Contrasting effect of IFN-γ and IFN-α/gb on differentiation of some clones of mouse myeloid leukemic cells

Abstract

Mouse myeloid leukemic M1 cells are induced to differentiate into macrophage-like cells by a differentiation-inducing factor (D-factor) and various agents. IFN-γ alone did not induced differentiation of clone T22-3 of M1 cells but inhibited their differentiation by D-factor. That is, IFN-γ at 4 U/ml inhibited 50% of phagocytic activity of T22-3 cells induced by 7 × 10 −11 M D-factor. In addition, it inhibited the induction of lysozyme activity and morphological differentiation of these cells by D-factor. IFN-γ also inhibited dexamethasone-induced differentiation of T22-3 cells. Previously interferon-α/β was shown not to induce differentiation of M1 cells itself, but to enhance induction of their differentiation by D-factor. The present study showed that IF-α/gb and IFN-γ had opposite effects on induction of differentiation of T22-3 cells by D-factor. The effect of IFN-γ on the differentiation of M1 cells varied with the clone of M1 cells used: IFN-γ inhibited D-factor-induced differentiation of cells of clones T22-3 and S2, but induced differentiation of cells of clones B24 and S1.