Identification of a Shared HLA-A*0201-restricted T-Cell Epitope from the Melanoma Antigen Tyrosinase-related Protein 2 (TRP2)

MR Parkhurst, EB Fitzgerald, S Southwood, A Sette… - Cancer research, 1998 - AACR
MR Parkhurst, EB Fitzgerald, S Southwood, A Sette, SA Rosenberg, Y Kawakami
Cancer research, 1998AACR
Abstract Tyrosinase-related protein 2 (TRP2) is a melanosomal enzyme expressed in most
mammalian melanocytes and melanomas. This protein has been identified as a melanoma
antigen recognized by tumor reactive CTLs derived from tumor infiltrating lymphocytes in the
context of HLA-A31 and HLA-A33. The frequencies of these HLA-A alleles among
melanoma patients in the United States is low (∼ 6% for HLA-A31 and∼ 2% for HLA-A33)
compared with that of HLA-A* 0201 (∼ 46%). Therefore, to extend significantly the use of …
Abstract
Tyrosinase-related protein 2 (TRP2) is a melanosomal enzyme expressed in most mammalian melanocytes and melanomas. This protein has been identified as a melanoma antigen recognized by tumor reactive CTLs derived from tumor infiltrating lymphocytes in the context of HLA-A31 and HLA-A33. The frequencies of these HLA-A alleles among melanoma patients in the United States is low (∼6% for HLA-A31 and ∼2% for HLA-A33) compared with that of HLA-A*0201 (∼46%). Therefore, to extend significantly the use of TRP2-based immunotherapies for the treatment of patients with melanoma, we searched for new HLA-A*0201-restricted epitopes from this protein by screening TRP2-derived peptides for the induction of melanoma-reactive CTL. Fifty-one peptides were selected from TRP2 based on a permissive HLA-A*0201 binding motif, and the 21 peptides with the highest experimentally determined binding affinities were used to stimulate peripheral blood lymphocytes from HLA-A*0201+ melanoma patients in vitro. One peptide, TRP2(180–188) (SVYDFFVWL), induced CTLs from three of four patients that specifically recognized peptide-pulsed T2 cells, COS-7 cells expressing HLA-A*0201 and TRP2, and HLA-A2+ TRP2+ melanomas. TRP2(180–188) is identical to a previously identified TRP2 epitope recognized by murine melanoma-reactive CTLs in the context of H-2Kb. These results suggest that TRP2 may be useful for the development of murine tumor immunotherapy models and for the treatment of melanoma patients who are diverse in HLA expression.
AACR