title: Critical role for tumor necrosis factor alpha in controlling the number of lumenal pathogenic bacteria and immunopathology in infectious colitis.
abstract: Infection of mice with the intestinal bacterial pathogen Citrobacter rodentium results in colonic mucosal hyperplasia and a local Th1 inflammatory response similar to that seen in mouse models of inflammatory bowel disease. In these latter models, and in patients with Crohn's disease, neutralization of tumor necrosis factor alpha (TNF-alpha) is of therapeutic benefit. Since there is no information on the role of TNF-alpha in either immunity to noninvasive bacterial pathogens or on the role of TNF-alpha in the immunopathology of infectious colitis, we investigated C. rodentium infection in TNFRp55(-/-) mice. In TNFRp55(-/-) mice, there were higher colonic bacterial burdens, but the organisms were cleared at the same rate as C57BL/6 mice, showing that TNF-alpha is not needed for protective antibacterial immunity. The most striking feature of infection in TNFRp55(-/-) mice, however, was the markedly enhanced pathology, with increased mucosal weight and thickness, increased T-cell infiltrate, and a markedly greater mucosal Th1 response. Interleukin-12 p40 transcripts were markedly elevated in C. rodentium-infected TNFRp55(-/-) mice, and this was associated with enhanced mucosal STAT4 phosphorylation. TNF-alpha is not obligatory for protective immunity to C. rodentium in mice; however, it appears to play some role in downregulating mucosal pathology and Th1 immune responses.
authors.affiliation: School of Medicine, University of Southampton, Southampton General Hospital, Southampton SO16 6YD, United Kingdom.
authors.forename: N S
authors.initials: NS
authors.lastname: Gonçalves
authors.forename: M
authors.initials: M
authors.lastname: Ghaem-Maghami
authors.forename: G
authors.initials: G
authors.lastname: Monteleone
authors.forename: G
authors.initials: G
authors.lastname: Frankel
authors.forename: G
authors.initials: G
authors.lastname: Dougan
authors.forename: D J
authors.initials: DJ
authors.lastname: Lewis
authors.forename: C P
authors.initials: CP
authors.lastname: Simmons
authors.forename: T T
authors.initials: TT
authors.lastname: MacDonald
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000235:genetics / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D016971:Citrobacter freundii / Q000254:growth & development / Q000276:immunology*; D003106:Colon / Q000382:microbiology / Q000473:pathology; D003109:Colonic Diseases, Functional / Q000276:immunology* / Q000473:pathology; D004268:DNA-Binding Proteins / Q000378:metabolism; D004756:Enterobacteriaceae Infections / Q000276:immunology* / Q000473:pathology; D005260:Female; D015870:Gene Expression; D006965:Hyperplasia / Q000276:immunology / Q000473:pathology; D018664:Interleukin-12 / Q000235:genetics; D015847:Interleukin-4 / Q000235:genetics; D007413:Intestinal Mucosa / Q000276:immunology / Q000473:pathology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D018124:Receptors, Tumor Necrosis Factor / Q000235:genetics / Q000276:immunology*; D047888:Receptors, Tumor Necrosis Factor, Type I; D050797:STAT4 Transcription Factor; D015534:Trans-Activators / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology*
chemical_list: D015703:Antigens, CD; D004268:DNA-Binding Proteins; D018124:Receptors, Tumor Necrosis Factor; D047888:Receptors, Tumor Necrosis Factor, Type I; D050797:STAT4 Transcription Factor; C494091:Stat4 protein, mouse; D015534:Trans-Activators; D014409:Tumor Necrosis Factor-alpha; D018664:Interleukin-12; D015847:Interleukin-4