[Stimulation of the growth of murine bone marrow colonies in vitro by an acute inflammatory exudate. Comparison with colony stimulating factor CSF)].

Formation of colonies from mice bone marrow progenitors of macrophages and granulocytes in methylcellulose culture was induced by an inflammatory pleural exudate obtained from mice injected with dextran. Mitogenic activity of this acute inflammatory exudate was compared with that of colony stimulating factor (CSF). It was found that colony and cluster counts, during 10 days of culture, were similar with the two types of stimulating factors. When used at the same dose, exudate was less active than CSF. It was concluded that inflammatory exudate showed an activity similar to that of CSF but contained a smaller amount of stimulating factor. Further cytochemical studies are necessary to specify whether or not the two factors induced the same type of colonies (monocytic or granulocytic).