title: In vitro activated CD4+ T cells from interferon-gamma (IFN-gamma)-deficient mice induce intestinal inflammation in immunodeficient hosts.
abstract: To investigate the role of IFN-gamma in the immunopathogenesis of inflammatory bowel disease (IBD), severe combined immunodeficient (SCID) mice were transplanted with in vitro activated CD4+ T cells from either wild-type (WT) or IFN-gamma-deficient (IFN-gammaKO) BALB/c mice. In vitro, the two types of T cells displayed comparable proliferation rates and production of tumour necrosis factor-alpha (TNF-alpha), IL-2, IL-4 and IL-10 after concanavalin A (Con A) stimulation. When transplanted into SCID mice, WT CD4+ blasts induced a lethal IBD, whereas IFN-gammaKO blasts induced a less severe intestinal inflammation with moderate weight loss. Intracellular cytokine staining of lamina propria lymphocytes (LPL) revealed comparable fractions of CD4+ T cells positive for TNF-alpha, IL-2 and IL-10 in the two groups of transplanted SCID mice, whereas a two-to-three-fold increase in the fraction of IL-4-positive cells was found in IFN-gammaKO-transplanted SCID mice. Flow cytometric analyses showed strong up-regulation of MHC class II expression of colonic epithelial cells of WT-CD4+ T cell-transplanted compared with IFN-gammaKO-transplanted SCID mice. A significantly higher fraction of CD4+ LPL were found to enter the cell cycle, i.e. to incorporate bromo-deoxy-uridine, and to undergo apoptosis in vivo in WT-transplanted compared with IFN-gammaKO-transplanted SCID mice. These data point towards an important role for IFN-gamma in the development of IBD in SCID mice. The inflammation might be initiated and subsequently enhanced by the ability of IFN-gamma to induce de novo MHC class II expression in the colonic epithelium, a change which could lead to increased antigen processing and production of local proinflammatory cytokines, CD4+ T cell turnover and thereby to exaggeration of disease.
authors.affiliation: Laboratory of Experimental Immunology, Department of Medical Anatomy, The Panum Institute, University of Copenhagen, Copenhagen, Denmark. bregenholt@necker.fr
authors.forename: S
authors.initials: S
authors.lastname: Bregenholt
authors.forename: J
authors.initials: J
authors.lastname: Brimnes
authors.forename: M H
authors.initials: MH
authors.lastname: Nissen
authors.forename: M H
authors.initials: MH
authors.lastname: Claesson
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000235:genetics / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000737:chemistry / Q000276:immunology* / Q000637:transplantation; D002455:Cell Division / Q000235:genetics / Q000276:immunology; D002478:Cells, Cultured; D016207:Cytokines / Q000032:analysis; D000949:Histocompatibility Antigens Class II / Q000096:biosynthesis; D018928:Immunity, Mucosal; D016867:Immunocompromised Host / Q000235:genetics; D015212:Inflammatory Bowel Diseases / Q000235:genetics / Q000276:immunology* / Q000473:pathology; D007371:Interferon-gamma / Q000172:deficiency* / Q000235:genetics; D007413:Intestinal Mucosa / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D008213:Lymphocyte Activation / Q000235:genetics*; D051379:Mice; D008807:Mice, Inbred BALB C; D018345:Mice, Knockout; D016513:Mice, SCID
chemical_list: D016207:Cytokines; D000949:Histocompatibility Antigens Class II; D007371:Interferon-gamma