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Pierce BG, Felbinger N, Metcalf M, Toth EA, Ofek G, Fuerst TR. Hepatitis C Virus E1E2 Structure, Diversity, and Implications for Vaccine Development. Viruses 2024; 16:803. [PMID: 38793684 PMCID: PMC11125608 DOI: 10.3390/v16050803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Revised: 05/02/2024] [Accepted: 05/15/2024] [Indexed: 05/26/2024] Open
Abstract
Hepatitis C virus (HCV) is a major medical health burden and the leading cause of chronic liver disease and cancer worldwide. More than 58 million people are chronically infected with HCV, with 1.5 million new infections occurring each year. An effective HCV vaccine is a major public health and medical need as recognized by the World Health Organization. However, due to the high variability of the virus and its ability to escape the immune response, HCV rapidly accumulates mutations, making vaccine development a formidable challenge. An effective vaccine must elicit broadly neutralizing antibodies (bnAbs) in a consistent fashion. After decades of studies from basic research through clinical development, the antigen of choice is considered the E1E2 envelope glycoprotein due to conserved, broadly neutralizing antigenic domains located in the constituent subunits of E1, E2, and the E1E2 heterodimeric complex itself. The challenge has been elicitation of robust humoral and cellular responses leading to broad virus neutralization due to the relatively low immunogenicity of this antigen. In view of this challenge, structure-based vaccine design approaches to stabilize key antigenic domains have been hampered due to the lack of E1E2 atomic-level resolution structures to guide them. Another challenge has been the development of a delivery platform in which a multivalent form of the antigen can be presented in order to elicit a more robust anti-HCV immune response. Recent nanoparticle vaccines are gaining prominence in the field due to their ability to facilitate a controlled multivalent presentation and trafficking to lymph nodes, where they can interact with both the cellular and humoral components of the immune system. This review focuses on recent advances in understanding the E1E2 heterodimeric structure to facilitate a rational design approach and the potential for development of a multivalent nanoparticle-based HCV E1E2 vaccine. Both aspects are considered important in the development of an effective HCV vaccine that can effectively address viral diversity and escape.
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Affiliation(s)
- Brian G. Pierce
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA; (B.G.P.); (N.F.); (M.M.); (E.A.T.); (G.O.)
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA
| | - Nathaniel Felbinger
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA; (B.G.P.); (N.F.); (M.M.); (E.A.T.); (G.O.)
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA
| | - Matthew Metcalf
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA; (B.G.P.); (N.F.); (M.M.); (E.A.T.); (G.O.)
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA
| | - Eric A. Toth
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA; (B.G.P.); (N.F.); (M.M.); (E.A.T.); (G.O.)
| | - Gilad Ofek
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA; (B.G.P.); (N.F.); (M.M.); (E.A.T.); (G.O.)
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA
| | - Thomas R. Fuerst
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA; (B.G.P.); (N.F.); (M.M.); (E.A.T.); (G.O.)
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA
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Kumar A, Rohe TC, Elrod EJ, Khan AG, Dearborn AD, Kissinger R, Grakoui A, Marcotrigiano J. Regions of hepatitis C virus E2 required for membrane association. Nat Commun 2023; 14:433. [PMID: 36702826 PMCID: PMC9879980 DOI: 10.1038/s41467-023-36183-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 01/19/2023] [Indexed: 01/27/2023] Open
Abstract
Hepatitis C virus (HCV) uses a hybrid entry mechanism. Current structural data suggest that upon exposure to low pH and Cluster of Differentiation 81 (CD81), the amino terminus of envelope glycoprotein E2 becomes ordered and releases an internal loop with two invariant aromatic residues into the host membrane. Here, we present the structure of an amino-terminally truncated E2 with the membrane binding loop in a bent conformation and the aromatic side chains sequestered. Comparison with three previously reported E2 structures with the same Fab indicates that this internal loop is flexible, and that local context influences the exposure of hydrophobic residues. Biochemical assays show that the amino-terminally truncated E2 lacks the baseline membrane-binding capacity of the E2 ectodomain. Thus, the amino terminal region is a critical determinant for both CD81 and membrane interaction. These results provide new insights into the HCV entry mechanism.
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Affiliation(s)
- Ashish Kumar
- Structural Virology Section, Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Tiana C Rohe
- Structural Virology Section, Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Elizabeth J Elrod
- Emory National Primate Research Center, Division of Microbiology and Immunology, Emory Vaccine Center, Emory University School of Medicine, Atlanta, GA, 30329, USA
| | - Abdul G Khan
- Center for Advanced Biotechnology and Medicine, Rutgers, The State University of New Jersey, Piscataway, NJ, 08854, USA
| | - Altaira D Dearborn
- Structural Virology Section, Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Ryan Kissinger
- Research Technology Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, 59840, USA
| | - Arash Grakoui
- Emory National Primate Research Center, Division of Microbiology and Immunology, Emory Vaccine Center, Emory University School of Medicine, Atlanta, GA, 30329, USA
| | - Joseph Marcotrigiano
- Structural Virology Section, Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, 20892, USA.
