Antibody-selected mimics of hepatitis C virus hypervariable region 1 activate both primary and memory Th lymphocytes

Hepatology. 2003 Sep;38(3):653-63. doi: 10.1053/jhep.2003.50387.

Abstract

An ideal strategy that leads to a vaccine aimed at controlling viral escape may be that of preventing the replication of escape mutants by eliciting a T- and B-cell repertoire directed against many viral variants. The hypervariable region 1 (HVR1) of the putative envelope 2 protein that presents B and T epitopes shown to induce protective immunity against hepatitis C virus (HCV), might be suitable for this purpose if its immunogenicity can be improved by generating mimics that induce broad, highly cross-reactive, anti-HVR1 responses. Recently we described a successful approach to select HVR1 mimics (mimotopes) incorporating the variability found in a great number of viral variants. In this report we explore whether these mimotopes, designed to mimic B-cell epitopes, also mimic helper T-cell epitopes. The first interesting observation is that mimotopes selected for their reactivity to HVR1-specific antibodies of infected patients also do express HVR1 T-cell epitopes, suggesting that similar constraints govern HVR1-specific humoral and cellular immune responses. Moreover, some HVR1 mimotopes stimulate a multispecific CD4(+) T-cell repertoire that effectively cross-reacts with HVR1 native sequences. This may significantly limit effects as a T-cell receptor (TCR) antagonist frequently exerted by natural HVR1-variants on HVR1-specific T-cell responses. In conclusion, these data lend strong support to using HVR1 mimotopes in vaccines designed to prevent replication of escape mutants.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • B-Lymphocytes / immunology
  • Cell Line
  • Complementarity Determining Regions*
  • Cross Reactions
  • Epitopes / analysis
  • Female
  • Hepacivirus / genetics*
  • Hepatitis C, Chronic / immunology
  • Hepatitis C, Chronic / virology*
  • Humans
  • Immunologic Memory / immunology*
  • Lymphocyte Activation / immunology*
  • Lymphocytes / immunology*
  • Male
  • Middle Aged
  • Molecular Mimicry / immunology*
  • Receptors, Antigen, T-Cell / antagonists & inhibitors
  • T-Lymphocytes / immunology
  • T-Lymphocytes, Helper-Inducer / immunology*

Substances

  • Complementarity Determining Regions
  • Epitopes
  • Receptors, Antigen, T-Cell