Expression of the SART3 tumor rejection antigen in renal cell carcinoma

Purpose: We recently reported that SART3 tumor rejection antigen is recognized by HLA class I restricted cytotoxic T lymphocytes from patients with esophageal cancer. We now investigate the expression of SART3 antigen in renal cell carcinoma to identify an appropriate molecule that may be used in specific immunotherapy of renal cell carcinoma. Materials and Methods: Renal cell carcinoma and nontumorous kidney tissues were obtained at surgery. A section of each sample was minced with scissors and stored at -80C until use. SART3 antigen expression was examined in uncultured renal cell carcinoma and nontumorous kidney tissues. We also evaluated the ability of derived peptides to include cytotoxic T lymphocytes in peripheral blood mononuclear cells from patients with renal cell carcinoma. Results: The SART3 antigen was detected in all renal cell carcinoma cell lines, primary cultures of renal cell carcinoma and nontumorous kidney tissues, and in the cytosol of 57% and 15% of renal cell carcinoma and nontumorous kidney tissues, respectively. HLA-A2402 restricted and tumor specific cytotoxic T lymphocytes (KE4) used in cloning of the SART3 gene were significantly cytotoxic to cells from renal cell carcinoma cell lines and primary cultures of renal cell carcinoma tissue but they did not lyse normal cells, including those from primary cultures of nontumorous kidney tissue. The SART3 peptides derived from positions 109-118 and 315-323 induced HLA-A24 restricted cytotoxic T lymphocytes to renal cell carcinoma cells from peripheral blood mononuclear cells of patients with renal cell carcinoma. Conclusions: The SART3 antigen and derived peptides may be applied to the specific immunotherapy of HLA-A24(+) renal cell carcinoma.