蛋白性分化诱导因子(DIF)对体外培养的人骨髓白血病细胞的分化诱导作用正日益受到瞩目。过去虽已知道,在致有丝分裂原刺激的淋巴细胞培养上清中存在DIF,但由于不能完全精制DIF,故对其性状并不明确。最近作者从大量末梢血单核细胞培养上清中精制了DIF,明确它是一种肿瘤坏死因子(TNF)。由致有丝分裂原刺激的单核细胞培养上清所含有的γ干扰素(IFN-γ)对骨髓性和单核性白血病细胞有分化诱导作用,但究竟是诱导还是促进作用并不明确,因为即使采用亲和层析法除去IFN-γ后,仍然存在强的分化诱导活性。从这种除去IFN-γ的培养物精制DIF。以急性骨髓性白血病病人末梢血建立的ML-1细胞作为靶细胞,以NBT还原能力作为分化指标,采用各种层析法进行精制,然后用SDS凝 The differentiation induction of protein differentiation inducing factor (DIF) on human myeloid leukemia cells in vitro is attracting more and more attention. Although it has been known in the past that DIF exists in the mitosis-stimulated lymphocyte culture supernatant, its trait is not known because DIF can not be completely purified. Recently, the author purified DIF from a large number of peripheral blood mononuclear cell culture supernatants, making it clear that it is a tumor necrosis factor (TNF). The interferon gamma (IFN-γ) contained in mitogen-stimulated monocyte-cell culture supernatants has differentiation-inducing effects on myeloid and monocytic leukemia cells, but it is not clear whether or not the induction or promotion is effective After the removal of IFN-γ by affinity chromatography, strong differentiation-inducing activity still exists. DIF was purified from this IFN-γ-depleted culture. ML-1 cells established from peripheral blood of patients with acute myeloid leukemia were used as target cells, NBT reducing ability was taken as a differentiation index, and purified by various chromatographic methods, followed by SDS coagulation