title: Effect of isoproterenol and dexamethasone on the lipopolysaccharide induced expression of CD11b on bovine neutrophils.
abstract: The present experiments investigate the changes in expression of CD11b on bovine neutrophils and its modulation by isopropylnoradrenaline (IPN, isoproterenol), dexamethasone (DX), phenylephrine (alpha-agonist) and clenbuterol (beta-agonist). Both IPN and DX caused a dose-dependent inhibition of LPS-induced CD11b expression. A combination of IPN and DX elicited a synergistical decrease of the CD11b expression. Clenbuterol mimicked the effect of IPN, whereas phenylephrine did not. The effect of IPN and DX could at least partly be mediated through a decreased TNF-alpha production by monocytes since tumor necrosis factor-alpha (TNF-alpha) is shown to mediate a dose-dependent CD11b up-regulation. Stimulation of stress hormone receptors partly immuno-suppresses neutrophil functions by inhibition of CD11b expression on the neutrophil surface upon LPS stimulation. This inhibition is probably related to a decrease in TNF-alpha production. A similar mechanism of immuno-suppression could contribute to the higher susceptibility of cattle to Gram-negative bacterial infections of the udder and lung during periods of stress.
authors.affiliation: Department of Physiology, Biochemistry and Biometrics, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium.
authors.forename: A
authors.initials: A
authors.lastname: Diez-Fraile
authors.forename: E
authors.initials: E
authors.lastname: Meyer
authors.forename: A M
authors.initials: AM
authors.lastname: Massart-Leën
authors.forename: C
authors.initials: C
authors.lastname: Burvenich
mesh_terms: D000818:Animals; D002417:Cattle; D002469:Cell Separation / Q000662:veterinary; D003907:Dexamethasone / Q000494:pharmacology*; D005434:Flow Cytometry / Q000662:veterinary; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D016177:Macrophage-1 Antigen / Q000096:biosynthesis*; D009504:Neutrophils / Q000187:drug effects / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D015854:Up-Regulation
chemical_list: D008070:Lipopolysaccharides; D016177:Macrophage-1 Antigen; D014409:Tumor Necrosis Factor-alpha; D003907:Dexamethasone; D007545:Isoproterenol