title: Characterization of the inducer required for the development of macrophage and granulocyte colonies.
abstract: A substance produced by various types of cells can induce from single hematopoietic cells the formation of colonies of normal macrophages and granulocytes. This inducer has been purified 600-fold from serum-free conditioned medium from a tissue culture line of mouse cells. It is shown that the inducer is a protein, with a molecular weight of 65-70,000, whose inducing activity was about 1 ng per colony. Acrylamide gel electrophoresis of this material gave four bands, only one of which contained inducing activity. The purified protein was inactive. Activity was regained by the addition of a low molecular weight cofactor that is present in conditioned medium. Under certain conditions, activity was also regained by the addition of adenosine 3':5'-cyclic monophosphate (cyclic AMP).
mesh_terms: D000818:Animals; D001681:Biological Assay; D001769:Blood; D002417:Cattle; D002455:Cell Division; D002478:Cells, Cultured; D002499:Centrifugation, Density Gradient; D002848:Chromatography, DEAE-Cellulose; D000242:Cyclic AMP / Q000494:pharmacology; D004589:Electrophoresis, Disc; D005374:Filtration; D006133:Growth Substances / Q000032:analysis* / Q000302:isolation & purification; D006412:Hematopoietic Stem Cells; D006736:Horses; D007962:Leukocytes; D008264:Macrophages; D051379:Mice; D008970:Molecular Weight; D011506:Proteins / Q000032:analysis* / Q000302:isolation & purification
chemical_list: D006133:Growth Substances; D011506:Proteins; D000242:Cyclic AMP