Cleavage and polyadenylation specificity factor (CPSF)-derived peptides can induce HLA-A2-restricted and tumor-specific CTLs in the majority of gastrointestinal cancer patients.

To identify CTL-directed antigens in gastrointestinal cancer, we have investigated antigens recognized by the HLA-A2-restricted CTL line established from T cells infiltrating into colon cancer and report herein cleavage and polyadenylation specificity factor (CPSF) as a potent antigen holding peptides capable of inducing CTLs. Five peptides at amino acid positions 250-258, 392-400, 534-542, 1296-1304 and 1359-1368 of CPSF, which were recognized by the CTL line, were found to have the ability to induce HLA-A2-restricted and tumor-specific CTLs in peripheral blood mononuclear cells of the majority (69%, 11/16) of gastrointestinal cancer patients with different HLA-A2 subtypes. Thus, these peptides might be appropriate molecules for use in the peptide-based specific immunotherapy of HLA-A2(+) patients with gastrointestinal cancers.