title: A pigmentation-associated, differentiation antigen of human melanoma defined by a precipitating antibody in human serum.
abstract: Antibodies in the serum of melanoma patient AU precipitate an antigen from 125I-labelled extracts of cultured autologous melanoma cells. The antigen, which is probably not a cell surface component, is present in other pigmented melanomas but not in non-pigmented melanomas or other tumor cell types, and the amount of antigen is correlated with the degree of pigmentation. These conclusions are based on absorption experiments with 11 pigmented melanomas, 8 non-pigmented melanomas, 3 astrocytomas, 12 carcinomas of various histological types, I leukemia, 2 EB-virus-transformed B lymphocyte lines, and human erythrocytes. The antigen was also detected in cultured human melanocytes. It has a molecular weight of 70,000, an isoelectric point of pH 5.3, and it binds to concanavalin A-Sepharose. Ninety-six sera from other melanoma patients were examined and none of them precipitated this antigen. As described previously, the serum from patient AU also has antibodies to a unique (Class I) tumor antigen found only on AU melanoma cells. The pigmentation-associated, differentiation antigen and the unique antigen are clearly different in their distribution, but some relationship between these unusual antibody responses is possible.
mesh_terms: D000912:Antibodies, Neoplasm / Q000032:analysis*; D000951:Antigens, Neoplasm / Q000032:analysis*; D001254:Astrocytoma / Q000276:immunology; D002277:Carcinoma / Q000276:immunology; D002454:Cell Differentiation; D002460:Cell Line; D000939:Epitopes; D006801:Humans; D008544:Melanocytes / Q000276:immunology* / Q000473:pathology; D008545:Melanoma / Q000276:immunology* / Q000473:pathology / Q000503:physiopathology; D010858:Pigmentation; D011233:Precipitin Tests
chemical_list: D000912:Antibodies, Neoplasm; D000951:Antigens, Neoplasm; D000939:Epitopes