Biochemical properties of differentiation factors for murine myelomonocytic leukemic cells in organ conditioned media — separation from colony‐stimulating factors

Abstract

A number of different organs and tissues from untreated or endotoxin‐injected mice were surveyed for their ability to produce conditioned medium that could induce differentiation of the myelomonocytic leukemic cell line WEHI‐3B. All organs were able to do this but were much more effective from endotoxin‐injected animals. Production of the differentiation factor (DF) was dependent on protein synthesis and occurred throughout the 7‐day incubation period. DF produced by the different organs in vitro and found in vivo in endotoxin serum were indistinguishable from each other by several fractionation procedures but could be distinguished from the majority of granulocyte‐macrophage and macrophage ..