A recombinant peptide consisting of amino acid residues 240 to 251 of the enzyme tyrosinase, a protein frequently expressed by melanoma cells, with serine substitution at position 244 to improve immunogenicity. Vaccination with tyrosinase:240-251(244S) may stimulate the host immune response to mount a cytotoxic T lymphocyte (CTL) response against tyrosinase-expressing tumor cells. [ ]