Immunologic recognition of malignant melanoma by autologous T lymphocytes

T lymphocytes specifically recognizing autologous tumor cells in vitro can be generated from melanoma patients. Recognition of tumor cells by both CD4 and CD8 lymphocytes is mediated through the T-cell receptor and is restricted by HLA antigens. Although HLA-A2 has been identified as a restricting allele for many melanoma-specific cytotoxic T lymphocytes, T cells directed against antigens unique to each patient's tumor as well as antigens common to melanomas from unrelated individuals can be restricted by several different HLA alleles. A common melanoma antigen recognized in association with HLA-A1 has now been identified. The antigen is a nonapeptide derived from the gene MAGE1, a normal cellular gene preferentially expressed in a variety of solid tumors. Melanoma cells have been found to produce a soluble form of the intracellular adhesion molecule-1. Soluble intercellular adhesion molecule-1 effectively inhibits cell-mediated cytotoxicity in vitro, raising the possibility that its expression in vivo could promote escape of the tumor cells from immune effectors.