title: Erythroid progenitor cells (CFU-E*) from Friend virus-infected mice undergo 55Fe suicide in vitro in the absence of added erythropoietin.
abstract: We have investigated the effect of 55Fe on the survival in suspension of erythropoietin (epo)-independent erythroid progenitor cells (CFU-E*) induced by Friend polycythemia virus (FV). Spleen cells from C3Hf/Bi mice previously infected with FV were exposed to carrier-free 55Fe, and the survival of CFU-E* as a function of time in liquid medium was determined from the number of erythroid colonies that developed from these cells seeded in plasma cultures without added epo. The results showed that spleen CFU-E* were highly vulnerable to 55Fe: Do approximately equal to 1 h exposure to 100 microCi/ml. Marrow CFU-E* behaved in a similar manner. The 55Fe responsible for their suicide had been presented to the progenitor cells only during the 4-h period of incubation, after which they were washed and plated in excess nonradioactive iron. We therefore conclude that CFU-E* themselves, and not only their progeny, are capable of actively incorporating iron. Under the same conditions in the absence of added epo, the effect of 55Fe on the survival of normal spleen or marrow CFU-E could not be assessed because two few normal CFU-E survived the incubation period. Normal bone marrow cells incubated in complete medium containing epo retained their capacity for erythrocytic colony formation, and CFU-E could then be shown to be vulnerable to 55Fe. Thus, either the iron-incorporating system of normal CFU-E was inducible by epo, or else epo permitted survival of the CFU-E so that the activity of a constitutive iron-incorporating system could be recognized.
mesh_terms: D000818:Animals; D001853:Bone Marrow / Q000473:pathology; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D004921:Erythropoietin / Q000494:pharmacology*; D005260:Female; D005622:Friend murine leukemia virus / Q000472:pathogenicity; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000528:radiation effects; D007501:Iron / Q000633:toxicity*; D007504:Iron Radioisotopes; D007942:Leukemia, Experimental / Q000473:pathology*; D008297:Male; D051379:Mice; D008809:Mice, Inbred C3H; D013154:Spleen / Q000473:pathology
chemical_list: D007504:Iron Radioisotopes; D004921:Erythropoietin; D007501:Iron