title: Survival and repopulation of irradiated 'pre-CFU-c' in mice.
abstract: Supernatants of murine bone-marrow cultures contain a colony-promoting factor (CPF) which increases the number of granulocyte and macrophage colonies in semi-solid agar cultures in the presence of colony-stimulating factor (CSF). Incubation of bone-marrow cells with CPF results in an increase in the number of granulocyte/macrophage progenitor cells (CFU-c) and the CPF-responsive cells may be younger than the CFU-c. We have investigated the radiosensitivity and the pattern of the recovery after irradiation of CPF-responsive cells. We found that the radiosensitivity of CPF-responsive cells was significantly lower than those of CFU-c, burst-forming units-erythroid (BFU-e) and pluripotent stem cells in vivo (CFU-s) and in vitro (CFU-mix). The CPF-responsive cells remained subnormal even at 28 days after irradiation of the mice, a time when the CFU-s and CFU-c had recovered completely. Therefore the CPF-responsive cells may constitute a separate compartment, namely 'pre-CFU-c', in the maturation sequence of granulopoiesis, and this maturation of the 'pre-CFU-c' to CFU-c seems to be highly stimulated after irradiation to counterbalance the influx from CFU-s.
mesh_terms: D000818:Animals; D001853:Bone Marrow / Q000528:radiation effects*; D001854:Bone Marrow Cells; D002470:Cell Survival / Q000528:radiation effects; D003114:Colony-Forming Units Assay; D003115:Colony-Stimulating Factors / Q000494:pharmacology; D006098:Granulocytes / Q000502:physiology; D006410:Hematopoiesis / Q000528:radiation effects; D008264:Macrophages / Q000502:physiology; D051379:Mice; D014965:X-Rays
chemical_list: D003115:Colony-Stimulating Factors