title: IL-13 pre-treatment of murine peritoneal macrophages increases their anti-Toxoplasma gondii activity induced by lipopolysaccharides.
abstract: Th1 cytokines and microbial lipopolysaccharides (LPS) activate macrophages to produce inflammatory mediators and effector molecules. Althrough Th2 cytokines often have an opposite action to Th1 cytokines and down-modulate the inflammatory response of macrophages, they can induce a distinct alternative activation that is beneficial in host defence. In this study, we report that IL-13 enhances the anti-Toxoplasma activity of LPS-activated murine macrophages. The inhibition of parasite proliferation was not related to reduced Toxoplasma gondii penetration into the cells, nor to the conversion of tachyzoites into bradyzoites. Used alone, IL-13 triggers the polarisation of macrophages towards type 2. However, in LPS-activated macrophages, we show the priming capacity of this cytokine to enhance the expression of inducible nitric oxide synthase (iNOS), a major marker of type 1 macrophages. This effect of IL-13 was not dependent on the activation state of macrophages (resident versus thioglycolate-elicited) or the timing of pre-treatment. We demonstrate a correlation between the enhancement of NO production and upgrading of the microbicidal effectiveness of the macrophages. Thus, both Th2 and Th1 cytokines could activate macrophages to control infections.
authors.affiliation: Laboratoire des macrophages, Médiateurs de l'Inflammation et Interactions Cellulaires, Université Paul Sabatier Toulouse III, EA2405, INSERM IFR31 BP84225, 31432 Toulouse Cedex 4, France.
authors.forename: Hélène
authors.initials: H
authors.lastname: Authier
authors.forename: Sophie
authors.initials: S
authors.lastname: Cassaing
authors.forename: Valérie
authors.initials: V
authors.lastname: Bans
authors.forename: Philippe
authors.initials: P
authors.lastname: Batigne
authors.forename: Marie-Hélène
authors.initials: MH
authors.lastname: Bessières
authors.forename: Bernard
authors.initials: B
authors.lastname: Pipy
mesh_terms: D000818:Animals; D001119:Arginase / Q000032:analysis / Q000378:metabolism; D015153:Blotting, Western / Q000379:methods; D002478:Cells, Cultured; D018793:Interleukin-13 / Q000494:pharmacology*; D007411:Intestinal Diseases, Parasitic / Q000276:immunology*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008262:Macrophage Activation; D017737:Macrophages, Peritoneal / Q000187:drug effects* / Q000276:immunology; D051379:Mice; D009569:Nitric Oxide / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D014122:Toxoplasma; D014124:Toxoplasmosis, Animal / Q000276:immunology*; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology
chemical_list: D018793:Interleukin-13; D008070:Lipopolysaccharides; D014409:Tumor Necrosis Factor-alpha; D009569:Nitric Oxide; D052247:Nitric Oxide Synthase Type II; D001119:Arginase