPV) neutralization by antibodies are incompletely understood. We have used HPV16 pseudovirus infection of HaCaT cells to analyze how several neutralizing monoclonal antibodies (MAbs) generated against HPV16 L1 interfere with the process of keratinocyte infection. HPV16 capsids normally bind to both the cell surface and extracellular matrix (ECM) of HaCaT cells. Surprisingly, two strongly neutralizing MAbs, V5 and E70, did not prevent attachment of capsids to the cell surface. However, they did block association with the ECM and prevented internalization of cell surface-bound capsids. In contrast, MAb U4 prevented binding to the cell surface but not to the ECM. The epitope recognized by U4 was inaccessible when virions were bound to the cell surface but became accessible after endocytosis, presumably coinciding with receptor detachment. Treatment of capsids with heparin, which is known to interfere with binding to cell surface heparan sulfate proteoglycans (HSPGs), also resulted in HPV16 localization to the ECM. These results suggest that the U4 epitope on the intercapsomeric C-terminal arm is likely to encompass the critical HSPG interaction residues for HPV16, while the V5 and E70 epitopes at the apex of the capsomer overlap the ECM-binding sites. We conclude that neutralizing antibodies can inhibit HPV infection by multiple distinct mechanisms, and understanding these mechanisms can add insight to the HPV entry processes.
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Affiliation(s)
- Patricia M Day
- Laboratory of Cellular Oncology, Center for Cancer Research, National Institutes of Health, Bethesda, MD 20892, USA.
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27
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Abstract
Human papillomaviruses (HPV) infect skin or mucosal epithelia causing warts and dysplasia. Infections with certain high-risk HPV types in the anogenital tract can lead to malignant transformation. Cervical cancer is the second most common malignant disease in young women responsible for 275000 deaths annually worldwide. More than 50% of sexually active people acquire HPV infections over their lifetime. Around 80% of infections remain subclinical and are cleared by the immune system. Recently prophylactic vaccines against the two most common high-risk types HPV16 and 18, and additionally low-risk types HPV6 and 11, respectively, have become available. We present an overview concerning recent knowledge on natural and vaccine-induced immunity against HPV infections.
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Affiliation(s)
- E Glastetter
- Gynäkologische Tumorimmunologie, Klinik für Gynäkologie, Charité Campus Benjamin Franklin, Hindenburgdamm 30, 12200 Berlin, Deutschland.
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28
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Studentsov YY, Burk RD. Development of a non-denaturing electrophoresis system for characterization of neutralizing epitopes on HPV virus-like particles. J Virol Methods 2007; 139:208-19. [PMID: 17137641 DOI: 10.1016/j.jviromet.2006.10.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2006] [Revised: 09/29/2006] [Accepted: 10/19/2006] [Indexed: 10/23/2022]
Abstract
The precise structure of the HPV16 major neutralizing epitope recognized by H16.V5 monoclonal antibody is unknown. This paper describes a novel polyacrylamide gel electrophoresis (PAGE) for separation of HPV virus-like particles (VLPs) using cetyltrimethylammonium chloride (CTAC) as a solubilizing agent. CTAC PAGE employs KOH/CH3CO2H (pH 4-5.4) as a buffer system, K+ as the leading ion and 3-aminopropionic acid as a trailing ion. The unique characteristics of a cationic electrophoresis system allow separation of VLPs without heat denaturation. HPV VLP gel migration patterns were dependent on pre-treatment conditions: (1) thiol-agent reduction alone resulted in a 174 kDa band (interpreted as a L1 trimer), a 53 kDa band (size of the L1 monomer), as well as higher Mr aggregates consistent with a pentamer size; (2) both heat denaturation and thiol-agent reduction resulted in a 53 kDa band. Western blot analysis showed that the 174 kDa L1 trimer was strongly immunoreactive with H16.V5 and HPV16 VLP ELISA positive human sera, whereas no reactivity was seen with the monomeric L1 unit. These data suggest that a structure consistent with the migration pattern of a L1 trimer contains the major neutralizing epitope recognized by the H16.V5 MAb and human sera.
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Affiliation(s)
- Yevgeniy Y Studentsov
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Ullmann Bldg., Rm. 519, Bronx, NY 10461, USA.
