Colony-stimulating factors active on human bone marrow cells from a Yoshida sarcoma cell line

Colony-stimulating factors (CSF) active on both human and murine bone marrow colony-forming units in culture (CFU-C) were found in the conditioned medium of Yoshida sarcoma cells (line YSSF-212T), although the cells originated from rats. The CSF were inactivated by digestion with trypsin, alpha-chymotrypsin, and pronase. By chromatography on DEAE-cellulose, the CSF were separated into five subgroups with different capacities to stimulate mouse granulocyte and macrophage progenitors. CSF in these five peaks were eluted from an Ultrogel AcA 44 gel filtration column with apparent molecular weights of 22,000– 25,000 daltons. CSF of nonhuman origin stimulating human CFU-C would be useful in hematologic studies of bone marrow cells.