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Mechanisms and Consequences of Genetic Variation in Hepatitis C Virus (HCV). Curr Top Microbiol Immunol 2023; 439:237-264. [PMID: 36592248 DOI: 10.1007/978-3-031-15640-3_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Chronic infection with hepatitis C virus (HCV) is an important contributor to the global incidence of liver diseases, including liver cirrhosis and hepatocellular carcinoma. Although common for single-stranded RNA viruses, HCV displays a remarkable high level of genetic diversity, produced primarily by the error-prone viral polymerase and host immune pressure. The high genetic heterogeneity of HCV has led to the evolution of several distinct genotypes and subtypes, with important consequences for pathogenesis, and clinical outcomes. Genetic variability constitutes an evasion mechanism against immune suppression, allowing the virus to evolve epitope escape mutants that avoid immune recognition. Thus, heterogeneity and variability of the HCV genome represent a great hindrance for the development of vaccines against HCV. In addition, the high genetic plasticity of HCV allows the virus to rapidly develop antiviral resistance mutations, leading to treatment failure and potentially representing a major hindrance for the cure of chronic HCV patients. In this chapter, we will present the central role that genetic diversity has in the viral life cycle and epidemiology of HCV. Incorporation errors and recombination, both the result of HCV polymerase activity, represent the main mechanisms of HCV evolution. The molecular details of both mechanisms have been only partially clarified and will be presented in the following sections. Finally, we will discuss the major consequences of HCV genetic diversity, namely its capacity to rapidly evolve antiviral and immunological escape variants that represent an important limitation for clearance of acute HCV, for treatment of chronic hepatitis C and for broadly protective vaccines.
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Prentoe J, Janitzek CM, Velázquez-Moctezuma R, Soerensen A, Jørgensen T, Clemmensen S, Soroka V, Thrane S, Theander T, Nielsen MA, Salanti A, Bukh J, Sander AF. Two-component vaccine consisting of virus-like particles displaying hepatitis C virus envelope protein 2 oligomers. NPJ Vaccines 2022; 7:148. [DOI: 10.1038/s41541-022-00570-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 10/31/2022] [Indexed: 11/16/2022] Open
Abstract
AbstractDevelopment of B-cell-based hepatitis C virus (HCV) vaccines that induce broadly neutralizing antibodies (bNAbs) is hindered by extensive sequence diversity and low immunogenicity of envelope glycoprotein vaccine candidates, most notably soluble E2 (sE2). To overcome this, we employed two-component approaches using self-assembling virus-like particles (cVLPs; component 1), displaying monomeric or oligomeric forms of HCV sE2 (sE2mono or sE2oligo; component 2). Immunization studies were performed in BALB/c mice and the neutralizing capacity of vaccine-induced antibodies was tested in cultured-virus-neutralizations, using HCV of genotypes 1–6. sE2-cVLP vaccines induced significantly higher levels of NAbs (p = 0.0065) compared to corresponding sE2 vaccines. Additionally, sE2oligo-cVLP was superior to sE2mono-cVLP in inducing bNAbs. Interestingly, human monoclonal antibody AR2A had reduced binding in ELISA to sE2oligo-cVLP compared with sE2mono-cVLP and competition ELISA using mouse sera from vaccinated animals indicated that sE2oligo-cVLP induced significantly less non-bNAbs AR2A (p = 0.0043) and AR1B (p = 0.017). Thus, cVLP-displayed oligomeric sE2 shows promise as an HCV vaccine candidate.
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Wolfisberg R, Thorselius CE, Salinas E, Elrod E, Trivedi S, Nielsen L, Fahnøe U, Kapoor A, Grakoui A, Rice CM, Bukh J, Holmbeck K, Scheel TKH. Neutralization and receptor use of infectious culture-derived rat hepacivirus as a model for HCV. Hepatology 2022; 76:1506-1519. [PMID: 35445423 PMCID: PMC9585093 DOI: 10.1002/hep.32535] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 04/06/2022] [Accepted: 04/08/2022] [Indexed: 12/31/2022]
Abstract
BACKGROUND AND AIMS Lack of tractable immunocompetent animal models amenable to robust experimental challenge impedes vaccine efforts for HCV. Infection with rodent hepacivirus from Rattus norvegicus (RHV-rn1) in rats shares HCV-defining characteristics, including liver tropism, chronicity, and pathology. RHV in vitro cultivation would facilitate genetic studies on particle production, host factor interactions, and evaluation of antibody neutralization guiding HCV vaccine approaches. APPROACH AND RESULTS We report an infectious reverse genetic cell culture system for RHV-rn1 using highly permissive rat hepatoma cells and adaptive mutations in the E2, NS4B, and NS5A viral proteins. Cell culture-derived RHV-rn1 particles (RHVcc) share hallmark biophysical characteristics of HCV and are infectious in mice and rats. Culture adaptive mutations attenuated RHVcc in immunocompetent rats, and the mutations reverted following prolonged infection, but not in severe combined immunodeficiency (SCID) mice, suggesting that adaptive immune pressure is a primary driver of reversion. Accordingly, sera from RHVcc-infected SCID mice or the early acute phase of immunocompetent mice and rats were infectious in culture. We further established an in vitro RHVcc neutralization assay, and observed neutralizing activity of rat sera specifically from the chronic phase of infection. Finally, we found that scavenger receptor class B type I promoted RHV-rn1 entry in vitro and in vivo. CONCLUSIONS The RHV-rn1 infectious cell culture system enables studies of humoral immune responses against hepacivirus infection. Moreover, recapitulation of the entire RHV-rn1 infectious cycle in cell culture will facilitate reverse genetic studies and the exploration of tropism and virus-host interactions.
