Differentiation of Friend virus-induced leukemia cells.

A long-term cultured Friend leukemia cell is able to differentiate along the erythrocytic series following treatment with some substances and that can be demonstrated by a conjugated erythrocyte membrane-specific antibody technique. Differentiation is induced by inhibition of DNA synthesis and by dimethylsulfoxide (DMSO), erythropoietin (EP) and Vitamin B12 (B12), and other agents. The effective substances were divided into 2 groups by the mode of differentiation of Friend cells. A differentiated state continues for several days when cells are re-cultured in the medium without substances. The decreased tumorigenecity of differentiated cells is proved by back transplantation to mice.