title: Interleukin-13 induces human monocyte/macrophage fusion and macrophage mannose receptor expression.
abstract: Inasmuch as we recently demonstrated that IL-4 is a strong inducer of monocyte/macrophage fusion and IL-13 has been observed to mimic many of the biologic effects of IL-4, the ability of IL-13 to promote human macrophage fusion in vitro was tested and compared with IL-4-mediated fusion. IL-13 induced the fusion of monocyte-derived macrophages as potently as IL-4 under identical culture conditions, and resulted in foreign body-type giant cell formation. At optimal concentrations of cytokine added, statistically equal numbers of macrophages participated in IL-13- and IL-4-induced fusion (66.1 +/- 4.6% and 63.9 +/- 4.4%, respectively). However, the effects of IL-13 and IL-4 were not additive or synergistic, and the maximum fusion obtained when both IL-4 and IL-13 were added was 63.8 +/- 3.6%. Only anti-human IL-13 Abs inhibited IL-13-induced foreign body giant cell formation; the fusion-inducing effects of IL-13 continued to be observed in the presence of neutralizing Abs to IL-4 and several other anti-cytokine Abs, including Abs against IFN-gamma, granulocyte-macrophage CSF, IL-3, and TNF-alpha. IL-13 also significantly enhanced the fluorescence intensity detected by anti-human macrophage mannose receptor Abs, indicating that IL-13, like IL-4, up-regulates expression of the receptor that may be an essential participant in macrophage fusion. The results of this study demonstrate that IL-13, like IL-4, is a potent human macrophage fusion factor, and suggest that although IL-13 acts independently of IL-4 to promote foreign body giant cell formation, it may trigger a common mechanism for macrophage fusion.
authors.affiliation: Institute of Pathology, Case Western Reserve University, Cleveland, OH 44106, USA.
authors.forename: K M
authors.initials: KM
authors.lastname: DeFife
authors.forename: C R
authors.initials: CR
authors.lastname: Jenney
authors.forename: A K
authors.initials: AK
authors.lastname: McNally
authors.forename: E
authors.initials: E
authors.lastname: Colton
authors.forename: J M
authors.initials: JM
authors.lastname: Anderson
mesh_terms: D002459:Cell Fusion / Q000187:drug effects; D019084:Fluorescent Antibody Technique, Indirect; D015726:Giant Cells / Q000187:drug effects / Q000502:physiology; D006801:Humans; D018793:Interleukin-13 / Q000494:pharmacology*; D015847:Interleukin-4 / Q000494:pharmacology; D037102:Lectins / Q000378:metabolism*; D037181:Lectins, C-Type; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology*; D008358:Mannose / Q000378:metabolism; D000090323:Mannose Receptor; D037241:Mannose-Binding Lectins; D009000:Monocytes / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology*; D011956:Receptors, Cell Surface / Q000096:biosynthesis* / Q000187:drug effects
chemical_list: D018793:Interleukin-13; D037102:Lectins; D037181:Lectins, C-Type; D000090323:Mannose Receptor; D037241:Mannose-Binding Lectins; D011956:Receptors, Cell Surface; D015847:Interleukin-4; D008358:Mannose