A HER2/NEU-derived peptide, a K-d-restricted murine tumor rejection antigen, induces HER2-specific HLA-A2402-restricted CD8(+) cytotoxic T lymphocytes

We have identified an H-2K(d)-binding peptide, HER2p780 (PYVSRLLGI), derive d from murine HER2/neu (HER2), that can induce HER2-specific murine cytotox ic T lymphocytes (CTL). Weekly vaccination of BALB/c mice by syngeneic dend ritic cells pulsed with HER2p780 peptide, entirely common to murine and hum an HER2, suppressed growth of pretransplanted HER2-expressing syngeneic tum ors. A HER2-expressing human cancer cell line SKOV3 transfected with murine H-2K(d) cDNA could also be lysed by HER2p780-specific murine CTLs, indicat ing that human HER2-expressing cancer cells can process and present the cog nate peptide in the context of H-2K(d). Since H-2K(d) and HLA-A2402 molecul es have similar anchor motifs, the possibility of inducing HER2-specific CT L activity with HER2p780 in HLA-A2402 individuals was examined. CD8(+) CTL clones specific for HER2-expressing cancer cell lines were established from peripheral blood lymphocytes with HLA-A2402 by repeatedly sensitizing with peptide-pulsed autologous dendritic cells as well as peripheral blood mono nuclear cells. Detailed analysis of their specificity revealed that the cyt otoxicity of CTL clones is specific for the cognate peptide with HLA-A2402 restriction. The results suggest that HER2p780 is a unique peptide that may function as a tumor rejection antigen peptide in HLA-A2402 individuals, as it was directly proven here to function in a murine tumor system. Int. J. Cancer 87:553-558, 2000. (C) 2000 Wiley-Liss, Inc.