First, to solve the problems of the present invention, the present inventors confirmed the presence of ovarian cancer antigen-specific T cells in the peripheral blood of ovarian cancer patients by using an experimental system that detects combinations of CD4 and IL-4 or IFN&gamma；. Next, using analogue peptides of the core protein MUC 16 of the ovarian cancer-associated antigen CA 125, the present inventors revealed that antigen-specific CD4-positive T cells are present at an average frequency of about 4% in the peripheral mononuclear cells of patients and healthy subjects. Then, the present inventors analyzed the epitope for T cells in the core protein MUC 16 of the ovarian cancer-associated antigen CA 125, and determined the amino acid sequence FTLNFTITN (SEQ ID NO: 1) to be a shorter epitope. The present inventors further discovered that the analogue peptide OVCA11: GHTAPGPLLVPFTLNFTITN (SEQ ID NO:11) is suitable for T cell activation.
