Characterization of antigen and bacterial transport in the follicle-associated epithelium of human ileum
| Autor: | Sa’ad Y. Salim, Ann-Charlott Ericson, Johan D. Söderholm, Anders Kald, Elisabet Gullberg, Åsa V. Keita, Per Artursson, Conny Wallon |
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| Rok vydání: | 2006 |
| Předmět: |
Adult
Male Biology Pathology and Forensic Medicine law.invention Microbiology Peyer's Patches Intestinal mucosa Microscopy Electron Transmission Confocal microscopy law Ileum medicine Escherichia coli Humans Lymphocytes Transcellular Antigens Intestinal Mucosa Molecular Biology Barrier function Edetic Acid Horseradish Peroxidase Aged Aged 80 and over Biological Transport Cell Biology Middle Aged Molecular biology Epithelium In vitro Small intestine Actins Chromium Radioisotopes Coculture Techniques medicine.anatomical_structure Paracellular transport Female |
| Zdroj: | Laboratory investigation; a journal of technical methods and pathology. 86(5) |
| ISSN: | 0023-6837 |
| Popis: | The follicle-associated epithelium (FAE), covering Peyer's patches, provides a route of entry for antigens and microorganisms. Animal studies showed enhanced antigen and bacterial uptake in FAE, but no study on barrier function of human FAE has been reported. Our aim was to characterize the normal barrier properties of human FAE. Specimens of normal ileum were taken from 30 patients with noninflammatory colonic disease. Villus epithelium (VE) and FAE were identified and mounted in Ussing chambers. Permeability to 51Cr-EDTA, transmucosal flux of the protein antigen, horseradish peroxidase (HRP), and transport of fluorescent Escherichia coli (chemically killed K-12 and live HB101) were measured. Uptake mechanisms were studied by confocal- and transmission electron microscopy, and by using pharmacological inhibitors in an in vitro coculture model of FAE and in human ileal FAE. HRP flux was substantially higher in FAE than in VE, and was reduced by an amiloride analog. Electron microscopy showed HRP-containing endosomes. Transport of E. coli K-12 and HB101 was also augmented in FAE and was confirmed by confocal microscopy. In vitro coculture experiments and electron microscopy revealed actin-dependent, mainly transcellular, uptake of E. coli K-12 into FAE. 51Cr-EDTA permeability was equal in FAE and VE. Augmented HRP flux and bacterial uptake but similar paracellular permeability, suggest functional variations of transcellular transport in the FAE. We show for the first time that FAE of human ileum is functionally distinct from regular VE, rendering the FAE more prone to bacterial-epithelial cell interactions and delivery of antigens to the mucosal immune system. |
| Databáze: | OpenAIRE |
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