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29
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Culp TD, Spatz CM, Reed CA, Christensen ND. Binding and neutralization efficiencies of monoclonal antibodies, Fab fragments, and scFv specific for L1 epitopes on the capsid of infectious HPV particles. Virology 2007; 361:435-46. [PMID: 17222883 PMCID: PMC2040078 DOI: 10.1016/j.virol.2006.12.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2006] [Revised: 11/03/2006] [Accepted: 12/04/2006] [Indexed: 11/20/2022]
Abstract
We compared the neutralization abilities of individual monoclonal antibodies (MAb) of two large panels reactive with L1 epitopes of HPV-11 or HPV-16. Binding titers were compared using both L1-only VLPs and L1/L2 pseudovirions. While the VLPs were antigenically similar to the pseudovirions, clear differences in the surface exposure of some epitopes were evident with the HPV-16 particles. To determine whether all antibody binding events are equivalent in their neutralizing effect on infectious HPV virions or pseudovirions, the binding and neutralization titers for individual MAbs were used to calculate the relative neutralization efficiency for each antibody. HPV neutralization was achieved by all MAbs capable of strong binding to either linear or conformation-sensitive epitopes on pseudovirus particles. Our data suggest, however, that some L1 epitopes may be more neutralization-sensitive than other surface epitopes, in that successful infection can be blocked by varying degrees of epitope saturation. Additionally, the effective neutralization of virions by several monovalent Fab fragments and single-chain variable fragments (scFv) demonstrates that viral neutralization does not require HPV particle aggregation or L1 crosslinking. Identification of capsid protein structures rich in neutralization-sensitive epitopes may aid in the development of improved recombinant vaccines capable of eliciting effective and long-term antibody-mediated protection against multiple HPV types.
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Affiliation(s)
- Timothy D Culp
- Gittlen Cancer Research Foundation, Pennsylvania State University, Hershey, PA 17033, USA
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30
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Greig SL, Berriman JA, O'Brien JA, Taylor JA, Bellamy AR, Yeager MJ, Mitra AK. Structural determinants of rotavirus subgroup specificity mapped by cryo-electron microscopy. J Mol Biol 2005; 356:209-21. [PMID: 16359700 DOI: 10.1016/j.jmb.2005.11.049] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2005] [Revised: 11/10/2005] [Accepted: 11/15/2005] [Indexed: 11/30/2022]
Abstract
The rotavirus double-layered particle (DLP) is a molecular machine that transcribes 11 genomic segments of double-stranded RNA into full-length mRNA segments during viral replication. DLPs from the human Wa strain of virus, belonging to subgroup II (SG II), possess a significantly reduced level of transcriptase activity compared to bovine UK DLPs that belong to subgroup I (SG I). Cryo-electron microscopy and icosahedral image analysis was used to define the structural basis for this difference in transcriptase activity and to derive three-dimensional density maps of bovine UK and human Wa DLPs at 26 angstroms and 28 angstroms resolution, respectively. The two rotavirus strains had the same diameter, T = 13 l icosahedral lattice symmetry and size of the VP6 trimers on the surface of the DLPs. However, the Wa particles displayed a remarkable absence of VP6 trimers surrounding each 5-fold vertex position. To further explore these structural differences, three-dimensional reconstructions were generated of DLPs decorated with Fab fragments derived from subgroup-specific monoclonal antibodies. The X-ray structures of VP6 and a generic Fab fragment were then docked into the cryo-electron microscopy density maps, which allowed us to propose at "pseudo-atomic" resolution the locations of the amino acid residues defining the subgroup-specific epitopes. Our results demonstrate a correlation between the structure of the VP6 layer and the transcriptase activity of the particles, and suggest that the stability of VP6 trimers, specifically those at the icosahedral 5-fold axes, may be critical for mRNA synthesis. Thus, subgroup specificity of rotavirus may reflect differences in the architecture of the double-layered particle, with resultant consequences for viral mRNA synthesis.
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Affiliation(s)
- Sarah L Greig
- School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
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31
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Harris A, Belnap DM, Watts NR, Conway JF, Cheng N, Stahl SJ, Vethanayagam JG, Wingfield PT, Steven AC. Epitope diversity of hepatitis B virus capsids: quasi-equivalent variations in spike epitopes and binding of different antibodies to the same epitope. J Mol Biol 2005; 355:562-76. [PMID: 16309704 DOI: 10.1016/j.jmb.2005.10.035] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2005] [Revised: 09/28/2005] [Accepted: 10/11/2005] [Indexed: 12/21/2022]
Abstract
To investigate the range of antigenic variation of HBV capsids, we have characterized the epitopes for two anti-capsid antibodies by cryo-electron microscopy and image reconstruction of Fab-labeled capsids to approximately 10A resolution followed by molecular modeling. Both antibodies engage residues on the protruding spikes but their epitopes and binding orientations differ. Steric interference effects limit maximum binding to approximately 50% average occupancy in each case. However, the occupancies of the two copies of a given epitope that are present on a single spike differ, reflecting subtle distinctions in structure and hence, binding affinity, arising from quasi-equivalence. The epitope for mAb88 is conformational but continuous, consisting of a loop-helix motif (residues 77-87) on one of the two polypeptide chains in the spike. In contrast, the epitope for mAb842, like most conformational epitopes, is discontinuous, consisting of a loop on one polypeptide chain (residues 74-78) combined with a loop-helix element (residues 78-83) on the other. The epitope of mAb842 is essentially identical with that previously mapped for mAb F11A4, although the binding orientations of the two monoclonal antibodies (mAbs) differ, as do their affinities measured by surface plasmon resonance. From the number of monoclonals (six) whose binding had to be characterized to give the first duplicate epitope, we estimate the total number of core antigen (cAg) epitopes to be of the order of 20. Given that different antibodies may share the same epitope, the potential number of distinct anti-cAg clones should be considerably higher. The observation that the large majority of cAg epitopes are conformational reflects the relative dimensions of a Fab (large) and the small size and close packing of the motifs that are exposed and accessible on the capsid surface.
