Mammary leukaemia (ML) antigen isolated from L 1210 leukaemia cells.

Crude 3 M KCl extracts from L 1210 cells and purified ML antigen were characterized and the presence of ML antigens was verified by various anti-ML sera, as well as by antisera to disrupted MMTV B particles. Selected ML-positive fractions from preparative polyacrylamide electrophoresis and purified ML antigen isolated by affinity chromatography were analyzed by polyacrylamide disc electrophoresis. With both procedures the same sharp band was obtained. The molecular weight of both preparations was found to be 73,500 as estimated. The relationship between ML antigen, MMTV antigenic products and cell-associated viral proteins is discussed.