Melanoma patients respond to a new HLA‐A01‐presented antigenic ligand derived from a multi‐epitope region of melanoma antigen TRP‐2

Tyrosinase‐related protein‐2 (TRP‐2) is a known target antigen of spontaneous cytotoxic T cell responses in melanoma patients. Its frequent expression in metastatic tumors suggests that it might be an ideal candidate antigen for T cell‐based immunotherapy. To provide knowledge about TRP‐2‐derived T cell epitopes useful for immunotherapy we applied a “reverse immunology strategy” based on repeated in vitro peptide stimulation of peripheral blood lymphocytes (PBL) from normal donors with predicted HLA‐A*01 ligands. This led to the identification of TRP‐2181–190 as the first HLA‐A*01‐presented TRP‐2‐derived epitope. T‐cell lines specific for peptide TRP‐2181–190 could be established from PBL of 50% of the normal HLA‐A*01+ donors tested. Such T cells responded specifically to autologous dendritic cells transduced virally with TRP‐2, as well as to HLA‐A*01+, TRP‐2+ melanoma cells, although tumor cells had to be pretreated with IFN‐γ to become susceptible to T cell recognition. Interestingly, short‐term in vitro peptide stimulation of PBL from HLA‐A*01+ melanoma patients showed the presence of TRP‐2181–190‐reactive CD8+ T cells in some donors, suggesting their in vivo sensitization. Because TRP‐2181–190 overlaps with the known HLA‐A*0201‐presented epitope TRP‐2180–188, an 11mer peptide encompassing both epitopes might be of specific value for vaccination of a broad population of melanoma patients. © 2005 Wiley‐Liss, Inc.