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Affiliation(s)
- A Harris
- Laboratory of Structural Biology National Institutes of Health, Bethesda, MD 20892, USA.
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32
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Nybakken GE, Oliphant T, Johnson S, Burke S, Diamond MS, Fremont DH. Structural basis of West Nile virus neutralization by a therapeutic antibody. Nature 2005; 437:764-9. [PMID: 16193056 PMCID: PMC7095628 DOI: 10.1038/nature03956] [Citation(s) in RCA: 302] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2005] [Accepted: 06/24/2005] [Indexed: 11/19/2022]
Abstract
West Nile virus is closely related to the human epidemic-causing dengue, yellow fever and Japanese encephalitis viruses. The study of a particularly effective monoclonal antibody, capable of protecting mice from lethal West Nile virus challenge even if administered 5 days after infection, has provided important information on the structural basis of viral neutralization. The work highlights the domain III region of the viral envelope protein as a potential target for both therapeutic antibodies and vaccines. West Nile virus is a mosquito-borne flavivirus closely related to the human epidemic-causing dengue, yellow fever and Japanese encephalitis viruses1. In establishing infection these icosahedral viruses undergo endosomal membrane fusion catalysed by envelope glycoprotein rearrangement of the putative receptor-binding domain III (DIII) and exposure of the hydrophobic fusion loop2,3,4. Humoral immunity has an essential protective function early in the course of West Nile virus infection5,6. Here, we investigate the mechanism of neutralization by the E16 monoclonal antibody that specifically binds DIII. Structurally, the E16 antibody Fab fragment engages 16 residues positioned on four loops of DIII, a consensus neutralizing epitope sequence conserved in West Nile virus and distinct in other flaviviruses. The E16 epitope protrudes from the surface of mature virions in three distinct environments7, and docking studies predict Fab binding will leave five-fold clustered epitopes exposed. We also show that E16 inhibits infection primarily at a step after viral attachment, potentially by blocking envelope glycoprotein conformational changes. Collectively, our results suggest that a vaccine strategy targeting the dominant DIII epitope may elicit safe and effective immune responses against flaviviral diseases.
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Affiliation(s)
- Grant E. Nybakken
- Departments of Pathology & Immunology, Washington University School of Medicine, Missouri 63110 St Louis, USA
| | - Theodore Oliphant
- Departments of Molecular Microbiology, Washington University School of Medicine, Missouri 63110 St Louis, USA
| | | | | | - Michael S. Diamond
- Departments of Pathology & Immunology, Washington University School of Medicine, Missouri 63110 St Louis, USA
- Departments of Molecular Microbiology, Washington University School of Medicine, Missouri 63110 St Louis, USA
- Departments of Medicine, Washington University School of Medicine, Missouri 63110 St Louis, USA
| | - Daved H. Fremont
- Departments of Pathology & Immunology, Washington University School of Medicine, Missouri 63110 St Louis, USA
- Departments of Biochemistry and Molecular Biophysics, Washington University School of Medicine, Missouri 63110 St Louis, USA
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Bossis I, Roden RBS, Gambhira R, Yang R, Tagaya M, Howley PM, Meneses PI. Interaction of tSNARE syntaxin 18 with the papillomavirus minor capsid protein mediates infection. J Virol 2005; 79:6723-31. [PMID: 15890910 PMCID: PMC1112158 DOI: 10.1128/jvi.79.11.6723-6731.2005] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The papillomavirus capsid mediates binding to the cell surface and passage of the virion to the perinuclear region during infection. To better understand how the virus traffics across the cell, we sought to identify cellular proteins that bind to the minor capsid protein L2. We have identified syntaxin 18 as a protein that interacts with bovine papillomavirus type 1 (BPV1) L2. Syntaxin 18 is a target membrane-associated soluble N-ethylmaleimide-sensitive factor-attachment protein receptor (tSNARE) that resides in the endoplasmic reticulum (ER). The ectopic expression of FLAG-tagged syntaxin 18, which disrupts ER trafficking, blocked BPV1 pseudovirion infection. Furthermore, the expression of FLAG-syntaxin 18 prevented the passage of BPV1 pseudovirions to the perinuclear region that is consistent with the ER. Genetic studies identified a highly conserved L2 domain, DKILK, comprising residues 40 to 44 that mediated BPV1 trafficking through the ER during infection via an interaction with the tSNARE syntaxin 18. Mutations within the DKILK motif of L2 that did not significantly impact virion morphogenesis or binding at the cell surface prevented the L2 interaction with syntaxin 18 and disrupted BPV1 infection.
