Effects of recombinant tumor necrosis factor on proliferation and differentiation of leukemic and normal hemopoietic cells in vitro. Relationship to cell surface receptor.

The clonogenic growth of myeloid leukemia cell lines was inhibited by recombinant tumor necrosis factor (rTNF) at 1-15 pM concentration. However, wild type (promyelocytic) HL-60 cells were highly resistant to growth inhibition, but responded with differentiation into monocyte-like cells at 100 pM rTNF. The clonogenic growth of fresh acute myeloid leukemia cells was inhibited by 50% at approximately 15 pM rTNF. The growth of normal granulocyte-macrophage progenitors (CFU-GM) was also inhibited (by 50 pM rTNF), as was the growth of erythroid progenitors (BFU-E) (by 150 pM rTNF). A synergistic antiproliferative effect was demonstrated between rTNF and recombinant interferon-gamma. Use of radioiodinated rTNF enabled us to detect 1,500-2,100 binding sites on myeloid cell lines at 4 degrees C with Kd of approximately 300 pM. At 37 degrees C, the transfer of bound ligand to lysosomes was followed by degradation, inhibited by NH4+. No correlation was observed between the number of binding sites or affinity at 4 degrees C and antiproliferative response to the addition of rTNF.