A MAGE-A1 peptide is recognized on HLA-B7 human tumors by cytolytic T lymphocytes

Antigens encoded by MAGE genes are of particular interest for cancer immuno therapy because of their strict tumoral specificity and because they are sh ared by many tumors. MAGE antigenic peptides are currently used in therapeu tic vaccination trials. The identification of additional antigenic peptides is likely to be important for the future of these clinical trials in order to increase the number of patients eligible for these vaccinations and to analyze in detail the T-cell response of vaccinated patients. We describe h ere the isolation of a cytolytic T lymphocyte (CTL) clone which recognizes a new MAGE-A1 peptide, RVRFFFPSL (MAGE-Al289-297), which is presented by HL A-B7. This CTL clone lysed HLA-B7 tumor cells expressing IMAGE-AI. HLA-B7 i s expressed by approximately 20% of Caucasians.