Recombinant human macrophage colony-stimulating factor (M-CSF) requires subliminal concentrations of granulocyte/macrophage (GM)-CSF for optimal stimulation of human macrophage colony formation in vitro.
Human macrophage colony-stimulating factor (M-CSF or CSF-1), either in purified or in recombinant form, is able to generate macrophagic colonies in a murine bone marrow colony assay, but only stimulates small macrophagic colonies of 40-50 cells in a human bone marrow colony assay. We report here that recombinant human granulocytic/macrophage colony stimulating factor (rhGM-CSF) at concentrations in the range of picograms enhances the responsiveness of bone marrow progenitors to M-CSF activity, resulting in an increased number of macrophagic colonies of up to 300 cells. Polyclonal antiserum against M-CSF did not alter colony formation of bone marrow progenitors incubated with GM-CSF at optimal concentration (1-10 ng/ml) for these in vitro assays. Thus, GM-CSF at higher concentrations (nanogram range) can by itself, elicit macrophagic colonies, and at lower concentrations (picogram range) acts to enhance the responsiveness of these progenitors to M-CSF.
D000818:Animals; D002478:Cells, Cultured; D003114:Colony-Forming Units Assay; D003115:Colony-Stimulating Factors / Q000008:administration & dosage* / Q000494:pharmacology; D004357:Drug Synergism; D016179:Granulocyte Colony-Stimulating Factor; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D006133:Growth Substances / Q000008:administration & dosage*; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology; D007377:Interleukin-3 / Q000494:pharmacology; D008264:Macrophages / Q000502:physiology*; D051379:Mice; D011994:Recombinant Proteins / Q000494:pharmacology
D003115:Colony-Stimulating Factors; D006133:Growth Substances; D007375:Interleukin-1; D007377:Interleukin-3; D011994:Recombinant Proteins; D016179:Granulocyte Colony-Stimulating Factor; D016178:Granulocyte-Macrophage Colony-Stimulating Factor