title: Evidence suggesting a stimulatory role for interleukin-10 in erythropoiesis in vitro.
abstract: Interleukin-10 (IL-10) has been shown to exert anti-inflammatory effects by suppressing macrophage proliferation and inhibiting cytokine production. In this study we show that in the presence of erythropoietin (EPO), the addition of IL-10 results in a significant dose-dependent increase in both Burst Forming Unit-Erythroid (BFU-E) and Colony Forming Unit-Erythroid (CFU-E) colony growth in both serum-containing and serum-free murine cultures in vitro. IL-10 acts at the later stages of erythroid cell proliferation and differentiation as the increase in colony number was greater in CFU-E than in BFU-E, and was similar when IL-10 was added to BFU-E cultures at the time of culture initiation as when its addition to culture was delayed for 7 days. Furthermore, no increase in BFU-E colony number was noted when IL-10, added at the time of culture initiation, was neutralized by the addition to culture of a monoclonal anti-IL-10 antibody up to 7 days later. The increases in BFU-E by IL-10 addition were not the result of prolongation of BFU-E colony lifespan, which was not significantly different in IL-10 treated and control cultures, respectively. Rather IL-10 stimulated the proliferation of erythroid clusters that were now large enough to be recognized as colonies. IL-10-induced stimulation of erythropoiesis appeared to be independent of its inhibitory effects on macrophage function, as stimulation of erythroid colony growth was similar in macrophage-containing and depleted cultures. Studies to determine if the IL-10 effect was direct or indirect yielded equivocal results. A limiting dilution assay suggested a direct effect. However, a log/log dose response curve with IL-10 did not pass through the origin suggesting an indirect effect. These studies indicate that IL-10 acts synergistically with EPO to significantly increase stimulation of erythroid differentiation and proliferation in vitro and may be involved in the regulation of normal erythropoiesis in vivo.
authors.affiliation: Geriatric Research, Education and Clinical Center (GRECC), John L. McClellan Memorial Veterans Hospital, Little Rock, Arkansas 72205, USA.
authors.forename: C Q
authors.initials: CQ
authors.lastname: Wang
authors.forename: K B
authors.initials: KB
authors.lastname: Udupa
authors.forename: D A
authors.initials: DA
authors.lastname: Lipschitz
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D015672:Erythroid Precursor Cells / Q000166:cytology / Q000187:drug effects; D004920:Erythropoiesis / Q000187:drug effects*; D004921:Erythropoietin / Q000494:pharmacology*; D005260:Female; D016753:Interleukin-10 / Q000494:pharmacology*; D008264:Macrophages / Q000187:drug effects / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL
chemical_list: D004921:Erythropoietin; D016753:Interleukin-10