目的:鉴定出丙型肝炎病毒(HCV)特异性HLA-A*1101限制性和A*2402限制性CD8+T细胞表位.方法:采用T细胞表位预测软件SYFPEITHI预测HCV特异性CD8+T细胞表位,合成HLA-A*1101限制性、A*2402限制性候选表位;建立永生化的HLA-A*1101阳性、A*2402阳性B细胞株,采用竞争性肽结合实验检测候选表位与HLA-A*1101或A*2402分子的结合力;候选表位体外分别刺激HLA-A*1101阳性或A*2402阳性HCV感染者外周血单个核细胞(PBMCs)后,采用酶联免疫斑点(ELISPOT)和细胞内细胞因子染色(ICS)实验分别检测肽特异性分泌γ-干扰素(IFN-γ)的细胞的水平和(肝) 异性IFN-γ+CD8+T细胞的水平.结果:5条HLA-A*1101限制性候选表位中,NS3_609(ITLTHPITK)和NS2_165(VVFSDMETK)与HLA-A*1101分子具有高结合力.3条HLA-A*2402限制性候选表位中,NS3_373 (KCDELASKL)和NS5b_382 (YYLTRDPTI)与HLA-A*2402具有高结合力;在HLA-A*1101阳性HCV感染者PBMCs中存在NS3 609和NS2_165特异性分泌IFN-γ的CD8+T细胞,而在HLA-A*2402阳性HCV感染者PBMCs中存在NS3_373和NS5b 382特异性分泌IFN-γ的CD8+T细胞.结论:本研究证实NS3_609(ITLTHPITK)和NS2_165(WFSDMETK)为全新的HCV特异性HLA-A*1101限制性CD8+T细胞表位,NS3_373 (KCDELASKL)和NS5b_382 (YYLTRDPTI)为全新的HCV特异性HLA-A*2402限制性CD8+T细胞表位.
Objective:To identify hepatitis C virus (HCV)-specific HLA-A*1101-and A*2402-restricted CD8+ T-cell epitopes.Methods:HCV-specific CD8+ T-cell epitopes were predicted using T epitope prediction software (SYFPEITHI) and then HCV-specific HLA-A*1101 and A*2402-restricted epitope candidates were selected and synthesized.Immortalized HLA-A *1101-positive and A *2402-positive B cell lines were established.Based on above immortalized B cell lines,competitive peptide-binding assay was used to evaluate the binding affinity of epitope candidates for HLA-A*1101 and A*2402 molecules,respectively.Epitope candidates were used to stimulate PBMCs from HLA-A *1101-positive or A* 2402-positive HCV-infected patients.Enzyme-linked immunospot (ELISPOT) and intracellular cytokine staining (ICS) assay were applied to measure the frequencies of IFN-γ-secreting cells in total PBMCs and the percentages of IFN-γ+ CD8+ T cells in total CD8+ T.Results:Of five HLA-A* 1101-restricted epitope candidates,NS3_ 609 (ITLTHPITK) and NS2 165 (VVFSDMETK) had _a high affinity for HLA-A* 1101 molecules.Among three HLA-A *2402-restricted epitope candidates,NS3 373 (KCDELASKL) and NS5b_382 (YYLTRDPTI) had a high affinity for HLA-A*2402 molecules.Furthermore,high levels of NS3_609-and NS2_165-specific IFN-γ-secreting CD8+T cells were detected in HLA-A*1101-positive HCV-infected patients,whereas high levels of NS3_373-and NS5b_382-specific IFN-γ-secreting CD8+ T cells were detected in HLA-A*2402 positive HCV-infected patients.Conclusion:Our Results strongly confirmed that NS3_609 (ITLTHPITK) and NS2_165 (VVFSDMETK) are novel HCV-specific HLA-A* 1101-restricted CD8+ T-cell epitopes while NS3_373 (KCDELASKL) and NS5b_382 (YYLTRDPTI) are novel HCV-specific HLA-A*2402-restricted CD8+ T-cell epitopes.