ABSTRACT
MyD88 is a key adaptor molecule for signalling via Toll-like receptors (TLRs) and the response to gut commensal microbes. To investigate the role of TLRs/MyD88 pathway in the development of the gut-associated lymphoid tissue (GALT), we examined the development of Peyer's patches (PPs) and cryptopatch (CP), and also one of effector compartment, intraepithelial lymphocyte (IEL) in MyD88-/-, TLR2-/- and TLR4-/- mice. In MyD88-/- mice, the organogenesis of PPs was not disturbed. However, PPs in 2-week-old MyD88-/- mice were significantly smaller than those in MyD88+/- mice. Also, in 2-week-old TLR4-/-, but not TLR2-/- mice, PPs did not develop rapidly. The development of PPs in MyD88-/- and TLR4-/- mice was completely recovered in 10 weeks. PP cells from MyD88-/- mice showed significant decrease in proliferation when stimulated with lipopolysaccharide. The development of CP and IEL was also normal in 10-week-old MyD88-/- mice. These results suggest that the TLRs/MyD88 pathway might be involved in the development of PPs only at early postnatal stage, and TLRs/MyD88-independent signalling is critically involved in the development of GALT in adult mice.
Subject(s)
Antigens, Differentiation/physiology , Intestinal Mucosa/immunology , Lymphoid Tissue/growth & development , Peyer's Patches/growth & development , Receptors, Immunologic/physiology , Adaptor Proteins, Signal Transducing , Animals , Cell Division/drug effects , Lipopolysaccharides/pharmacology , Membrane Glycoproteins/physiology , Mice , Mice, Inbred C57BL , Myeloid Differentiation Factor 88 , Receptors, Cell Surface/physiology , Spleen/growth & development , Toll-Like Receptor 2 , Toll-Like Receptor 4 , Toll-Like ReceptorsABSTRACT
Fas/Fas ligand (FasL) interaction has been implicated in the pathogenesis of various diseases. To clarify the involvement of Fas/FasL in the pathogenesis of intestinal inflammation, we investigated the preventive and therapeutic effects of neutralizing anti-FasL monoclonal antibody (MAb) on the development of chronic colitis induced by adaptive transfer of CD4+CD45RBhigh T cells to SCID mice. Administration of anti-FasL MAb from 1 day after T cell transfer (prevention study) resulted in a significant improvement of clinical manifestations such as wasting and diarrhea. However, histological examination showed that mucosal inflammation in the colon, such as infiltration of T cells and macrophages, was not improved by the anti-FasL MAb treatment. In vitro studies showed that anti-FasL MAb did not inhibit IFN-gamma production by anti-CD3/CD28-stimulated lamina propria CD4+ T cells but suppressed TNF-alpha and IL-1beta production by lamina propria mononuclear cells. Therapeutic administration of anti-FasL MAb from 3 wk after T cell transfer also improved ongoing wasting disease but not intestinal inflammation. These results suggest that the Fas/FasL interaction plays a critical role in regulating systemic wasting disease but not local intestinal inflammation.
Subject(s)
Antibodies, Monoclonal/therapeutic use , Colitis/complications , Membrane Glycoproteins/immunology , Wasting Syndrome/therapy , fas Receptor/physiology , Adoptive Transfer , Animals , CD4 Antigens/analysis , CD4 Lymphocyte Count , CD4-Positive T-Lymphocytes/pathology , Chronic Disease , Colitis/immunology , Colitis/pathology , Colitis/therapy , Colon/pathology , Cytokines/biosynthesis , Fas Ligand Protein , Female , Flow Cytometry , Immunohistochemistry , Leukocyte Common Antigens/analysis , Macrophages/pathology , Membrane Glycoproteins/physiology , Mice , Mice, Inbred BALB C , Mice, SCID , T-Lymphocytes/immunology , Wasting Syndrome/etiology , Wasting Syndrome/pathology , fas Receptor/immunologyABSTRACT
Lympho-haemopoietic progenitors residing in murine gut cryptopatches (CPs) have been shown to generate intestinal extrathymic intraepithelial lymphocytes (IELs). However, the role of CPs in the development of intestinal inflammation remains unclear. To investigate the role of CPs in the development of intestinal inflammation, we examined SAMP1/Yit mice, which spontaneously develop a chronic intestinal inflammation localized to the terminal ileum and cecum. Here, we showed the sharp correlation between the disease onset and the decreased number of CPs, resulting in decreased number of both thymus-independent IELs including T-cell receptor gammadelta+ (TCRgammadelta+) and CD8alphaalpha+TCRalphabeta+ cells but not thymus-dependent CD8alphabeta+TCRalphabeta+ and CD4+TCRalphabeta+ cells in SAMP1/Yit mice. These data provide the first suggestion that thymus-independent IELs derived from CP might play protective role against the onset and the development of intestinal inflammation.
Subject(s)
Crohn Disease/metabolism , Intestinal Mucosa/metabolism , Lymphocytes/metabolism , Animals , Chronic Disease , Crohn Disease/immunology , Disease Models, Animal , Ileum/pathology , Immunohistochemistry , Intestinal Mucosa/immunology , Lymphocytes/immunology , MiceABSTRACT
T-cell co-stimulatory molecule, inducible co-stimulator (ICOS)/B7-related protein-1 (B7RP-1) interactions play an essential role of T-cell-dependent B-cell activation in peripheral lymphoid organs such as spleen and lymph nodes. Here, we investigate the role of ICOS/B7RP-1 interactions in the development of Peyer's patches (PPs). In ICOS(-/-) mice, the number of PPs was not decreased, although PPs in ICOS(-/-) mice were significantly reduced in size. Phenotypic analysis showed no obvious differences between ICOS(-/-) and ICOS(+/-) mice in the distribution of T-cells, B-cells, macrophages and dendritic cells. However, PNA(+) cells characteristic of intestinal germinal centers were totally absent in ICOS(-/-) mice. Moreover, production of IgA and IgG, but not IgM was significantly reduced in PPs in ICOS(-/-) mice. These data suggest that ICOS/B7RP-1 interactions may not affect the organogenesis, but involve in the functional development of PPs.
