title: Systemic release and protective role of IL-10 in staphylococcal enterotoxin B-induced shock in mice.
abstract: Staphylococcal enterotoxin B (SEB) is a bacterial superantigen that induces the production of several pro-inflammatory cytokines, leading to a self-limited shock. In the present study, we show that SEB also triggers the systemic release of IL-10, an anti-inflammatory and immunosuppressive cytokine. Serum IL-10 was undetectable (< 1000 pg/ml) in control BALB/c mice and rose to 8500 +/- 2850 pg/ml (mean +/- SEM) 4 h after injection of 100 micrograms SEB. Cell depletion experiments and analysis of IL-10 mRNA expression indicated that CD4+ cells played a major role in SEB-induced IL-10 production. Pretreatment of mice with neutralizing anti-IL-10 mAb before SEB challenge did not modify the release of TNF but led to increased and sustained IL-2 and IFN-gamma serum levels. Furthermore, although no lethality occurred in mice injected with SEB and control mAb, injection of anti-IL-10 mAb before SEB resulted in a 30% lethality (p < 0.05). This lethality was completely prevented by anti-IFN-gamma mAb injection, indicating that IFN-gamma plays a crucial role in the increased toxicity of SEB in anti-IL-10 mAb-injected mice. We conclude that SEB induces the production of IL-10 by CD4+ cells in vivo and that endogenous IL-10 plays an important immunoregulatory role in this model by down-regulating IL-2 and IFN-gamma production.
authors.affiliation: Multidisciplinary Laboratory of Biomedical Research, Free University of Brussels, Belgium.
authors.forename: S
authors.initials: S
authors.lastname: Florquin
authors.forename: Z
authors.initials: Z
authors.lastname: Amraoui
authors.forename: D
authors.initials: D
authors.lastname: Abramowicz
authors.forename: M
authors.initials: M
authors.lastname: Goldman
mesh_terms: D000818:Animals; D001483:Base Sequence; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D016207:Cytokines / Q000032:analysis; D004768:Enterotoxins; D007371:Interferon-gamma / Q000502:physiology; D016753:Interleukin-10 / Q000096:biosynthesis / Q000276:immunology / Q000502:physiology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction / Q000379:methods; D012333:RNA, Messenger / Q000032:analysis; D012772:Shock, Septic / Q000139:chemically induced / Q000276:immunology*
chemical_list: D016207:Cytokines; D004768:Enterotoxins; D012333:RNA, Messenger; D016753:Interleukin-10; C031818:enterotoxin B, staphylococcal; D007371:Interferon-gamma