Induction of tumor specific cytotoxic T lymphocytes in prostate cancer using prostatic acid phosphatase derived HLA-A2402 binding peptide

Purpose: Human prostatic acid phosphatase is a prostate specific differentiation antigen. Prostatic acid phosphatase levels increase in the serum of patients with prostate cancer and its peptide from positions 299 to 307 (PAP 299-307) is recognized by HLA-A2 restricted cytotoxic T lymphocytes. We investigated whether HIA-A2402 binding prostatic acid phosphatase derived peptides induce HLA-A2402 restricted, tumor specific cytotoxic T lymphocytes from the peripheral blood mononuclear cells of patients with prostate cancer. Materials and Methods: Peptide binding activity was measured with RMA-S-A*A2402 cell lines and flow cytometry. Cytotoxic T-lymphocyte activity of the peripheral blood mononuclear cells of patients with prostate cancer and healthy donors was measured by interferon-gamma and (51) creatinine release assays. Prostatic acid phosphatase expression in the tumor cell lines at the messenger RNA and protein levels was investigated by reverse transcriptase-polymerase chain reaction and immunohistochemical analysis, respectively. Results: An HIA-A2402 binding, prostatic acid phosphatase derived peptide consisting of the prostatic acid phosphatase amino acid sequence from positions 213 to 221 (PAP 213-221, LYCESVHNF) showed the ability to induce HLA-A2402 restricted and tumor specific cytotoxic T lymphocytes, which are cytoxic to prostatic acid phosphatase positive tumor cells from the peripheral blood mononuclear cells of patients with prostate cancer. Conclusions: PAP 213-221 may be appropriate as a cancer vaccine for specific immunotherapy in patients with HLA-A2402 positive prostate cancer.