title: Phagocytosis of Giardia lamblia trophozoites by cytokine-activated macrophages.
abstract: Phagocytosis of Giardia lamblia trophozoites by cytokine-activated and non-activated bone marrow-derived macrophages was examined in vitro. Macrophages treated with recombinant interferon-gamma (IFN-gamma) and bacterial lipopolysaccharide (LPS) ingested a significantly higher number of in vitro-grown trophozoites than untreated macrophages. Maximal uptake of parasites occurred after 4 h and 6 h of incubation where 81.4% and 79.1% of macrophages were positive for trophozoites. Other cytokines tested, IL-2, IL-3, IL-4, IL-5, GM-CSF, CSF-1 and tumour necrosis factor-alpha (TNF-alpha) either alone or in combination with LPS, failed to activate macrophages to phagocytose G. lamblia. The induction of this activated macrophage anti-microbial function was achieved pharmacologically using phorbol myristate acetate (PMA) and ionophore A23187. The giardicidal activity of macrophages activated with IFN-gamma and LPS or that induced by PMA and A23187 was inhibited by H-7, indicating the role for protein kinase C in the intracellular events following activation.
authors.affiliation: Department of Zoology, University of Alberta, Edmonton, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Belosevic
authors.forename: C W
authors.initials: CW
authors.lastname: Daniels
mesh_terms: D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D000818:Animals; D001854:Bone Marrow Cells; D000001:Calcimycin / Q000494:pharmacology; D002478:Cells, Cultured; D016207:Cytokines / Q000494:pharmacology*; D016829:Giardia lamblia / Q000276:immunology*; D066298:In Vitro Techniques; D007371:Interferon-gamma / Q000494:pharmacology; D007546:Isoquinolines / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000276:immunology; D008262:Macrophage Activation / Q000187:drug effects; D008264:Macrophages / Q000276:immunology*; D051379:Mice; D008809:Mice, Inbred C3H; D010587:Phagocytosis; D010879:Piperazines / Q000494:pharmacology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D011994:Recombinant Proteins; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: D016207:Cytokines; D007546:Isoquinolines; D008070:Lipopolysaccharides; D010879:Piperazines; D011994:Recombinant Proteins; D000001:Calcimycin; D007371:Interferon-gamma; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate