[Basic studies on colony formation of erythroid progenitor cells]

Fundamental studies on CFU-E colony formation were done using bone marrow cells of mice by the methylcellulose culture method. The number of CFU-E colonies reached a peak after 48 hours of incubation. A linear relationship was observed between the number of CFU-E colonies and the number of inoculated bone marrow cells. The number of CFU-E colonies increased dependently on the concentration of erythropoietin (Epo) and reached almost a plateau above 0.25 U/ml. There was little difference in the CFU-E colony forming activity of the two sources of Epo (one partially purified from human urine at our laboratory and the other obtained from Connaught Laboratories Ltd. as Step III derived from plasma of anemic sheep). There was little difference in the number of marrow CFU-E of two strains of mice (ddY and BDF1). The best conditions in the concentration of culture medium were 10-30% in FCS, 0.5-1.0% in BSA, 10(-4) M in 2-mercaptoethanol, respectively. These observations are thought to be useful for the development of studies on CFU-E.