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Affiliation(s)
- Ioannis Bossis
- Department of Pathology, Johns Hopkins University, Baltimore, Maryland 21205, USA
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34
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Dimmock NJ, Hardy SA. Valency of antibody binding to virions and its determination by surface plasmon resonance. Rev Med Virol 2004; 14:123-35. [PMID: 15027004 DOI: 10.1002/rmv.419] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
All IgGs are homobivalent, but their ability to bind bivalently to the surface of a virus particle depends mainly on a favourable spacing of cognate epitopes and the angle that the FAb arm makes with the virus surface. If the angle of binding forces the second FAb arm to point into solution, monovalent binding is inevitable. This IgG will have the same affinity as its FAb, will be less stably bound than if it were bound bivalently, cannot cross-link epitopes on the surface of a virion, and cannot neutralise by cross-linking surface proteins. However, at moderate IgG concentrations, monovalently bound IgG can reduce infectivity by aggregating virions, a phenomenon that cannot occur with IgG bound bivalently. This review describes how surface plasmon resonance can be used to determine the valency of IgG binding to enveloped and non-enveloped virus particles, and discusses the implications of this new methodology.
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Affiliation(s)
- Nigel J Dimmock
- Department of Biological Sciences, University of Warwick, Coventry CV4 7AL, UK.
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35
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Affiliation(s)
- Thomas J Smith
- Donald Danforth Plant Science Center, St. Louis, Missouri 63132, USA
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36
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Selinka HC, Giroglou T, Nowak T, Christensen ND, Sapp M. Further evidence that papillomavirus capsids exist in two distinct conformations. J Virol 2004; 77:12961-7. [PMID: 14645552 PMCID: PMC296061 DOI: 10.1128/jvi.77.24.12961-12967.2003] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cell surface heparan sulfate proteoglycans (HSPGs) serve as primary attachment receptors for human papillomaviruses (HPVs). To demonstrate that a biologically functional HPV-receptor interaction is restricted to a specific subset of HSPGs, we first explored the role of HSPG glucosaminoglycan side chain modifications. We demonstrate that HSPG O sulfation is essential for HPV binding and infection, whereas de-N-sulfated heparin interfered with VLP binding but not with HPV pseudoinfection. This points to differences in VLP-HSPG and pseudovirion-HSPG interactions. Interestingly, internalization kinetics of VLPs and pseudovirions, as measured by fluorescence-activated cell sorting analysis, also differ significantly with approximate half times of 3.5 and 7.5 h, respectively. These data suggest that differences in HSPG binding significantly influence postbinding events. We also present evidence that pseudovirions undergo a conformational change after cell attachment. A monoclonal antibody (H33.J3), which displays negligible effectiveness in preattachment neutralization assays, efficiently neutralizes cell-bound virions. However, no difference in H33.J3 binding to pseudovirions and VLPs was observed in enzyme-linked immunosorbent assay and virus capture assays. In contrast to antibody H33.B6, which displays equal efficiencies in pre- and postattachment neutralization assays, H33.J3 does not block VLP binding to heparin, demonstrating that it interferes with steps subsequent to virus binding. Our data strongly suggest that H33.J3 recognizes a conformation-dependent epitope in capsid protein L1, which undergoes a structural change after cell attachment.
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Affiliation(s)
- Hans-Christoph Selinka
- Institute for Medical Microbiology and Hygiene, University of Mainz, D-55101 Mainz, Germany
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37
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Conway JF, Watts NR, Belnap DM, Cheng N, Stahl SJ, Wingfield PT, Steven AC. Characterization of a conformational epitope on hepatitis B virus core antigen and quasiequivalent variations in antibody binding. J Virol 2003; 77:6466-73. [PMID: 12743303 PMCID: PMC155010 DOI: 10.1128/jvi.77.11.6466-6473.2003] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have characterized a conformational epitope on capsids of hepatitis B virus (HBV) by cryo-electron microscopy and three-dimensional image reconstruction of Fab-labeled capsids to approximately 10-A resolution, combined with molecular modeling. The epitope straddles the interface between two adjacent subunits and is discontinuous, consisting of five peptides-two on one subunit and three on its neighbor. Together, the two icosahedral forms of the HBV capsid-T=3 and T=4 particles-present seven quasiequivalent variants of the epitope. Of these, only three bind this Fab. Occupancy ranges from approximately 100 to approximately 0%, reflecting conformational variations in the epitope and steric blocking effects. In the former, small shifts of the component peptides have large effects on binding affinity. This approach appears to hold general promise for elucidating conformational epitopes of HBV and other viruses, including those of neutralizing and diagnostic significance.
