Effects of erythroid differentiation factor (EDF) on proliferation and differentiation of human hematopoietic progenitors.

The effects of erythroid differentiation factor (EDF) on normal human hematopoietic progenitor cells were examined by bone marrow colony assay. Addition of EDF to the erythroid colony assay system enhanced erythroid burst-forming unit (BFU-E)-derived colony formation, and this effect disappeared on removal of adherent cells. Conditioned medium of EDF-treated monocytes also enhanced BFU-E colony formation, whereas conditioned medium of EDF-treated T cells did not. In contrast, EDF inhibited erythroid colony-forming unit (CFU-E) colony formation dose-dependently, although it had no effect on colony formation by myeloid cells. These data show that EDF has a specific effect on human hematopoietic progenitors of the erythroid lineage. The results also indicate that EDF enhanced BFU-E colony formation by stimulating adherent cells to produce factors with burst-promoting activity (BPA), but suppressed CFU-E colony formation by promoting differentiation of these cells.