Identification of cytotoxic T-lymphocyte epitopes from hepatocellular car-cinoma antigen MAGEC2 / 中国病理生理杂志

ABSTRACT

AIM:To observe whether modified epitopes from hepatocellular carcinoma antigen MAGEC 2 have HLA-A2-restricted antitumor ability.METHODS:HLA-A2 epitopes from MAGEC2 protein were predicted by NetCTL 1. 2,SYFPEITHI and IEDB.The change of binding anchor motifs by replacing anchor residues created the modified peptides from MAGEC2.The binding affinity of the peptides to HLA-A*0201 molecule was evaluated by T2 cells binding assay. ELISPOT assay and intracellular cytokine staining were used to investigate the ability of the peptides inducing specific re -stricted cytotoxic T-lymphocytes(CTLs)to release interferon-γ(IFN-γ).The ability of the peptides to induce T-cell re-sponse was investigated by cytotoxicity assay in vitro.RESULTS:The candidate peptides P248, P248-1Y,P356,P356-1Y,P356-2L and P356-1Y2L showed moderate affinity toward HLA-A2 molecule.T2 binding assay showed that P248-1Y and P356-1Y2L showed significantly higher affinity for HLA-A2 than the native peptides.ELISPOT assay and intracellular cytokine staining showed P248, P248-1Y, P356 and P356-1Y2L were able to induce specific CTLs to release IFN-γ. ELISPOT assay showed that significantly higher levels of IFN-γrelease were induced by P248-1Y and P356-1Y2L than the native peptides.The CTLs induced by P248,P248-1Y,P356 and P356-1Y2L lysed HepG2 cells,and P248-1Y and P356-1Y2L peptide-specific CTLs showed higher cytotoxicity against HepG 2 cells than the native peptide-specific CTLs(P<0.05).CONCLUSION: Compared with the native peptides, modified epitopes P248-1Y and P356-1Y2L have higher binding affinity with HLA-A2 and retain immunogenecity.In addition, the antitumor immunity effects of modified epitope P248-1Y and P356-1Y2L are stronger than the native peptides.The peptides P248-1Y and P356-1Y2L are excellent HLA-A2-restricted CTL epitopes from tumor antigen MAGEC 2, which could serve as new candidates towards antitumor peptide vaccines.