Figure 3.
Erythropoietin responsiveness of SOCS3−/− erythroid progenitor cells. (a and b) Data from two independent experiments are shown. E11.5 fetal liver cells (5 × 103) were cultured for 3 days in various concentrations of erythropoietin. Individual results represent means of duplicate cultures, normalized for CFU-E number in supramaximal concentrations of erythropoietin (2 units/ml). The numbers of CFU-E in cultures containing maximal concentrations of erythropoietin ranged between 264 and 684. (c) E11.5 fetal liver cells (104) were cultured for 7 days in triplicate in stem cell factor, IL-3, and various final concentrations of erythropoietin, and the number of BFU-E (including mix-CFC) enumerated as above. The numbers of BFU-E in cultures containing maximal concentrations of erythropoietin ranged between 26 and 50.