Genetic immunization and comprehensive screening approaches in HLA-A2 transgenic mice lead to the identification of three novel epitopes in hepatitis C virus NS3 antigen

• Published in: Journal of medical virology 2004-11, Vol.74 (3), p.397-405
• Main Authors: Martin, P., Parroche, P., Chatel, L., Barretto, C., Beck, A., Trépo, C., Bain, C., Lone, Y.C., Inchauspé, G., Fournillier, Anne
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; CD8-Positive T-Lymphocytes - immunology; cytotoxic T lymphocytes; Epitope Mapping; Epitopes - genetics; HCV; Hepacivirus - genetics; Hepacivirus - immunology; Hepatitis C Antigens - genetics; Hepatitis C, Chronic - genetics; Hepatitis C, Chronic - immunology; Hepatitis C, Chronic - virology; HLA-A2 Antigen - genetics; Humans; IFNγ production; immune response; Immunization; In Vitro Techniques; Interferon-gamma - biosynthesis; Interleukin-10 - biosynthesis; Mice; Mice, Transgenic; PBMC; T epitopes; Vaccines, DNA - genetics; Viral Hepatitis Vaccines - genetics; Viral Nonstructural Proteins - genetics; Viral Nonstructural Proteins - immunology
• ISSN: 0146-6615; 1096-9071
• DOI: 10.1002/jmv.20189

Interferon‐γ (IFNγ)‐producing CD8+ T cells have been shown to play a key role in the control or eradication of hepatitis C virus (HCV) infections. In particular, T cells specific of the non‐structural protein 3 (NS3) are often associated with control of viremia. The aim of the study was to identify novel HLA‐A2 restricted CD8+ T cell epitopes specific of NS3 using a combination of comprehensive approaches. HLA‐A2.1 transgenic mice were immunized with a DNA vaccine optimized for NS3 specific epitope presentation and induced CD8+ T cell reactivity was screened using 42 algorithm‐predicted peptides as well as a library of 78 overlapping 15‐mer peptides spanning the whole protein. Three epitopes mapping within the NS3 protease (GLL: aa 1038–1047) or helicase (ATL: aa 1260–1268 and TLH: aa 1617–1625) were identified. These epitopes, which display similar and high in vitro binding capacities to soluble HLA‐A2 molecules, are able to induce either cytotoxic T lymphocytes (CTL) and/or IFNγ‐producing T cells. Comparative in vitro target cell sensitization studies revealed a higher immunogenicity of the GLL peptide as compared with both ATL and TLH peptides. This peptide was capable to recall in vitro HCV‐specific IFNγ and IL‐10‐producing T cells from peripheral blood mononuclear cells (PBMC) of chronically infected patients. These data increase the pool of NS3‐specific CD8+ T cell epitopes available to analyze HCV associated immunity and could contribute to the design and evaluation of candidate vaccines. J. Med. Virol. 74:397–405, 2004. © 2004 Wiley‐Liss, Inc.