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Affiliation(s)
- J F Conway
- Laboratoire de Microscopie Electronique, Institut de Biologie Structurale J.-P. Ebel, Grenoble 38027, France
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Abstract
In this study we have examined the pathway by which papillomaviruses infect cells, using bovine papillomavirus (BPV) virions and mouse C127 cells as the model system. By confocal microscopy, the entry of BPV virions, BPV virus-like particles (VLPs), and HPV16 VLPs were very similar. In dually exposed cells, HPV-16 VLPs and BPV virions colocalized intracellularly. BPV VLPs colocalized with AP-2, a clathrin adapter molecular and a marker of the clathrin-dependent endocytic pathway; and also with transferrin receptor, a marker of early endosomes; and Lamp-2, a marker of late endosomes and lysosomes. BPV infection was detected within 12 h of virion cell-surface binding, as measured by an RT-PCR assay. Infection was prevented by several pharmacologic inhibitors, including chlorpromazine, which blocks clathrin-dependent endocytosis and the lysosomotropic agent, bafilomycin A. By contrast, two inhibitors of caveolae-dependent uptake, filipin and nystatin, did not prevent BPV infection. We conclude that papillomaviruses infect cells via clathrin-dependent receptor-mediated endocytosis. Surprisingly, the kinetics of internalization were unusually slow for this mechanism, with the t(1/2) of entry of BPV-1 being approximately 4 h versus 5-15 min for a typical ligand.
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Affiliation(s)
- Patricia M Day
- Laboratory of Cellular Oncology, Division of Basic Sciences, National Cancer Institute, National Institutes of Health, Building 36, Room 1D-32, Bethesda, MD 20892, USA
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39
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Yang R, Day PM, Yutzy WH, Lin KY, Hung CF, Roden RBS. Cell surface-binding motifs of L2 that facilitate papillomavirus infection. J Virol 2003; 77:3531-41. [PMID: 12610128 PMCID: PMC149523 DOI: 10.1128/jvi.77.6.3531-3541.2003] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human papillomavirus type 16 (HPV16) is the primary etiologic agent of cervical carcinoma, whereas bovine papillomavirus type 1 (BPV1) causes benign fibropapillomas. However, the capsid proteins, L1 and L2, of these divergent papillomaviruses exhibit functional conservation. A peptide comprising residues 1 to 88 of BPV1 L2 binds to a variety of cell lines, but not to the monocyte-derived cell line D32, and blocks BPV1 infection of mouse C127 cells. Residues 13 to 31 of HPV16 L2 and BPV1 L2 residues 1 to 88 compete for binding to the cell surface, and their binding, unlike that of HPV16 L1/L2 virus-like particles, is unaffected by heparinase or trypsin pretreatment of HeLa cells. A fusion of HPV16 L2 peptide 13-31 and GFP binds (K(d), approximately 1 nM) to approximately 45,000 receptors per HeLa cell. Furthermore, mutation of L2 residues 18 and 19 or 21 and 22 significantly reduces both the ability of the HPV16 L2 13-31-GFP fusion protein to bind to SiHa cells and the infectivity of HPV16 pseudovirions. Antibody to BPV1 L2 peptides comprising residues 115 to 135 binds to intact BPV1 virions, but fails to neutralize at a 1:10 dilution. However, deletion of residues 91 to 129 from L2 abolishes the infectivity of BPV1, but not their binding to the cell surface. In summary, L2 residues 91 to 129 contain epitopes displayed on the virion surface and are required for infection, but not virion binding to the cell surface. Upon the binding of papillomavirus to the cell surface, residues 13 to 31 of L2 interact with a widely expressed, trypsin- and heparinase-resistant cell surface molecule and facilitate infection.
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Affiliation(s)
- Rongcun Yang
- Department of Pathology, The Johns Hopkins School of Medicine, Baltimore, Maryland 21205, USA
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40
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Bowman VD, Chase ES, Franz AWE, Chipman PR, Zhang X, Perry KL, Baker TS, Smith TJ. An antibody to the putative aphid recognition site on cucumber mosaic virus recognizes pentons but not hexons. J Virol 2002; 76:12250-8. [PMID: 12414964 PMCID: PMC136911 DOI: 10.1128/jvi.76.23.12250-12258.2002] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2002] [Accepted: 09/03/2002] [Indexed: 11/20/2022] Open
Abstract
Cucumber mosaic virus (CMV), the type member of the genus Cucumovirus (family Bromoviridae), is transmitted by aphids in a nonpersistent manner. Mutagenesis experiments identified the betaH-betaI loop of the capsid subunit as a potential key motif responsible for interactions with the insect vector. To further examine the functional characteristics of this motif, we generated monoclonal antibodies that bound to native virions but not to betaH-betaI mutants. Fab fragments from these antibodies were complexed with wild-type CMV and the virus-Fab structure was determined to 12-A resolution by using electron cryomicroscopy and image reconstruction techniques. The electron density attributed to the bound antibody has a turret-like appearance and protrudes from each of the 12 fivefold axes of the icosahedral virus. Thus, the antibody binds only to the pentameric clusters (pentons) of A subunits of the T=3 quasisymmetric virus and does not appear to bind to any of the B and C subunits that occur as hexameric clusters (hexons) at the threefold (quasi-sixfold) axes. Modeling and electron density comparisons were used to analyze the paratope-epitope interface and demonstrated that the antibody binds to three betaH-betaI loops in three adjacent A subunits in each penton. This antibody can discriminate between A and B/C subunits even though the betaH-betaI loop adopts the same structure in all 180 capsid subunits and is therefore recognizing differences in subunit arrangements. Antibodies with such character have potential use as probes of viral assembly. Our results may provide an additional rationale for designing synthetic vaccines by using symmetrical viral particles.
