Carcinoembryonic antigen from human malignant melanoma cells. I. Production and shedding characteristics.

Two major findings are reported in the present studies: (a) Long-term cultivation, followed by cloning, of a human malignant melanoma HMMC-ShA cell line gave melanotic and amelanotic cell variants. During in vitro proliferation, the melanotic melanoma (HMMC-ShAE+) cells released carcinoembryonic antigen (CEA) and an inhibitor of phytohaemagglutinin-induced lymphocyte stimulation. Gel filtration patterns of CEA on Sephadex-G200 varied from one culture condition to another. Glycosylation-deficient CEA obtained from cells harvested from media supplemented with non-toxic levels of tunicamycin showed lower molecular weight and delayed filtration through Sephadex-G200. (b) Human melanotic melanoma (HMMC-ShAE+) differed from amelanotic melanoma (HMMC-ShA-) and glycosylation-deficient cells in the amount of CEA and in the suppression of lymphocyte response activity which they shed into the medium and as well as in oncogenicity in athymic nu/nu BALB/c mice.