IDENTIFICATION OF TRP-2 AS A HUMAN TUMOR-ANTIGEN RECOGNIZED BY CYTOTOXIC T-LYMPHOCYTES

The infusion of TIL586 along with interleukin-2 into the autologous pa tient with metastatic melanoma resulted in the objective regression of tumor. A gene encoding a tumor antigen recognized by TIL586 was previ ously isolated and shown to encode gp75 or TRP-1. Here we report that TRP-2 was identified as a second tumor antigen recognized by a HLA-A31 -restricted CTL clone derived from the TIL586 cell Line. The peptide L LPGGRPYR epitope was subsequently identified from the coding region of TRP-2 based on studies of the recognition of truncated TRP-2 cDNAs an d the HLA-A31 binding motif. This epitope peptide was cells for lysis by a CTL clone at 1 nM peptide concentration. Although some modified p eptides could be recognized by the CTL clone, none were found to be be tter recognized by T cells than the parental peptide. Like other melam ona differentiation antigens, TRP-2 was only expressed in melanoma, me lanocytes, and retina, but not in other human tissues tested.