title: Staphylococcus aureus enterotoxins A and B inhibit human and mice eosinophil chemotaxis and adhesion in vitro.
abstract: Staphylococcus aureus aggravates the allergic eosinophilic inflammation. We hypothesized that Staphylococcus aureus-derived enterotoxins directly affect eosinophil functions. Therefore, this study investigated the effects of Staphylococcal enterotoxins A and B (SEA and SEB) on human and mice eosinophil chemotaxis and adhesion in vitro, focusing on p38 MAPK phosphorylation and intracellular Ca(2+) mobilization. Eosinophil chemotaxis was evaluated using a microchemotaxis chamber, whereas adhesion was performed in VCAM-1 and ICAM-1-coated plates. Measurement of p38 MAPK phosphorylation and intracellular Ca(2+) levels were monitored by flow cytometry and fluorogenic calcium-binding dye, respectively. Prior incubation (30 to 240 min) of human blood eosinophils with SEA (0.5 to 3 ng/ml) significantly reduced eotaxin-, PAF- and RANTES-induced chemotaxis (P<0.05). Likewise, SEB (1 ng/ml, 30 min) significantly reduced eotaxin-induced human eosinophil chemotaxis (P<0.05). The reduction of eotaxin-induced human eosinophil chemotaxis by SEA and SEB was prevented by anti-MHC monoclonal antibody (1 μg/ml). In addition, SEA and SEB nearly suppressed the eotaxin-induced human eosinophil adhesion in ICAM-1- and VCAM-1-coated plates. SEA and SEB prevented the increases of p38 MAPK phosphorylation and Ca(2+) levels in eotaxin-activated human eosinophils. In separate protocols, we evaluated the effects of SEA on chemotaxis and adhesion of eosinophils obtained from mice bone marrow. SEA (10 ng/ml) significantly reduced the eotaxin-induced chemotaxis along with cell adhesion to both ICAM-1 and VCAM-1-coated plates (P<0.05). In conclusion, the inhibition by SEA and SEB of eosinophil functions (chemotaxis and adhesion) are associated with reductions of p38 MAPK phosphorylation and intracellular Ca(2+) mobilization.
authors.affiliation: Department of Pharmacology, Faculty of Medical Sciences, University of Campinas (UNICAMP), São Paulo, Brazil.
authors.forename: Dalize M
authors.initials: DM
authors.lastname: Squebola-Cola
authors.affiliation: Department of Pharmacology, Faculty of Medical Sciences, University of Campinas (UNICAMP), São Paulo, Brazil.
authors.forename: Glaucia C
authors.initials: GC
authors.lastname: De Mello
authors.affiliation: Department of Pharmacology, Faculty of Medical Sciences, University of Campinas (UNICAMP), São Paulo, Brazil.
authors.forename: Gabriel F
authors.initials: GF
authors.lastname: Anhê
authors.affiliation: Department of Immunology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil.
authors.forename: Antonio
authors.initials: A
authors.lastname: Condino-Neto
authors.affiliation: Department of Biology and Physiology, Faculty of Medicine of Jundiai (FMJ), São Paulo, Brazil.
authors.forename: Ivani A
authors.initials: IA
authors.lastname: DeSouza
authors.affiliation: Department of Pharmacology, Faculty of Medical Sciences, University of Campinas (UNICAMP), São Paulo, Brazil. Electronic address: edson.antunes@uol.com.br.
authors.forename: Edson
authors.initials: E
authors.lastname: Antunes
mesh_terms: D000818:Animals; D020013:Calcium Signaling / Q000187:drug effects; D002448:Cell Adhesion / Q000187:drug effects / Q000276:immunology; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D002633:Chemotaxis / Q000187:drug effects* / Q000276:immunology; D004768:Enterotoxins / Q000633:toxicity*; D004804:Eosinophils / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D005434:Flow Cytometry; D006801:Humans; D020935:MAP Kinase Signaling System / Q000187:drug effects; D051379:Mice; D013997:Time Factors
chemical_list: D004768:Enterotoxins; C026066:enterotoxin A, Staphylococcal; C031818:enterotoxin B, staphylococcal
keywords: Eotaxin; ICAM-1; Infection; MHC; VCAM-1; p38 mitogen-activated protein kinase