Purification of erythropoietin-responsive cells by immune hemolysis

Immature erythroid cell precursors from 12- and 13-day fetal mouse livers were concentrated by differential antibody-mediated hemolysis. The effect of erythropoietin on these purified erythroid cell precursors was studied in vitro. Addition of erythropoietin stimulates erythroid cells to proliferate, and to differentiate to cells that actively synthesize hemoglobin. This erythropoietin-induced erythropoiesis is sustained in culture for at least 48 hr.