New tumour-restricted melanoma antigens as defined by cytotoxic T-cell responses

Several tumour antigens have been molecularly defined during the last few years and three main groups of melanoma-associated antigens have been identified according to their pattern of expression. Despite their wide expression in the Caucasian population, human leukocyte antigen (HLA) class I-presenting molecules, alternate to HLA-A2.1, have received little attention. To further explore the complexity of HLA class I-presented melanoma epitopes, we looked for the existence of other antigens recognized by T cells in HLA-A3.1 and HLA-A2.1 restriction. The pattern of recognition identified by HLA-A3.1 or HLA-A2.1-restricted T-cell lines and clones indicated the existence of a novel category of antigens represented by proteins expressed by melanomase but not by melanocytes.