title: Interleukin-6 synergizes with M-CSF in the formation of macrophage colonies from purified human marrow progenitor cells.
abstract: We examined the in vitro stimulative effects of recombinant human interleukin-6 (IL-6, or interferon-beta 2) on purified human bone marrow progenitor cells. IL-6 alone or in combination with erythropoietin (Epo), IL-3, GM-CSF, or G-CSF did not induce colony formation. However, IL-6 strongly synergized with M-CSF in stimulating macrophage colony formation (colony numbers and size). The magnitude of IL-6 synergism with M-CSF was dose dependent; maximal potentiation of M-colony formation was evident at approximately 100 to 1,000 U/mL IL-6. When the addition of IL-6 to M-CSF-supplemented cultures was delayed for more than one day after the beginning of culture, enhancement of macrophage colony formation was lost. IL-6 stimulation of M-CSF-responsive colony formation was not apparent when nonpurified marrow cells were plated, most likely due to endogenous IL-6 release. These observations suggest that IL-6, in addition to playing a role in B-lymphocyte proliferation can potentiate the human immune defence mechanism by stimulating monocyte-macrophage development as well.
authors.affiliation: Dr Daniel den Hoed Cancer Center, Rotterdam, The Netherlands.
authors.forename: F J
authors.initials: FJ
authors.lastname: Bot
authors.forename: L
authors.initials: L
authors.lastname: van Eijk
authors.forename: L
authors.initials: L
authors.lastname: Broeders
authors.forename: L A
authors.initials: LA
authors.lastname: Aarden
authors.forename: B
authors.initials: B
authors.lastname: Löwenberg
mesh_terms: D000328:Adult; D001853:Bone Marrow / Q000502:physiology*; D002450:Cell Communication / Q000187:drug effects; D003114:Colony-Forming Units Assay; D003115:Colony-Stimulating Factors / Q000494:pharmacology*; D004357:Drug Synergism; D004921:Erythropoietin / Q000494:pharmacology; D006410:Hematopoiesis / Q000187:drug effects*; D006412:Hematopoietic Stem Cells / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D015850:Interleukin-6; D007378:Interleukins / Q000494:pharmacology*; D016173:Macrophage Colony-Stimulating Factor; D008264:Macrophages / Q000187:drug effects* / Q000502:physiology
chemical_list: D003115:Colony-Stimulating Factors; D015850:Interleukin-6; D007378:Interleukins; D004921:Erythropoietin; D016173:Macrophage Colony-Stimulating Factor