Dataset Information

Role of the E2 Hypervariable Region (HVR1) in the Immunogenicity of a Recombinant Hepatitis C Virus Vaccine.

ABSTRACT: Current evidence supports a protective role for virus-neutralizing antibodies in immunity against hepatitis C virus (HCV) infection. Many cross-neutralizing monoclonal antibodies have been identified. These antibodies have been shown to provide protection or to clear infection in animal models. Previous clinical trials have shown that a gpE1/gpE2 vaccine can induce antibodies that neutralize the in vitro infectivity of all the major cell culture-derived HCV (HCVcc) genotypes around the world. However, cross-neutralization appeared to favor certain genotypes, with significant but lower neutralization against others. HCV may employ epitope masking to avoid antibody-mediated neutralization. Hypervariable region 1 (HVR1) at the amino terminus of glycoprotein E2 has been shown to restrict access to many neutralizing antibodies. Consistent with this, other groups have reported that recombinant viruses lacking HVR1 are hypersensitive to neutralization. It has been proposed that gpE1/gpE2 lacking this domain could be a better vaccine antigen to induce broadly neutralizing antibodies. In this study, we examined the immunogenicity of recombinant gpE1/gpE2 lacking HVR1 (?HVR1). Our results indicate that wild-type (WT) and ?HVR1 gpE1/gpE2 antigens induced antibodies targeting many well-characterized cross-genotype-neutralizing epitopes. However, while the WT gpE1/gpE2 vaccine can induce cross-genotype protection against various genotypes of HCVcc and/or HCV-pseudotyped virus (HCVpp), antisera from ?HVR1 gpE1/gpE2-immunized animals exhibited either reduced homologous neutralization activity compared to that of the WT or heterologous neutralization activity similar to that of the WT. These data suggest that ?HVR1 gpE1/gpE2 is not a superior vaccine antigen. Based on previously reported chimpanzee protection data using WT gpE1/gpE2 and our current findings, we are preparing a combination vaccine including wild-type recombinant gpE1/gpE2 for clinical testing in the future.IMPORTANCE An HCV vaccine is an unmet medical need. Current evidence suggests that neutralizing antibodies play an important role in virus clearance, along with cellular immune responses. Previous clinical data showed that gpE1/gpE2 can effectively induce cross-neutralizing antibodies, although they favor certain genotypes. HCV employs HVR1 within gpE2 to evade host immune control. It has been hypothesized that the removal of this domain would improve the production of cross-neutralizing antibodies. In this study, we compared the immunogenicities of WT and ?HVR1 gpE1/gpE2 antigens as vaccine candidates. Our results indicate that the ?HVR1 gpE1/gpE2 antigen confers no advantages in the neutralization of HCV compared with the WT antigen. Previously, we showed that this WT antigen remains the only vaccine candidate to protect chimpanzees from chronic infection, contains multiple cross-neutralizing epitopes, and is well tolerated and immunogenic in humans. The current data support the further clinical development of this vaccine antigen component.

SUBMITTER: Law JLM

PROVIDER: S-EPMC5952160 | biostudies-literature | 2018 Jun

REPOSITORIES: biostudies-literature

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Role of the E2 Hypervariable Region (HVR1) in the Immunogenicity of a Recombinant Hepatitis C Virus Vaccine.

Law John L M JLM Logan Michael M Wong Jason J Kundu Juthika J Hockman Darren D Landi Amir A Chen Chao C Crawford Kevin K Wininger Mark M Johnson Janelle J Mesa Prince Catalina C Dudek Elzbieta E Mehta Ninad N Tyrrell D Lorne DL Houghton Michael M

Journal of virology 20180514 11

Current evidence supports a protective role for virus-neutralizing antibodies in immunity against hepatitis C virus (HCV) infection. Many cross-neutralizing monoclonal antibodies have been identified. These antibodies have been shown to provide protection or to clear infection in animal models. Previous clinical trials have shown that a gpE1/gpE2 vaccine can induce antibodies that neutralize the <i>in vitro</i> infectivity of all the major cell culture-derived HCV (HCVcc) genotypes around the wo ...[more]

