A factor in human saliva that induces differentiation of mouse myeloid leukemia cells.

The differentiated functions of phagocytosis, locomotion, and morphological changes into cells resembling granulocytes and macrophages were induced in cultured mouse myeloid leukemic cells, M1 clone 34, by treatment with human saliva. The rates of induction of these differentiated phenotypes were proportional to the concentration of saliva added and the period of treatment. The factor inducing differentiation was nondialyzable and heat labile. This factor was purified 70-fold by fractionation with Diaflo membranes and DE52 column chromatography. The activities inducing the three differentiated characters examined were purified together, suggesting that they were all due to the same factor.