[Cancer vaccine therapy using peptides derived from tumor-rejection antigens]

A number of genes coding tumor antigens have recently been isolated from human melanoma cell lines. The antigens encoded by these genes are recognized by autologous cytotoxic T lymphocytes (CTL) in the context of HLA class I molecules, and the antigenic peptides have been identified. These tumor-rejection antigens include tumor-specific shared antigens, differentiation antigens, or antigens specific for individual tumors. Tumor-specific CTLs have been generated from peripheral blood mononuclear cells (PBMC) of healthy donors or patients with malignant tumors by in vitro stimulation with peptide epitopes derived from tumor-rejection antigens. Furthermore, induction of peptide-specific CTL in PBMC has been observed in patients following the immunization with the antigenic peptides in vivo. Based on these findings, clinical vaccine trials using these antigenic peptides have recently begun in patients with melanoma as well as other tumors that express these antigens, and some tumor responses have been seen in a limited number of patients. Therefore, in order to evaluate the efficacy of the vaccine therapy against various malignant tumors, further clinical studies are now under way.