Twenty-one PSGR-derived peptides predicted by an immuno-informatics approach based on the HLA-A2 binding motif were examined for their ability to induce peptide-specific T cell responses in peripheral blood mononuclear cells (PBMCs) obtained from either HLA-A2+ healthy donors or HLA-A2+ prostate cancer patients. The recognition of HLA-A2 positive and PSGR expressing LNCaP cells was also tested. Three peptides, PSGR3, PSGR4 and PSGR14 frequently induced peptide-specific T cell responses in PBMCs from both healthy donors and prostate cancer patients, and are recognized by CD8+ T cells in an HLA-A2 dependent manner. These peptide-specific T cells recognize HLA-A2+ and PSGR+ tumor cells, and killed LNCaP prostate cancer cells in an HLA class I-restricted manner. These PSGR-derived peptides identified are useful as diagnostic markers as well as immune targets for anticancer vaccines.