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Affiliation(s)
- Valorie D Bowman
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907, USA
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41
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Abstract
Papillomaviruses propagate in differentiating skin cells, and certain types are responsible for the onset of cervical cancer. We have combined image reconstructions from electron cryomicroscopy (cryoEM) of bovine papillomavirus at 9 A resolution with coordinates from the crystal structure of small virus-like particles of the human papillomavirus type 16 L1 protein to generate an atomic model of the virion. The overall fit of the L1 model into the cryoEM map is excellent, but residues 402-446 in the 'C-terminal arm' must be rebuilt. We propose a detailed model for the structure of this arm, based on two constraints: the presence of an intermolecular disulfide bond linking residues 175 and 428, and the clear identification of a feature in the image reconstruction corresponding to an alpha-helix near the C-terminus of L1. We have confirmed the presence of the disulfide bond by mass spectrometry. Our 'invading arm' model shows that papilloma- and polyomaviruses have a conserved capsid architecture. Most of the rebuilt C-terminal arm is exposed on the viral surface; it is likely to have a role in infection and in immunogenicity.
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Affiliation(s)
| | - Benes L. Trus
- Howard Hughes Medical Institute, Children’s Hospital and Harvard Medical School, 320 Longwood Avenue, Boston, MA 02115 and
Computational Bioscience and Engineering Laboratory, Division of Computer Research and Technology, and Laboratory of Structural Biology, National Institute of Arthritis, Musculoskeletal, and Skin Diseases, National Institutes of Health, Bethesda, MD 20892-5624, USA Corresponding author e-mail:
| | - Stephen C. Harrison
- Howard Hughes Medical Institute, Children’s Hospital and Harvard Medical School, 320 Longwood Avenue, Boston, MA 02115 and
Computational Bioscience and Engineering Laboratory, Division of Computer Research and Technology, and Laboratory of Structural Biology, National Institute of Arthritis, Musculoskeletal, and Skin Diseases, National Institutes of Health, Bethesda, MD 20892-5624, USA Corresponding author e-mail:
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42
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Klasse PJ, Sattentau QJ. Occupancy and mechanism in antibody-mediated neutralization of animal viruses. J Gen Virol 2002; 83:2091-2108. [PMID: 12185262 DOI: 10.1099/0022-1317-83-9-2091] [Citation(s) in RCA: 217] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Neutralization of virus infectivity by antibodies is an important component of immunity to several virus infections. Here, the immunochemical basis for the action of neutralizing antibodies, and what role their induction of conformational changes in the antigen might play, is reviewed. Theories of the mechanisms by which antibodies neutralize virus infectivity in vitro are also presented. The theoretical and empirical foundation of the hypothesis that viruses are neutralized by a single antibody per virion is critically reviewed. The relationship between antibody occupancy on virions and the mechanism of neutralization is explored. Examples of neutralization mediated through antibody interference with virus attachment and entry are discussed and test implications of refined theories of neutralization by antibody coating of virions are formulated.
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Affiliation(s)
- P J Klasse
- Jefferiss Research Trust Laboratories, Wright-Fleming Institute, Imperial College of Science, Technology and Medicine, St Mary's Campus, Norfolk Place, London W2 1PG, UK1
| | - Q J Sattentau
- Jefferiss Research Trust Laboratories, Wright-Fleming Institute, Imperial College of Science, Technology and Medicine, St Mary's Campus, Norfolk Place, London W2 1PG, UK1
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43
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Yuan H, Estes PA, Chen Y, Newsome J, Olcese VA, Garcea RL, Schlegel R. Immunization with a pentameric L1 fusion protein protects against papillomavirus infection. J Virol 2001; 75:7848-53. [PMID: 11483728 PMCID: PMC115027 DOI: 10.1128/jvi.75.17.7848-7853.2001] [Citation(s) in RCA: 111] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The prophylactic papillomavirus vaccines currently in clinical trials are composed of viral L1 capsid protein that is synthesized in eukaryotic expression systems and purified in the form of virus-like particles (VLPs). To evaluate whether VLPs are necessary for effective vaccination, we expressed the L1 protein as a glutathione S-transferase (GST) fusion protein in Escherichia coli and assayed its immunogenic activity in an established canine oral papillomavirus (COPV) model that previously validated the efficacy of VLP vaccines. The GST-COPV L1 fusion protein formed pentamers, but these capsomere-like structures did not assemble into VLPs. Despite the lack of VLP formation, the GST-COPV L1 protein retained its native conformation as determined by reactivity with conformation-specific anti-COPV antibodies. Most importantly, the GST-COPV L1 pentamers completely protected dogs from high-dose viral infection of their oral mucosa. L1 fusion proteins expressed in bacteria represent an economical alternative to VLPs as a human papillomavirus vaccine.
