Stimulation of hemopoietic colony formation from mouse marrow cells in vitro using human dialyzable leukocyte...

The influence of dialyzable extract from human leukocytes (DLE) on the in vitro growth of the granulocyte-macrophage colony-forming cell (GM-CFC) colonies from progenitors of mouse bone marrow cells was studied. DLE alone did not induce the colony growth but it modulated the number of colonies if administered together with a colony-stimulating factor (CSF). The costimulatory effect prevailed in a broad range of DLE dilution and the index of increase was enhanced with the lowering of the CSF concentration. The costimulatory augmentation of clonal proliferation of GM-CFC with DLE was further strengthened by addition of indomethacin, thus indicating an intervening role of prostaglandins in the modulatory influence of DLE.