COMMON HUMAN MELANOMA-ASSOCIATED ANTIGEN(S) DETECTED BY MONOCLONAL-ANTIBODIES

Abstract

Hybridoma cells were derived from a fusion between mouse P3-NSl/1Ag4 myeloma cells and spleen cells from a mouse immunized with membrane-enriched fractions from the human Me-43 melanoma cells. Of the 26 hybrids obtained, 7 secreted antibodies which reacted with the melanoma cell line used for immunization as assessed by an indirect antibody-binding radioimmunoassay. The specificity of the antibodies produced by the 7 positive hybrids was further investigated on 16 melanoma cell lines, 15 other tumors and 14 lymphoblastoid cell lines. The antibodies from 4 positive hybrids showed a broad reactivity; those from 3 hybrids reacted exclusively with melanoma cells. The antibodies from 2 of these 3 hybrids, .alpha.-Mel/5 and .alpha.-Mel/14, seem to be directed against common melanoma antigen(s) since they reacted with all (with 1 exception) of the 16 melanoma cell lines tested; antibodies from the 3rd hybrid, .alpha.-Mel/7, reacted with 5 of the 16 melanoma lines. Reciprocal binding inhibition tests using [3H]leucine-labeled antibodies showed that .alpha.-Mel/5 and .alpha.-Mel/14 antibodies were directed against different antigenic determinants.