PRODUCTION OF ERYTHROID POTENTIATING FACTOR(S) BY A HUMAN MONOCYTIC CELL-LINE

  • 1 January 1981
    • journal article
    • research article
    • Vol. 57  (1) , 170-173
Abstract
U-937 is a human monocytic cell line that elaborates factors that affect normal human hematopoiesis in vitro. Studies on the factor effects demonstrated an erythroid potentiating factor (EPF) and a potent inhibitor of granulocyte-macrophage (CFU-GM) colony growth. The EPF was present in both serum-containing and serum-free U-937 conditioned media, had a dose-dependent erythroid colony formation effect and was remarkably heat stable. The CFU-GM inhibitory activity was detected in serum-free conditioned medium, was dose-dependent and heat labile and its effect was reversed by indomethacin. Indomethacin did not alter the erythroid effects of the U-937 conditioned medium. No colony stimulating factor (CSF) or erythropoietin could be detected in this medium. The existence of a human cell line capable of producing EPF without simultaneous CSF production will permit further studies on the biochemical and biologic nature of these factors.