title: The role of phagocytic cells in human blood leukocyte suspensions for in vitro colony-forming cells.
abstract: The iron ingestion method was used to separate colony stimulating cells from in vitro colony forming cells (CFU-C) in human white blood cell (WBC) suspensions. The depletion of phagocytic cells (granulocytes and monocytes) from WBC eliminated spontaneous colony growth, without influencing the total number of CFU-C. Thus, phagocyte-free human WBC can be used as a target for measuring human colony stimulating activity (CSA). Such leukocytes can be cryopreserved, thus making possible the use of standardized target cell preparations for longitudinal studies. Hemolysate added to phagocyte-free blood leukocytes did not induce colony formation but could enhance it in the presence of a suitable CSA. Spontaneous colony formation of unseparated WBC was significantly reduced by selective destruction of granulocytes by freezing in 10% DMSO, thus indicating that both granulocytes and monocytes are involved in the production of endogenous CSA in WBC suspensions.
mesh_terms: D002455:Cell Division / Q000187:drug effects; D002469:Cell Separation; D002478:Cells, Cultured; D002999:Clone Cells; D003470:Culture Media; D005615:Freezing; D006098:Granulocytes / Q000276:immunology; D006801:Humans; D007501:Iron / Q000494:pharmacology; D007962:Leukocytes / Q000276:immunology* / Q000528:radiation effects; D009000:Monocytes / Q000276:immunology; D010586:Phagocytes / Q000276:immunology*
chemical_list: D003470:Culture Media; D007501:Iron