Subject(s)
Antigens, Differentiation, T-Lymphocyte/immunology , Antigens, Differentiation, T-Lymphocyte/physiology , B7-1 Antigen/physiology , Peyer's Patches/growth & development , Peyer's Patches/immunology , Animals , Antigens, Differentiation, T-Lymphocyte/genetics , Antigens, Differentiation, T-Lymphocyte/metabolism , B-Lymphocytes/immunology , B7-1 Antigen/genetics , Cell Count , Cytokines/biosynthesis , Gene Targeting , Germinal Center/physiology , Immunoglobulins/biosynthesis , Inducible T-Cell Co-Stimulator Ligand , Inducible T-Cell Co-Stimulator Protein , Mice , Mice, Knockout , Peyer's Patches/cytology , T-Lymphocytes/immunologyABSTRACT
Interaction of OX40 (CD134) on T cells with its ligand (OX40L) on antigen-presenting cells has been implicated in pathogenic T cell activation. This study was performed to explore the involvement of OX40/OX40L in the development of T cell-mediated chronic colitis. We evaluated both the preventive and therapeutic effects of neutralizing anti-OX40L MAb on the development of chronic colitis in SCID mice induced by adoptive transfer of CD4(+)CD45RB(high) T cells as an animal model of Crohn's disease. We also assessed the combination of anti-OX40L and anti-TNF-alpha MAbs to improve the therapeutic effect. Administration of anti-OX40L MAb markedly ameliorated the clinical and histopathological disease in preventive and therapeutic protocols. In vivo treatment with anti-OX40L MAb decreased CD4(+) T cell infiltration in the colon and suppressed IFN-gamma, IL-2, and TNF-alpha production by lamina propria CD4(+) T cells. The combination with anti-TNF-alpha MAb further improved the therapeutic effect by abolishing IFN-gamma, IL-2, and TNF-alpha production by lamina propria CD4(+) T cells. Our present results suggested a pivotal role of OX40/OX40L in the pathogenesis of T cell-mediated chronic colitis. The OX40L blockade, especially in combination with the TNF-alpha blockade, may be a promising strategy for therapeutic intervention of Crohn's disease.
Subject(s)
Antibodies, Monoclonal/pharmacology , Antigens, Differentiation/pharmacology , Colitis/therapy , Tumor Necrosis Factor-alpha/immunology , Animals , CD4-Positive T-Lymphocytes/immunology , Chronic Disease , Colitis/immunology , Colitis/prevention & control , Disease Models, Animal , Female , Membrane Glycoproteins/immunology , Mice , Mice, Inbred BALB C , Mice, SCID , OX40 Ligand , Tumor Necrosis FactorsABSTRACT
A mer operon of mercury-resistant Pseudoalteromonas haloplanktis strain M1, isolated from sea water of Minamata Bay, was cloned and analyzed. The mer genes were located in the chromosome and organized as merR-merT-merP-merC-merA-merD, the same order as that in Tn21. However, the orientation of the merR gene is the same as that of other mer genes (opposite direction to Tn21), and merR was cotranscribed with other mer genes, a pattern that has not been previously seen with mer determinants from other Gram-negative bacteria. Furthermore, the amino acid similarities of the corresponding mer gene products between those from strain M1 and Tn21 were unusually low.
Subject(s)
Drug Resistance, Bacterial/genetics , Gammaproteobacteria/drug effects , Mercury/pharmacology , Operon , Oxidoreductases/genetics , Amino Acid Sequence , Cloning, Molecular , Gammaproteobacteria/genetics , Gammaproteobacteria/isolation & purification , Molecular Sequence Data , Oxidoreductases/chemistry , Oxidoreductases/metabolism , Seawater/microbiology , Sequence Analysis, DNAABSTRACT
BACKGROUND & AIMS: Crohn's disease (CD) is associated with an increased number of infiltrating macrophages, which release a variety of proinflammatory cytokines. Interleukin (IL)-18 has been implicated in the modulation of mucosal CD4(+) T cells towards Th1 responses, which are implicated in the pathogenesis of CD. Here we assess the role of macrophages and of IL-18 in the murine model of intestinal inflammation that mimics the immunologic characteristics of human CD. METHODS: Colitis was induced in C57BL/6 mice immunized with 2,4,6-trinitrobenzene sulfonic acid (TNBS) followed by rectal administration of TNBS in ethanol. Mice were treated with either an antibody directed against macrophages conjugated to the ribosome-inactivating protein saporin (anti-Mac-1-saporin) or with a neutralizing antibody against IL-18. In addition, we assessed whether an identical TNBS immunization/challenge protocol could induce colitis in IL-18(-/-) mice. RESULTS: The colonic mucosa of TNBS-treated mice was marked by infiltration of Mac-1-positive macrophages and up-regulation of IL-18. The administration of the anti-Mac-1-saporin antibody or the neutralizing anti-IL-18 antibody resulted in a dramatic attenuation of mucosal inflammation in this model. In addition, TNBS was unable to induce significant colitis in the IL-18(-/-) mice. CONCLUSIONS: Our data underscore the pivotal role of macrophages, and the macrophage-derived IL-18, in the establishment of TNBS-induced colitis in mice. Our results highlight the potential use of therapy directed against IL-18 in the treatment of patients with CD.
