Effects of recombinant growth factors on radiation survival of human bone marrow progenitor cells.

The purpose of this study was to evaluate the individual radioprotective effects of 4 distinct purified recombinant human hematopoietic growth factors, namely recombinant human granulocyte-macrophage colony stimulating factor (rGM-CSF), recombinant human granulocyte colony stimulating factor (rG-CSF), recombinant human interleukin 1 (rIL-1), and recombinant human interleukin 2 (rIL-2) on human myeloid (CFU-GM) and erythroid (BFU-E) bone marrow progenitor cells. We demonstrate that (a) preconditioning with rGM-CSF, rG-CSF, or rIL-1 enables CFU-GM to repair sublethal radiation damage and renders CFU-GM less radiosensitive, (b) preconditioning with rGM-CSF or rIL-1 enables BFU-E to repair sublethal radiation damage, and (c) preconditioning with rIL-2 does not increase the radiation survival of CFU-GM or BFU-E. The effects of recombinant growth factors, in particular rGM-CSF, on the radiation damage repair, radiosensitivity, and proliferative activity of bone marrow progenitor cells resulted in a substantial increase in the mean numbers of progenitor cell-derived hematopoietic colonies in irradiated marrow samples. The effects of rGM-CSF on the radiation response of CFU-GM and BFU-E, and the effects of rG-CSF as well as rIL-1 on the radiation response of CFU-GM did not appear to require the presence of T-cells/T-cell precursors, NK-cells, B-cells/B-cell precursors, monocytes, macrophages, MY8 antigen positive non-CFU-GM myeloblasts, promyelocytes, myelocytes, metamyelocytes, granulocytes, or glycophorin A positive erythroid cells since virtually identical results were obtained with unsorted marrow samples or highly purified fluorescence activated cell sorter (FACS) isolated progenitor cell suspensions. To our knowledge, this report represents the first study on recombinant human growth factor-induced modulation of the radiation responses of normal human bone marrow progenitor cells.