The DAM gene family encodes a new group of tumor-specific antigens recognized by human leukocyte antigen A2-restricted cytotoxic T lymphocytes.

The DAM family of genes has a high degree of homology with MAGE, both in nucleotide sequence and in neoplastic tissue-specific expression. This study describes, for the first time, the identification of CTLs specific for a peptide epitope encoded by DAM genes. A human leukocyte antigen (HLA)-A2-restricted CTL clone was raised against a peptide, D10/6-271, encoded by codons 271-279 in the DAM cDNA. The corresponding peptide in the MAGE-3 sequence, M3-271, has been shown previously to be a natural T-cell epitope for HLA-A2-restricted CTLs recognizing the MAGE-3 protein. The D10/6-271-specific CTL clone required approximately 3 nM exogenous peptide for half-maximal lysis of target cells and was able to specifically recognize endogenous DAM antigen on HLA-A2+ melanoma cells infected with a vaccinia vector recombinant for gene DAM-6. These data suggest that DAM genes might encode a new group of tumor-specific antigens useful for the design of specific antitumor vaccines.