PMID: 29540595

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Project description:Hepatitis C virus (HCV) envelope glycoproteins E1 and E2 form a heterodimer and mediate receptor interactions and viral fusion. Both E1 and E2 are targets of the neutralizing antibody (NAb) response and are candidates for the production of vaccines that generate humoral immunity. Previous studies demonstrated that N-terminal hypervariable region 1 (HVR1) can modulate the neutralization potential of monoclonal antibodies (MAbs), but no information is available on the influence of HVR2 or the intergenotypic variable region (igVR) on antigenicity. In this study, we examined how the variable regions influence the antigenicity of the receptor binding domain of E2 spanning HCV polyprotein residues 384 to 661 (E2661) using a panel of MAbs raised against E2661 and E2661 lacking HVR1, HVR2, and the igVR (?123) and well-characterized MAbs isolated from infected humans. We show for a subset of both neutralizing and nonneutralizing MAbs that all three variable regions decrease the ability of MAbs to bind E2661 and reduce the ability of MAbs to inhibit E2-CD81 interactions. In addition, we describe a new MAb directed toward the region spanning residues 411 to 428 of E2 (MAb24) that demonstrates broad neutralization against all 7 genotypes of HCV. The ability of MAb24 to inhibit E2-CD81 interactions is strongly influenced by the three variable regions. Our data suggest that HVR1, HVR2, and the igVR modulate exposure of epitopes on the core domain of E2 and their ability to prevent E2-CD81 interactions. These studies suggest that the function of HVR2 and the igVR is to modulate antibody recognition of glycoprotein E2 and may contribute to immune evasion.This study reveals conformational and antigenic differences between the ?123 and intact E2661 glycoproteins and provides new structural and functional data about the three variable regions and their role in occluding neutralizing and nonneutralizing epitopes on the E2 core domain. The variable regions may therefore function to reduce the ability of HCV to elicit NAbs directed toward the conserved core domain. Future studies aimed at generating a three-dimensional structure for intact E2 containing HVR1, and the adjoining NAb epitope at residues 412 to 428, together with HVR2, will reveal how the variable regions modulate antigenic structure.

Project description:Hepatitis C virus (HCV) infection remains a major worldwide health problem despite development of highly effective direct-acting antivirals. HCV rapidly evolves upon acute infection and generates multiple viral variants (quasispecies), leading to immune evasion and persistent viral infection. Identification of epitopes of broadly neutralizing anti-HCV antibodies (nAbs) is critical to guide HCV vaccine development. In this study, we developed a new reverse genetics system for HCV infection based on trans-complementation of viral structural proteins. The HCV genome (JFH1 strain) lacking the structural protein-coding sequence can be efficiently rescued by ectopic expression of core-E1-E2-p7-NS2 (core-NS2) or core-E1-E2-p7 (core-p7) in trans, leading to production of single-round infectious virions designated HCVΔS. JFH1-based HCVΔS can be also rescued by expressing core-NS2 of other HCV genotypes, rendering it an efficient tool to display the structural proteins of HCV strains of interests. Furthermore, we successfully rescued HCVΔS with structural proteins from clinical isolates. Multiple viral structural proteins with different sensitivities to nAbs were identified from a same patient serum, demonstrating the genetic diversity of HCV quasispecies in vivo Interestingly, the structural protein-coding sequences of highly divergent viral quasispecies from the same patient can be clustered based on their hypervariable region 1 (HVR1) in viral envelope protein E2, which critically dictates the sensitivity to neutralizing antibodies. In summary, we developed a novel reverse genetics system that efficiently displays viral structural proteins from HCV clinical isolates, and analysis of quasispecies from the same patient using this system demonstrated that E2 HVR1 is the major determinant of viral evolution in vivoIMPORTANCE A cell culture model that can recapitulate the diversity of HCV quasispecies in patients is important for analysis of neutralizing epitopes and HCV vaccine development. In this study, we developed a new reverse genetics system for HCV infection based on trans-complementation of viral structural proteins (HCVΔS). This system can be used to display structural proteins of HCV strains of multiple genotypes as well as clinical isolates. By using this system, we showed that multiple different HCV structural proteins from a same patient were displayed on HCVΔS. Interestingly, these variant structural proteins within the same patient can be classified according to the sequence of HVR1in E2, which dictates viral sensitivity to nAbs and viral evolution in vivo Our work provided a new tool to study highly divergent HCV quasispecies and shed light on underlying mechanisms driving HCV evolution.

Dataset Information

Role of the E2 Hypervariable Region (HVR1) in the Immunogenicity of a Recombinant Hepatitis C Virus Vaccine.

Publications

Role of the E2 Hypervariable Region (HVR1) in the Immunogenicity of a Recombinant Hepatitis C Virus Vaccine.

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