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Affiliation(s)
- H Yuan
- Department of Pathology, Georgetown University School of Medicine, Washington, DC 20007, USA
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44
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Burton DR, Saphire EO, Parren PW. A model for neutralization of viruses based on antibody coating of the virion surface. Curr Top Microbiol Immunol 2001; 260:109-43. [PMID: 11443871 DOI: 10.1007/978-3-662-05783-4_7] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- D R Burton
- Departments of Immunology and Molecular Biology, Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA 92037, USA
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45
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Chackerian B, Lowy DR, Schiller JT. Conjugation of a self-antigen to papillomavirus-like particles allows for efficient induction of protective autoantibodies. J Clin Invest 2001; 108:415-23. [PMID: 11489935 PMCID: PMC209354 DOI: 10.1172/jci11849] [Citation(s) in RCA: 171] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
High avidity and long-lasting autoantibodies to a self-polypeptide (TNF-alpha) were generated after parenteral vaccination of mice with low doses of virus-like particle-based (VLP-based) vaccines that were constructed by linking mouse TNF-alpha peptides to the surface of papillomavirus VLPs. High-titer autoantibodies were induced with or without coadministration of potent conventional adjuvants, but were enhanced by coadministration of CFA. Compared with immunization with the fusion protein alone, attachment to VLPs increased autoantibody titers 1,000-fold. A comparison of Ab responses against the self (TNF-alpha) and foreign components of the fusion protein showed that VLP conjugation abrogated the ability of the humoral immune system to distinguish between self and foreign. Similar levels of IgM were detected to self and foreign epitopes regardless of the assembly state of the antigen, suggesting that conjugation of self-peptides to VLPs promotes survival or expansion of mature autoreactive B cells. In a mouse model, vaccination with conjugated particles inhibited development of type II collagen-induced arthritis. Together, these results suggest a potentially flexible method to efficiently generate autoantibodies against specific self-proteins that mediate arthritis and other diseases.
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Affiliation(s)
- B Chackerian
- Laboratory of Cellular Oncology, National Institutes of Health, Bethesda, Maryland 20892-4040, USA
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46
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Lenz P, Day PM, Pang YY, Frye SA, Jensen PN, Lowy DR, Schiller JT. Papillomavirus-like particles induce acute activation of dendritic cells. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2001; 166:5346-55. [PMID: 11313370 DOI: 10.4049/jimmunol.166.9.5346] [Citation(s) in RCA: 202] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The role of viral structural proteins in the initiation of adaptive immune responses is poorly understood. To address this issue, we focused on the effect of noninfectious papillomavirus-like particles (VLPs) on dendritic cell (DC) activation. We found that murine bone marrow-derived dendritic cells (BMDCs) effectively bound and rapidly internalized bovine papillomavirus VLPS: Exposure to fully assembled VLPs of bovine papillomavirus, human papillomavirus (HPV)16 or HPV18, but not to predominately disordered HPV16 capsomers, induced acute phenotypic maturation of BMDCS: Structurally similar polyomavirus VLPs bound to the DC surface and were internalized, but failed to induce maturation. DCs that had incorporated HPV16 VLPs produced proinflammatory cytokines IL-6 and TNF-alpha; however, the release of these cytokines was delayed relative to LPS activation. Production of IL-12p70 by VLP-exposed DCs required the addition of syngeneic T cells or rIFN-gamma. Finally, BMDCs pulsed with HPV16 VLPs induced Th1-dominated primary T cell responses in vitro. Our data provide evidence that DCs respond to intact papillomavirus capsids and that they play a central role in VLP-induced immunity. These results offer a mechanistic explanation for the striking ability of papillomavirus VLP-based vaccines to induce potent T and B cell responses even in the absence of adjuvant.
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Affiliation(s)
- P Lenz
- Laboratory of Cellular Oncology, National Cancer Institute, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
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47
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Abstract
This chapter discusses in vitro and in vivo antiviral activities of antibody. Since experimentation is far easier in vitro, researchers have been sought to develop in vitro assays that are expected to predict activity in vivo. This could be important in both vaccine design and in passive antibody administration. The proposed mechanisms of in vitro neutralization range from those requiring binding of a single antibody molecule to virus to those requiring substantially complete antibody coating of virus. In vitro, antiviral activity can be separated into activity against virions and activity against infected cells. The activity against virions most often considered is neutralization that can be defined as the loss of infectivity, which ensues when antibody molecule(s) bind to a virus particle, and occurs without the involvement of any other agency. In vivo, it is conventional to distinguish phenomenologically between two types of antibody antiviral activity. One of them is the ability of antibody to protect against infection when it is present before or immediately following infection. Evidence for a number of viruses in vitro indicates that lower antibody concentrations are required to inhibit infection propagated by free virus than are required to inhibit infection propagated by cell-to-cell spread.
