Expression of surface antigens and its relation to parameters of malignancy in human malignant melanoma

Summary Human malignant melanoma cell lines were assayed for secretion of plasminogen activator (PA) and for growth in the nude mouse. It was observed that cell lines that were high producers of PA also grew in the nude mouse. In order to detect differences in membrane constituents of cells related to these parameters of malignancy, antisera were raised in non-human primates against the high producer (Mel A-375) and the non-producer cell of PA (SK-Mel 25). After extensive absorption the two antisera showed little or no cross-reactivity with the other cell line. Several subclones were isolated from SK-Mel 25 and assayed for PA production and growth in the nude mouse. Two sublines (S 5 and S 13) were found that produced moderate amounts of PA and grew in the nude mouse, whereas five other sublines were negative in both respects. By means of antisera against sublines it could be shown that patterns of surface antigens were distinct from that of the parental line.