INTERLEUKIN-6 SYNERGIZES WITH M-CSF IN THE FORMATION OF MACROPHAGE COLONIES FROM PURIFIED HUMAN MARROW PROGENITOR CELLS

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  • 1 February 1989
    • journal article
    • research article
    • Vol. 73  (2) , 435-437
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 .apprx. 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.