scholarly journals Hepatitis C Virus Hypervariable Region 1 Modulates Receptor Interactions, Conceals the CD81 Binding Site, and Protects Conserved Neutralizing Epitopes

2010 ◽  
Vol 84 (11) ◽  
pp. 5751-5763 ◽  
Author(s):  
Dorothea Bankwitz ◽  
Eike Steinmann ◽  
Julia Bitzegeio ◽  
Sandra Ciesek ◽  
Martina Friesland ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Virus Replication ◽  
Immune Escape ◽  
Hypervariable Region ◽  
Low Density ◽  
Wild Type ◽  
Hypervariable Region 1 ◽  
Cd81 Binding ◽  
Neutralizing Epitopes

ABSTRACT The variability of the hepatitis C virus (HCV), which likely contributes to immune escape, is most pronounced in hypervariable region 1 (HVR1) of viral envelope protein 2. This domain is the target for neutralizing antibodies, and its deletion attenuates replication in vivo. Here we characterized the relevance of HVR1 for virus replication in vitro using cell culture-derived HCV. We show that HVR1 is dispensable for RNA replication. However, viruses lacking HVR1 (ΔHVR1) are less infectious, and separation by density gradients revealed that the population of ΔHVR1 virions comprises fewer particles with low density. Strikingly, ΔHVR1 particles with intermediate density (1.12 g/ml) are as infectious as wild-type virions, while those with low density (1.02 to 1.08 g/ml) are poorly infectious, despite quantities of RNA and core similar to those in wild-type particles. Moreover, ΔHVR1 particles exhibited impaired fusion, a defect that was partially restored by an E1 mutation (I347L), which also rescues infectivity and which was selected during long-term culture. Finally, ΔHVR1 particles were no longer neutralized by SR-B1-specific immunoglobulins but were more prone to neutralization and precipitation by soluble CD81, E2-specific monoclonal antibodies, and patient sera. These results suggest that HVR1 influences the biophysical properties of released viruses and that this domain is particularly important for infectivity of low-density particles. Moreover, they indicate that HVR1 obstructs the viral CD81 binding site and conserved neutralizing epitopes. These functions likely optimize virus replication, facilitate immune escape, and thus foster establishment and maintenance of a chronic infection.

scholarly journals Construction and characterization of chimeric hepatitis C virus E2 glycoproteins: analysis of regions critical for glycoprotein aggregation and CD81 binding

2000 ◽  
Vol 81 (12) ◽  
pp. 2873-2883 ◽  
Author(s):  
Arvind H. Patel ◽  
Jonny Wood ◽  
Francois Penin ◽  
Jean Dubuisson ◽  
J. A. McKeating
Keyword(s):  
Amino Acids ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Protein Misfolding ◽  
Hypervariable Region ◽  
Genotype 1A ◽  
Hypervariable Region 1 ◽  
Glycosylation Sites ◽  
Cd81 Binding

We compared the ability of two closely related truncated E2 glycoproteins (E2660) derived from hepatitis C virus (HCV) genotype 1a strains Glasgow (Gla) and H77c to bind a panel of conformation-dependent monoclonal antibodies (MAbs) and CD81. In contrast to H77c, Gla E2660 formed disulfide-linked high molecular mass aggregates and failed to react with conformation-dependent MAbs and CD81. To delineate amino acid (aa) regions associated with protein aggregation and CD81 binding, several Gla–H77c E2660 chimeric glycoproteins were constructed. Chimeras C1, C2 and C6, carrying aa 525–660 of Gla E2660, produced disulfide-linked aggregates and failed to bind CD81 and conformation-dependent MAbs, suggesting that amino acids within this region are responsible for protein misfolding. The presence of Gla hypervariable region 1 (aa 384–406) on H77 E2660, chimera C4, had no effect on protein folding or CD81 binding. Chimeras C3 and C5, carrying aa 384–524 or 407–524 of Gla E2660, respectively, were recognized by conformation-dependent MAbs and yet failed to bind CD81, suggesting that amino acids in region 407–524 are important in modulating CD81 interaction without affecting antigen folding. Comparison of Gla and H77c E2660 aa sequences with those of genotype 1a and divergent genotypes identified a number of variant amino acids, including two putative N-linked glycosylation sites at positions 476 and 532. However, introduction of G476N–G478S and/or D532N in Gla E2660 had no effect on antigenicity or aggregation.

scholarly journals A single amino acid change in the hypervariable region 1 of hepatitis C virus genotype 4a aids humoral immune escape

2016 ◽  
Vol 97 (6) ◽  
pp. 1345-1349 ◽  
Author(s):  
Amruta S. Naik ◽  
Brendan A. Palmer ◽  
Orla Crosbie ◽  
Elizabeth Kenny-Walsh ◽  
Liam J. Fanning
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Amino Acid Change ◽  
Immune Escape ◽  
Hypervariable Region ◽  
Single Amino Acid ◽  
Virus Genotype ◽  
Humoral Immune ◽  
Hypervariable Region 1 ◽  
Single Amino Acid Change

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

2018 ◽  
Vol 92 (11) ◽  
Author(s):  
John L. M. Law ◽  
Michael Logan ◽  
Jason Wong ◽  
Juthika Kundu ◽  
Darren Hockman ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Neutralizing Antibodies ◽  
Hypervariable Region ◽  
Vaccine Antigen ◽  
Current Evidence ◽  
Pseudotyped Virus ◽  
Wild Type ◽  
Neutralization Activity ◽  
Neutralizing Epitopes

