Estradiol-induced release of immunosuppressive agent from human malignant melanoma cells.

One human skin fibroblast (HSF) and three human malignant melanoma cell (HMMC) lines were examined for responsiveness to 17 alpha- and 17 beta- estradiol. Responsiveness was monitored by changes in 3H-uridine uptake (nucleic acid synthesis). 3H-leucine uptake (protein synthesis) and to complement-mediated serum cytotoxicity. 17 alpha-Estradiol had no effect on any of the examined cell lines. 17 beta-Estradiol had no effect on HSF, but increased HMMC resistance to complement-mediated serum cytotoxicity, nucleic acid and protein synthesis. An immunosuppressive agent was isolated from HMMC lysates and spent cell-free culture medium.