ENHANCEMENT OF THE GROWTH OF HUMAN EARLY ERYTHROID PROGENITORS BY BONE-MARROW CONDITIONED MEDIA

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  • 1 January 1980
    • journal article
    • research article
    • Vol. 8  (1) , 83-88
Abstract
The inclusion of condition media (CM) obtained from cultures of human bone marrow cells increased the number of erythroid bursts observed after a 14-day culture period. CM had no effect on the number of erythroid colonies observed at 5 days. The effect of CM on burst growth was more pronounced at limiting growth conditions, low serum or low erythropoietin (EPO) concentrations. Burst-forming units (BFUe) survived in culture and were able to respond to CM by increased colony growth and Hb synthesis as late as 8 days following the initiation of cultures. CM prevented the decline in the number of bursts observed in the absence of EPO during the first 4 days of culture; when EPO was added at later times, a decrease in burst formation was seen. Increased sensitivity of burst-forming cells to low concentrations of EPO and a reduced serum requirement were observed in cultures containing CM. The incorporation of 59Fe into heme was also increased by CM, giving a more sensitive test of CM activity than burst number. CM obtained from bone marrow cultures probably contains burst-promoting activity (BPA), one of the factors required for the proliferation of early erythroid progenitors.