EVIDENCE FOR PROLIFERATION OF ERYTHROID PROGENITOR CELLS IN THE ABSENCE OF ADDED ERYTHROPOIETIN

Abstract

The cellular mechanisms underlying the requirement of leukocyte conditioned medium for human erythroid colony formation was studied. Using photographic methods, erythroid progenitor cells were shown to form small colonies in the absence of added erythropoietin (epo). The addition of epo at this time led to further growth and hemoglobinization of cells within the colony. Leukocyte conditioned medium was required for this early proliferative stage of erythroid colony formation.