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Affiliation(s)
- Raphael Wolfisberg
- Copenhagen Hepatitis C ProgramDepartment of Infectious DiseasesHvidovre HospitalCopenhagenDenmark,Department of Immunology and MicrobiologyUniversity of CopenhagenCopenhagenDenmark
| | - Caroline E. Thorselius
- Copenhagen Hepatitis C ProgramDepartment of Infectious DiseasesHvidovre HospitalCopenhagenDenmark,Department of Immunology and MicrobiologyUniversity of CopenhagenCopenhagenDenmark
| | - Eduardo Salinas
- Emory Vaccine CenterDivision of Microbiology and ImmunologyYerkes Research Primate CenterEmory University School of MedicineAtlantaGeorgiaUSA,Division of Infectious DiseasesDepartment of MedicineEmory University School of MedicineAtlantaGeorgiaUSA
| | - Elizabeth Elrod
- Emory Vaccine CenterDivision of Microbiology and ImmunologyYerkes Research Primate CenterEmory University School of MedicineAtlantaGeorgiaUSA,Division of Infectious DiseasesDepartment of MedicineEmory University School of MedicineAtlantaGeorgiaUSA
| | - Sheetal Trivedi
- Center for Vaccines and ImmunityResearch Institute at Nationwide Children’s HospitalColumbusOhioUSA
| | - Louise Nielsen
- Copenhagen Hepatitis C ProgramDepartment of Infectious DiseasesHvidovre HospitalCopenhagenDenmark,Department of Immunology and MicrobiologyUniversity of CopenhagenCopenhagenDenmark
| | - Ulrik Fahnøe
- Copenhagen Hepatitis C ProgramDepartment of Infectious DiseasesHvidovre HospitalCopenhagenDenmark,Department of Immunology and MicrobiologyUniversity of CopenhagenCopenhagenDenmark
| | - Amit Kapoor
- Center for Vaccines and ImmunityResearch Institute at Nationwide Children’s HospitalColumbusOhioUSA
| | - Arash Grakoui
- Emory Vaccine CenterDivision of Microbiology and ImmunologyYerkes Research Primate CenterEmory University School of MedicineAtlantaGeorgiaUSA,Division of Infectious DiseasesDepartment of MedicineEmory University School of MedicineAtlantaGeorgiaUSA
| | - Charles M. Rice
- Laboratory of Virology and Infectious DiseaseThe Rockefeller UniversityNew YorkNew YorkUSA
| | - Jens Bukh
- Copenhagen Hepatitis C ProgramDepartment of Infectious DiseasesHvidovre HospitalCopenhagenDenmark,Department of Immunology and MicrobiologyUniversity of CopenhagenCopenhagenDenmark
| | - Kenn Holmbeck
- Copenhagen Hepatitis C ProgramDepartment of Infectious DiseasesHvidovre HospitalCopenhagenDenmark,Department of Immunology and MicrobiologyUniversity of CopenhagenCopenhagenDenmark
| | - Troels K. H. Scheel
- Copenhagen Hepatitis C ProgramDepartment of Infectious DiseasesHvidovre HospitalCopenhagenDenmark,Department of Immunology and MicrobiologyUniversity of CopenhagenCopenhagenDenmark,Laboratory of Virology and Infectious DiseaseThe Rockefeller UniversityNew YorkNew YorkUSA
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Walker C, Ou J, Foung S. Editorial overview: Engineering elimination of chronic viral hepatitis. Curr Opin Virol 2022; 52:57-59. [PMID: 34861638 DOI: 10.1016/j.coviro.2021.10.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Christopher Walker
- Center for Vaccines and Immunity, Nationwide Children's Hospital and Department of Pediatrics, College of Medicine, The Ohio State University. Columbus, OH, 43205, United States.
| | - James Ou
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, United States
| | - Steven Foung
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, 94305, United States
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