POSITIVE AND NEGATIVE EFFECTS OF TUMOR NECROSIS FACTOR ON COLONY GROWTH FROM HIGHLY PURIFIED NORMAL MARROW PROGENITORS

The effects of recombinant human tumor necrosis factor alpha (TNFα) on colony growth were studied using highly enriched progenitor cells from normal human bone marrow. Supplementation of TNF to culture resulted in a dose-dependent suppression of granulocyte colony-stimulating factor (G-CSF) induced granulocytic colony formation and also erythropoietin (Epo) induced erythroid burst formation. However, the number of erythroid bursts, stimulated by interleukin-3 (IL-3) plus Epo, increased when TNF was added at comparable concentration.