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Identification of a new HLA‐A*0201‐restricted CD8+ T cell epitope from hepatocellular carcinoma‐associated antigen HCA587

For the development of peptide‐based cancer immunotherapies, we aimed to identify specific HLA‐A*0201‐restricted CTL epitopes in hepatocellular carcinoma (HCC) associated antigen HCA587, which has been identified as a member of the cancer/testis (CT) antigens highly expressed in HCC. We first combined the use of an HLA‐A*0201/peptide binding algorithm and T2 binding assays with the induction of specific CD8+ T cell lines from normal donors by in vitro priming with high‐affinity peptides, then IFN‐γ release and cytotoxicity assays were employed to identify the specific HLA‐A*0201 CD8+ T cell epitope using peptide‐loaded T2 cells or the HCA587 protein+ HCC cell line HepG2. In the six candidate synthesized peptides, two peptides showed higher binding ability in T2 binding assays. No. 2 peptide, encompassing amino acid residues FLAKLNNTV (HCA587317−325), was able to activate a HCA587‐specific CD8+ T‐cell response in human lymphocyte cultures from two normal donors and two HCC patients, and these HCA587‐specific CD8+ T cells recognized peptide‐pulsed T2 cells as well as the HCA587 protein+ HCC cell line HepG2 in IFN‐γ release and cytotoxicity assays. The results indicate that no. 2 peptide is a new HLA‐A*0201‐restricted CTL epitope capable of inducing HCA587‐specific CTLs. Our data suggest that identification of this new HCA587/HLA‐A*0201 peptide FLAKLNNTV may facilitate the design of peptide‐based immunotherapies for the treatment of HCA587‐bearing HCC patients.