RESUMO
BACKGROUND & AIMS: CD1d is a major histocompatibility complex class I-like molecule that presents glycolipid antigens to a subset of natural killer (NK)1.1(+) T cells. These NK T cells exhibit important immunoregulatory functions in several autoimmune disease models. METHODS: To investigate whether CD1d and NK T cells have a similar role in intestinal inflammation, the effects of the glycolipid, alpha-galactosylceramide (alpha-GalCer), on dextran sodium sulfate (DSS)-induced colitis were examined. Wild-type (WT), CD1d(-/-), and RAG(-/-) mice were examined for their response to either alpha-GalCer or the control analogue, alpha-mannosylceramide (alpha-ManCer). RESULTS: WT mice, but not CD1d(-/-) and RAG(-/-) mice, receiving alpha-GalCer had a significant improvement in DSS-induced colitis based on body weight, bleeding, diarrhea, and survival when compared with those receiving alpha-ManCer. Elimination of NK T cells through antibody-mediated depletion resulted in a reduction of the effect of alpha-GalCer. Furthermore, adoptive transfer of NK T cells preactivated by alpha-GalCer, but not alpha-ManCer, resulted in diminished colitis. Using a fluorescent-labeled analogue of alpha-GalCer, confocal microscopy localized alpha-GalCer to the colonic surface epithelium of WT but not CD1d(-/-) mice, indicating alpha-GalCer binds CD1d in the intestinal epithelium and may be functionally active at this site. CONCLUSIONS: These results show an important functional role for NK T cells, activated by alpha-GalCer in a CD1d-restricted manner, in regulating intestinal inflammation.
Assuntos
Antígenos CD1/farmacologia , Colite/prevenção & controle , Galactosilceramidas/farmacologia , Células Matadoras Naturais/fisiologia , Linfócitos T/fisiologia , Animais , Antígenos CD1/genética , Antígenos CD1d , Colite/induzido quimicamente , Sulfato de Dextrana , Galactosilceramidas/farmacocinética , Genes RAG-1/genética , Mucosa Intestinal/metabolismo , Células Matadoras Naturais/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout/genética , Isoformas de Proteínas/farmacocinética , Isoformas de Proteínas/farmacologia , Linfócitos T/efeitos dos fármacosRESUMO
Helicobacter pylori NCTC 11637 produces a water-insoluble biofilm when grown under defined conditions with a high carbon:nitrogen ratio in continuous culture and in 10% strength Brucella broth supplemented with 3 g l-1 glucose. Biofilm accumulated at the air/liquid interface of the culture. Light microscopy of frozen sections of the biofilm material showed few bacterial cells in the mass of the biofilm. The material stained with periodic acid Schiff's reagent. Fucose, glucose, galactose, and glycero-manno-heptose, N-acetylglucosamine and N-acetylmuramic acid were identified in partially purified and in crude material, using gas chromatography and mass spectrometry. The sugar composition strongly indicates the presence of a polysaccharide as a component of the biofilm material. Antibodies (IgG) to partially purified material were found in both sero-positive and sero-negative individuals. Treatment of the biofilm material with periodic acid reduced or abolished immunoreactivity. Treatment with 5 mol l-1 urea at 100 degrees C and with phenol did not remove antigenic recognition by patient sera. The production of a water-insoluble biofilm by H. pylori may be important in enhancing resistance to host defence factors and antibiotics, and in microenvironmental pH homeostasis facilitating the growth and survival of H. pylori in vivo.
Assuntos
Biofilmes/crescimento & desenvolvimento , Helicobacter pylori/crescimento & desenvolvimento , Aminoácidos/análise , Anticorpos Antibacterianos/sangue , Meios de Cultura/química , Infecções por Helicobacter/imunologia , Infecções por Helicobacter/microbiologia , Helicobacter pylori/imunologia , Humanos , Concentração de Íons de Hidrogênio , Immunoblotting , Imunoglobulina G/sangue , Monossacarídeos/análiseAssuntos
Adjuvantes Imunológicos/farmacologia , Toxina da Cólera/farmacologia , Enterotoxinas/farmacologia , Proteínas de Escherichia coli , Adjuvantes Imunológicos/química , Animais , Toxinas Bacterianas/química , Toxinas Bacterianas/farmacologia , Sequência de Carboidratos , Toxina da Cólera/química , Enterotoxinas/química , Gangliosídeo G(M1)/química , Guanilato Ciclase/química , Humanos , Imunoterapia , Dados de Sequência Molecular , Receptores de Superfície Celular/química , Receptores de Enterotoxina , Receptores Acoplados a Guanilato Ciclase , Receptores de Peptídeos/química , Vacinas/administração & dosagemRESUMO
We have previously shown that the hypersensitivity of KB MDR cells to 2-deoxy-D-glucose is associated with diminished plasma membrane GLUT-1 levels compared with parental, non-MDR cells. Here we report that MDR cells are hypersensitive to the N-linked glycosylation inhibitor tunicamycin, which induces partial inhibition of GLUT-1 glycosylation and diminishes GLUT-1-mediated transport. The effect of tunicamycin, which also enhances the hypersensitivity of MDR cells to 2-deoxy-D-glucose, could not be attributed to alterations in P-glycoprotein activity. The use of agents that act synergistically to diminish the level and activity of GLUT-1 in MDR cells may be of clinical potential.
