A TYROSINASE NONAPEPTIDE PRESENTED BY HLA-B44 IS RECOGNIZED ON A HUMAN-MELANOMA BY AUTOLOGOUS CYTOLYTIC T-LYMPHOCYTES

The human tyrosinase gene has been reported previously to code for two distinct antigens recognized on HLA-A2 melanoma cells by autologous c ytolytic T lymphocytes (CTL). By stimulating lymphocytes of melanoma p atient MZ2 with a subclone of the tumor cell line of this patient, we obtained a CTL clone that lysed this subclone but did not lyse other s ubcloncs of the Same melanoma cell line. The sensitive melanoma subclo ne was found to express a much higher level of tyrosinase than the oth ers, suggesting that the antigen recognized bv the CTL might be encode d by tyrosinase. Transfection of a tyrosinase cDNA demonstrated that t he CTL clone indeed recognized a tyrosinase product presented by HLA-B 4403. The relevant antigenic peptide corresponds to residues 192-200 of the tyrosinase protein. Lymphoblastoid cells of the B4402 subtype were not recognized by the CTL following incubation wth the peptide. N evertheless, by stimulating in vitro lymphocytes of a healthy HLA-B44 02 donor with autologous adherent cells pulsed with the same peptide, we obtained a CTL clone which recognized tumor cells expressing tyrosi nase and HLA-B4 402. As HLA-B44 is expressed in 24 % of Caucasians, t he tyrosinase-B44 antigen may constitute a useful target for specific immunotherapy of melanoma.