ABSTRACTCurrent 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 thein vitroinfectivity 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 (ΔHVR1). Our results indicate that wild-type (WT) and ΔHVR1 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 ΔHVR1 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 ΔHVR1 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.IMPORTANCEAn 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 ΔHVR1 gpE1/gpE2 antigens as vaccine candidates. Our results indicate that the ΔHVR1 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.

scholarly journals Hypervariable region 1 variant acting as TCR antagonist affects hepatitis C virus-specific CD4+T cell repertoire by favoring CD95-mediated apoptosis

2005 ◽  
Vol 78 (2) ◽  
pp. 372-382 ◽  
Author(s):  
Cristiano Scottà ◽  
Loretta Tuosto ◽  
Anna Maria Masci ◽  
Luigi Racioppi ◽  
Enza Piccolella ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
T Cell ◽  
Hypervariable Region ◽  
Cd4 T Cell ◽  
T Cell Repertoire ◽  
Cell Repertoire ◽  
Hypervariable Region 1

scholarly journals Ultradeep Pyrosequencing of Hepatitis C Virus Hypervariable Region 1 in Quasispecies Analysis

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Kamila Caraballo Cortés ◽  
Osvaldo Zagordi ◽  
Tomasz Laskus ◽  
Rafał Płoski ◽  
Iwona Bukowska-Ośko ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Hypervariable Region ◽  
454 Sequencing ◽  
Correction Method ◽  
Sequencing Error ◽  
Hypervariable Region 1 ◽  
Reconstruction Methods ◽  
Sequencing Strategy

Genetic variability of hepatitis C virus (HCV) determines pathogenesis of infection, including viral persistence and resistance to treatment. The aim of the present study was to characterize HCV genetic heterogeneity within a hypervariable region 1 (HVR1) of a chronically infected patient by ultradeep 454 sequencing strategy. Three independent sequencing error correction methods were applied. First correction method (Method I) implemented cut-off for genetic variants present in less than 1%. In the second method (Method II), a condition to call a variant was bidirectional coverage of sequencing reads. Third method (Method III) usedShort Read Assembly into Haplotypes(ShoRAH) program. After the application of these three different algorithms, HVR1 population consisted of 8, 40, and 186 genetic haplotypes. The most sensitive method was ShoRAH, allowing to reconstruct haplotypes constituting as little as 0.013% of the population. The most abundant genetic variant constituted only 10.5%. Seventeen haplotypes were present in a frequency above 1%, and there was wide dispersion of the population into very sparse haplotypes. Our results indicate that HCV HVR1 heterogeneity andquasispeciespopulation structure may be reconstructed by ultradeep sequencing. However, credible analysis requires proper reconstruction methods, which would distinguish sequencing error from real variabilityin vivo.

scholarly journals Production and Characterization of Monoclonal Antibodies Specific for a Conserved Epitope within Hepatitis C Virus Hypervariable Region 1

2001 ◽  
Vol 75 (24) ◽  
pp. 12412-12420 ◽  
Author(s):  
Chengyao Li ◽  
Daniel Candotti ◽  
Jean-Pierre Allain
Keyword(s):  
Monoclonal Antibodies ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Neutralizing Antibodies ◽  
Hypervariable Region ◽  
Passive Immunization ◽  
Immune Recognition ◽  
Hypervariable Region 1 ◽  
Neutralizing Capacity ◽  
Conserved Epitope

ABSTRACT Frequent mutations in hypervariable region 1 (HVR1) of the main envelope protein of hepatitis C virus (HCV) is a major mechanism of persistence by escaping the host immune recognition. HVR1 contains an epitope eliciting neutralizing antibodies. This study was aimed to prepare broadly cross-reacting, high-affinity, monoclonal antibodies (MAb) to the HVR1 C terminus of HCV with potential therapeutic neutralizing capacity. A conserved amino residue group of glycine (G) at position 23 and glutamic acid (Q) at position 26 in HVR1 was confirmed as a key epitope against which two MAbs were selected and characterized. MAbs 2P24 and 15H4 were immunoglobulin G1 kappa chain [IgG1(κ)], cross-reacted with 32 and 30 of 39 random C-terminal HVR1 peptides, respectively, and did not react with other HCV peptides. The VH of 2P24 and 15H4 heavy chains originated from Igh germ line v gene family 1 and 8, respectively. In contrast, the VL κ sequences were highly homologous. The affinity (K d ) of 2P24 and 15H4 (10−9 or 10−8 M with two immunizing peptides and 10−8 M with two nonimmunizing HVR1 peptides) paralleled the reactivity obtained with peptide enzyme immunoassay. MAbs 2P24 and 15H4 captured 25 of 31 (81%) HCV in unselected patients' plasmas. These antibodies also blocked HCV binding to Molt-4 cells in a dose-dependent fashion. The data presented suggest that broadly cross-reactive MAbs to a conserved epitope within HCV HVR1 can be produced. Clinical application for passive immunization in HCV-related chronic liver disease and after liver transplantation is considered.

Sign in / Sign up

Export Citation Format

Share Document