title: Activation of human monocytes by interleukin 2: role of T lymphocytes.
abstract: The effect of interleukin 2 (IL2) on the capability of human monocytes to secrete reactive oxygen species triggered via Fc-gamma receptor (Fc-gamma R) function had been investigated by measurement of chemiluminescence (CL). IL 2 did not activate highly purified (hp) monocytes to respond to Fc-gamma R mediated phagocytic stimulation with an enhanced respiratory burst activity unless low numbers of T cells had been co-cultured with hp monocytes. Supernatants from IL 2 treated PBMC contained interferon-gamma (IFN-gamma) and monocyte activating factor (MAF) activity. The secretion of both cytokine activities was strongly enhanced by cooperative function of monocytes. The correlation of IL 2 induced secretion of IFN-gamma and MAF activity was striking, however, monoclonal antibody (mAb) anti-human IFN-gamma failed to abrogate IL 2 stimulated and lymphocyte dependent monocyte activation. Although IL 2 had no direct monocyte activating effect, pretreatment of hp monocytes with IL 2 led to monocyte priming: subsequent co-culture with autologous control T cells enhanced the monocyte Fc-gamma R mediated CL response. The priming of monocytes by IL 2 was dependent on the interaction of IL 2 with the monocytic IL 2 receptor as shown by inhibition experiments with anti IL 2 R monoclonal antibody. Thus the IL 2 driven monocyte/T-cell interaction leads to an increased Fc-gamma R mediated monocytic respiratory burst activity and to the secretion of a soluble MAF activity, but there were no detectable amounts of IFN-gamma.
authors.affiliation: Forschungsinstitut Borstel, Department of Immunology and Cell Biology, FRG.
authors.forename: J
authors.initials: J
authors.lastname: Ennen
authors.forename: M
authors.initials: M
authors.lastname: Ernst
authors.forename: H D
authors.initials: HD
authors.lastname: Flad
mesh_terms: D000911:Antibodies, Monoclonal; D000943:Antigens, Differentiation / Q000276:immunology; D001685:Biological Factors / Q000378:metabolism; D002450:Cell Communication / Q000276:immunology; D006801:Humans; D066298:In Vitro Techniques; D007371:Interferon-gamma / Q000378:metabolism; D007376:Interleukin-2 / Q000494:pharmacology*; D008163:Luminescent Measurements; D009000:Monocytes / Q000276:immunology*; D011961:Receptors, Fc / Q000276:immunology; D017452:Receptors, IgG; D015375:Receptors, Interleukin-2 / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D000943:Antigens, Differentiation; D001685:Biological Factors; D007376:Interleukin-2; D011961:Receptors, Fc; D017452:Receptors, IgG; D015375:Receptors, Interleukin-2; D007371:Interferon-gamma