title: Tumor necrosis factor alpha-mediated toxic shock in Trypanosoma cruzi-infected interleukin 10-deficient mice.
abstract: Using interleukin-10 (IL-10)-deficient (IL-10(-/-)) mice, previous studies revealed a pathological immune response after infection with Trypanosoma cruzi that is associated with CD4(+) T cells and overproduction of proinflammatory cytokines. In this study we further investigate the pathology and potential mediators for the mortality in infected animals. T. cruzi-infected IL-10(-/-) mice showed reduced parasitemia accompanied by increased systemic release of gamma interferon (IFN-gamma), IL-12, and reactive nitrogen intermediates and overproduction of tumor necrosis factor alpha (TNF-alpha). Despite this early resistance, IL-10(-/-) mice died within the third week of infection, whereas all control mice survived acute infection. The clinical manifestation with weight loss, hypothermia, hypoglycemia, hyperkalemia, and increased liver-derived enzymes in the blood together with hepatic necrosis and intravascular coagulation in moribund mice indicated a toxic shock-like syndrome, possibly mediated by the systemic TNF-alpha overproduction. Indeed, high production of systemic TNF-alpha significantly correlated with mortality, and moribund mice died with critically high TNF-alpha concentrations in the blood. Consequent treatment with anti-TNF-alpha antiserum attenuated pathological changes in T. cruzi-infected IL-10(-/-) mice and significantly prolonged survival; the mice died during the fourth week postinfection, again with a striking correlation between regaining high systemic TNF-alpha concentrations and the time of death. Since elevated serum IL-12 and IFN-gamma concentrations were not affected by the administration of antiserum, these studies suggest that TNF-alpha is the direct mediator of this toxic shock syndrome. In conclusion, induction of endogenous IL-10 during experimentally induced Chagas' disease seems to be crucial for counterregulating an overshooting proinflammatory cytokine response resulting in TNF-alpha-mediated toxic shock.
authors.affiliation: Max-Planck-Institute for Immunobiology, Freiburg, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Hölscher
authors.forename: M
authors.initials: M
authors.lastname: Mohrs
authors.forename: W J
authors.initials: WJ
authors.lastname: Dai
authors.forename: G
authors.initials: G
authors.lastname: Köhler
authors.forename: B
authors.initials: B
authors.lastname: Ryffel
authors.forename: G A
authors.initials: GA
authors.lastname: Schaub
authors.forename: H
authors.initials: H
authors.lastname: Mossmann
authors.forename: F
authors.initials: F
authors.lastname: Brombacher
mesh_terms: D000818:Animals; D014355:Chagas Disease / Q000150:complications* / Q000276:immunology* / Q000473:pathology; D005260:Female; D007249:Inflammation / Q000276:immunology; D007371:Interferon-gamma / Q000096:biosynthesis; D016753:Interleukin-10 / Q000096:biosynthesis / Q000172:deficiency* / Q000235:genetics; D018664:Interleukin-12 / Q000096:biosynthesis; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009500:Neutralization Tests; D018512:Parasitemia / Q000276:immunology; D012772:Shock, Septic / Q000209:etiology* / Q000276:immunology* / Q000503:physiopathology; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors / Q000096:biosynthesis*
chemical_list: D014409:Tumor Necrosis Factor-alpha; D016753:Interleukin-10; D018664:Interleukin-12; D007371:Interferon-gamma