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Affiliation(s)
- P W Parren
- Departments of Immunology and Molecular Biology, Scripps Research Institute, La Jolla, California 92037, USA
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48
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Chen XS, Garcea RL, Goldberg I, Casini G, Harrison SC. Structure of small virus-like particles assembled from the L1 protein of human papillomavirus 16. Mol Cell 2000; 5:557-67. [PMID: 10882140 DOI: 10.1016/s1097-2765(00)80449-9] [Citation(s) in RCA: 343] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The papillomavirus major late protein, L1, forms the pentameric assembly unit of the viral shell. Recombinant HPV16 L1 pentamers assemble in vitro into capsid-like structures, and truncation of ten N-terminal residues leads to a homogeneous preparation of 12-pentamer, icosahedral particles. X-ray crystallographic analysis of these particles at 3.5 A resolution shows that L1 closely resembles VP1 from polyomaviruses. Surface loops contain the sites of sequence variation among HPV types and the locations of dominant neutralizing epitopes. The ease with which small virus-like particles may be obtained from L1 expressed in E. coli makes them attractive candidate components of a papillomavirus vaccine. Their crystal structure also provides a starting point for future vaccine design.
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Affiliation(s)
- X S Chen
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, USA
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49
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Abstract
Papillomaviruses are species- and tissue-specific double-stranded DNA viruses. These viruses cause epithelial tumours in many animals, including man. Typically, the benign warts undergo spontaneous, immune-mediated regression, most likely effected by T-cells (especially CD4, but also CD8 subsets), whereas humoral immunity can prevent new infections. Some papillomavirus infections fail to regress spontaneously and others progress to malignant epithelial tumours. Additionally, the impact of these lesions is greater in immunosuppressed individuals. Many therapies are ineffective, and there is much interest in the potential for immunological intervention in papillomavirus infections of man and animals. Vaccination can be achieved with 'live' virus, formalin-inactivated virus, synthetic virus-like particles, and DNA vaccination. There has been much recent progress in the development of such vaccines for papillomavirus infections in the rabbit, ox and dog. Success in these animal models suggests that similar approaches may prove useful for prophylactic or therapeutic vaccination against the important human papillomaviruses involved in the development of cutaneous and anogenital warts, laryngeal papillomatosis, and cervical cancer.
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Affiliation(s)
- P K Nicholls
- Department of Pathology, University of Cambridge, UK.
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50
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Ludmerer SW, McClements WL, Wang XM, Ling JC, Jansen KU, Christensen ND. HPV11 mutant virus-like particles elicit immune responses that neutralize virus and delineate a novel neutralizing domain. Virology 2000; 266:237-45. [PMID: 10639310 DOI: 10.1006/viro.1999.0083] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Characterization of the regions of human papillomaviruses (HPVs) that elicit neutralizing immune responses supports studies on viral infectivity and provides insight for the development and evaluation of prophylactic vaccines. HPV11 is a major etiologic agent of genital warts and a likely vaccine candidate. A conformationally dependent epitope for the binding of three neutralizing monoclonal antibodies (mAbs) has been mapped to residues G(131)T(132) of the L1 major capsid protein. The mAbs bind L1 only when it is assembled into virions or into virus-like particles (VLPs) that mimic the capsid structure. We were interested in identifying other domains of L1 that elicit neutralizing responses. To this end, we have generated a panel of mAbs against VLPs derived from HPV11 L1 harboring a G131S substitution. The new mAbs are unlike the neutralizing mAbs previously mapped to residues G(131)T(132) in that they bind both prototype and HPV11:G131S mutant VLPs. Some of the new mAbs neutralized virus in vitro. We have mapped epitopes for three of these new mAbs, as well as a neutralizing mAb generated against HPV11 virions, by measuring binding to HPV6 VLPs substituted with HPV11-like amino acids. Two regions are critical: one defined by HPV11 L1 residues 263-290 and the other by residues 346-349. mAbs H11.H3 and H11.G131S.G3 bind HPV6 VLPs with substitutions derived from the 346-349 region; in addition, H11.G131S.G3 binds HPV6 VLPs with substitutions derived only from the 263-290 region. Although H11.H3 does not bind HPV6 VLPs with substitutions derived from the 263-290 region, binding to HPV6 VLPs is enhanced when both sets of substitutions are present. mAbs H11.G131S.I1 and H11.G131S.K5 bind HPV6 VLPs with the 263-290 substitutions, but show little binding to HPV6 VLPs with the 346-349 substitutions. However, binding to HPV6 VLPs is enhanced when substitutions at both regions are present. The 346-349 region has not previously been described as eliciting a neutralizing response for any HPV type. In addition, the work demonstrates a complex binding site contributed by two distinct regions of L1.
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Affiliation(s)
- S W Ludmerer
- Department of Parasite Biochemistry, Merck Research Laboratories, Rahway, New Jersey, 07065, USA.
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