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.
Interferon-gamma (IFN gamma)-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 IFN gamma-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 IFN gamma 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.
Martin
P
P
FRE 2736 CNRS / bioMérieux, IFR 128 BioSciences Lyon-Gerland, Lyon, France.
Parroche
P
P
Chatel
L
L
Barretto
C
C
Beck
A
A
Trépo
C
C
Bain
C
C
Lone
Y C
YC
Inchauspé
G
G
Fournillier
Anne
A
D000595:Amino Acid Sequence; D000818:Animals; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D018604:Epitope Mapping; D000939:Epitopes / Q000235:genetics; D015789:HLA-A2 Antigen / Q000235:genetics; D016174:Hepacivirus / Q000235:genetics* / Q000276:immunology*; D018936:Hepatitis C Antigens / Q000235:genetics*; D019698:Hepatitis C, Chronic / Q000235:genetics / Q000276:immunology / Q000821:virology; D006801:Humans; D007114:Immunization; D066298:In Vitro Techniques; D007371:Interferon-gamma / Q000096:biosynthesis; D016753:Interleukin-10 / Q000096:biosynthesis; D051379:Mice; D008822:Mice, Transgenic; D019444:Vaccines, DNA / Q000235:genetics; D014761:Viral Hepatitis Vaccines / Q000235:genetics*; D017361:Viral Nonstructural Proteins / Q000235:genetics* / Q000276:immunology*; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases
D000939:Epitopes; D015789:HLA-A2 Antigen; D018936:Hepatitis C Antigens; D007371:Interferon-gamma; D016753:Interleukin-10; D019444:Vaccines, DNA; D014761:Viral Hepatitis Vaccines; D017361:Viral Nonstructural Proteins; C084422:NS3 protein, hepatitis C virus; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases