title: Helicobacter hepaticus-induced colitis in interleukin-10-deficient mice: cytokine requirements for the induction and maintenance of intestinal inflammation.
abstract: We have previously shown that specific-pathogen-free interleukin-10 (IL-10)-deficient (IL-10 KO) mice reconstituted with Helicobacter hepaticus develop severe colitis associated with a Th1-type cytokine response. In the present study, we formally demonstrate that IL-12 is crucial for disease induction, because mice deficient for both IL-10 and IL-12 p40 show no intestinal pathology following H. hepaticus infection. By using monoclonal antibodies (MAbs) to IL-12, gamma interferon (IFN-gamma), and tumor necrosis factor alpha (TNF-alpha), we have further analyzed the role of these cytokines in the maintenance of the Th1 response and inflammation in IL-10 KO mice with established H. hepaticus-induced colitis. Treatment of infected colitic IL-10 KO mice with anti-IL-12 p40 resulted in markedly reduced intestinal inflammation, colonic IFN-gamma, TNF-alpha, and inducible nitric oxide synthase (iNOS) mRNA levels, and H. hepaticus-specific IFN-gamma secretion by mesenteric lymph node (MLN) cells compared to the findings in control MAb-treated mice. Moreover, the diminished pathology was associated with decreased numbers of colonic CD3(+) T cells and significantly reduced frequencies of Helicobacter-reactive CD4(+) Th1 cells in MLN. In contrast, anti-IFN-gamma and/or anti-TNF-alpha had no effect on intestinal inflammation in IL-10 KO mice with established colitis. Using IL-10/IFN-gamma double-deficient mice, we further show that IFN-gamma is not required for the development of colitis following H. hepaticus infection. MLN cells from infected IL-10/IFN-gamma KO animals secreted elevated amounts of IL-12 and TNF-alpha following bacterial antigen stimulation, indicating alternative pathways of disease induction. Taken together, our results demonstrate a crucial role for IL-12 in both inducing and sustaining intestinal inflammation through recruitment and maintenance of a pool of pathogenic Th1 cells.
authors.affiliation: Immunobiology Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland 20892-0425, USA. mkullberg@niaid.nih.gov
authors.forename: M C
authors.initials: MC
authors.lastname: Kullberg
authors.forename: A G
authors.initials: AG
authors.lastname: Rothfuchs
authors.forename: D
authors.initials: D
authors.lastname: Jankovic
authors.forename: P
authors.initials: P
authors.lastname: Caspar
authors.forename: T A
authors.initials: TA
authors.lastname: Wynn
authors.forename: P L
authors.initials: PL
authors.lastname: Gorelick
authors.forename: A W
authors.initials: AW
authors.lastname: Cheever
authors.forename: A
authors.initials: A
authors.lastname: Sher
mesh_terms: D000818:Animals; D017252:CD3 Complex / Q000276:immunology; D003092:Colitis / Q000276:immunology* / Q000473:pathology; D016207:Cytokines / Q000235:genetics / Q000276:immunology*; D004198:Disease Susceptibility / Q000276:immunology; D005260:Female; D016998:Helicobacter; D016481:Helicobacter Infections / Q000276:immunology* / Q000473:pathology; D007371:Interferon-gamma / Q000235:genetics / Q000276:immunology; D016753:Interleukin-10 / Q000276:immunology*; D018664:Interleukin-12 / Q000276:immunology; D015847:Interleukin-4 / Q000276:immunology; D007422:Intestines / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D019001:Nitric Oxide Synthase / Q000235:genetics; D052247:Nitric Oxide Synthase Type II; D013601:T-Lymphocytes / Q000276:immunology; D018417:Th1 Cells / Q000276:immunology; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000276:immunology
chemical_list: D017252:CD3 Complex; D016207:Cytokines; D014409:Tumor Necrosis Factor-alpha; D016753:Interleukin-10; D018664:Interleukin-12; D015847:Interleukin-4; D007371:Interferon-gamma; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse