A PEPTIDE RECOGNIZED BY HUMAN CYTOLYTIC T-LYMPHOCYTES ON HLA-A2 MELANOMAS IS ENCODED BY AN INTRON SEQUENCE OF THE N-ACETYLGLUCOSAMINYLTRANSFERASE-V GENE

A cytolytic T lymphocyte (CTL) clone that lyses many HLA-A2 melanomas was derived from a population of tumor-infiltrating lymphocytes of an HLA-A2 melanoma patient. The gene coding for the antigen recognized by this CTL was identified by transfection of a cDNA library. It is the gene which has been reported to code for N-acetylglucosaminyltransfera se V (GnT-V). Remarkably, the antigenic peptide recognized by the CTL is encoded by a sequence located in an intron. In contrast to the full y spliced GnT-V mRNA, which was found in a wide range of normal and tu moral tissues, the mRNA containing the intron region coding for the an tigen was not found at a significant level in normal tissues. This mRN A was observed to be present in about 50% of melanomas. Our results su ggest that a promoter located near the end of the relevant intron is a ctivated in melanoma cells, resulting in the production of an mRNA cod ing for the antigen.