IDENTIFICATION OF A GP100 EPITOPE RECOGNIZED BY HLA-A3 RESTRICTED MELANOMA INFILTRATING LYMPHOCYTES

The large majority of known melanoma-associated antigenic peptides pre sented by MHC class I molecules are presented by the most frequent all ele, HLA-A0201. Thus although a significant percentage of Caucasians express HLA-A3, no melanoma-associated antigenic peptide presented by this allele has yet been identified. We show here that the T cell clon e M45-10 isolated from tumor infiltrating lymphocytes recovered from a melanoma biopsy recognizes the gp100-derived peptide ALLAVGATK presen ted by HLA-A0301. Since gp100 is expressed on most melanoma cells, ou r results imply that the gp100-based anti-melanoma strategies develope d for individuals expressing HLA-A2 will also be applicable to those e xpressing HLA-AS (about one Caucasian in four). gp100 is therefore a p articularly promising melanoma antigen, as different peptides derived from it can be presented by at least two different frequently encounte red HLA class I molecules.