ABSTRACT
BACKGROUND: The afferent limb of the intestinal immune system is represented by the gut-associated lymphoid tissue, in which antigenic material, including complete bacteria, is taken up from the lumen by specialized epithelial cells (M cells). Because the adherence of micro-organisms to epithelial can be mediated by lectin-sugar bindings, the glycoconjugates of the surfaces of M cells and enterocytes were compared. METHODS: A set of 28 lectins and corresponding sugars was used for light and electron microscopy of fixed and unfixed sections. M cells were identified by anti-vimentin antibodies. RESULTS: M cells of the cecal lymphoid patches selectively bound lectins specific for fucose or N-acetylgalactosamine. The labeled glycoconjugates were located in the apical membrane and in the membrane of vesicles in the apical cytoplasm. Enterocytes were selectively labeled by galactose-specific lectins. In contrast, the lectin-reactivity of M cells and enterocytes did not differ in the jejunal Peyer's patches. CONCLUSIONS: The results suggest that there may be selectivity mediated by glycoconjugates in the uptake of antigenic material by cecal M cells but not by jejunal M cells.
Subject(s)
Cecum/cytology , Cecum/immunology , Lectins/metabolism , Lymphoid Tissue/cytology , Animals , Antigens/metabolism , Appendix/metabolism , Appendix/ultrastructure , Bacterial Adhesion , Cecum/metabolism , Epithelium/metabolism , Epithelium/ultrastructure , Female , Glycoconjugates/physiology , In Vitro Techniques , Lymphoid Tissue/metabolism , Male , Microscopy, Electron , Peyer's Patches/metabolism , Peyer's Patches/ultrastructure , RabbitsABSTRACT
The lymphoepithelium covering the bronchus-associated lymphoid tissue (BALT) of the rabbit lung was studied with monoclonal antibodies against vimentin, using the indirect immunoperoxidase technique. In the lymphoepithelium single cells which had a membranous apical cytoplasm and engulfed intraepithelial lymphocytes were vimentin-immunoreactive. All other epithelial cells of the lymphoepithelium and of the surrounding airway epithelium did not bind vimentin antibodies. The results support the hypothesis that the membranous epithelial cells in the lymphoepithelium of rabbit BALT are analogous with intestinal M-cells, which in rabbit Peyer's patches and appendix are selectively labelled by vimentin antibodies.
Subject(s)
Bronchi/metabolism , Peyer's Patches/metabolism , Vimentin/analysis , Animals , Epithelium/metabolism , Female , Immunohistochemistry , Lymphocytes/metabolism , Male , Rabbits , Trachea/metabolismABSTRACT
The occurrence of cytokeratins, vimentin, and desmin in the dome epithelia and adjacent non-dome epithelia in four locations of gut-associated lymphoid tissues (GALT) of adult and newborn rabbits (Peyer's patches, sacculus rotundus, caecal lymphoid patches and appendix) was studied with monoclonal antibodies, using the indirect immunoperoxidase technique. In all locations investigated in adult animals, antibodies specific for vimentin labelled (1) M-cells, which engulf intra-epithelial lymphocytes, (2) columnar epithelial cells at the base of the domes lacking an apparent contact with lymphocytes ("immature" M-cells), and (3) flat cells, which lie in the lamina propria under the dome epithelium, and which line the basal lamina with thin cytoplasmic processes. In newborn rabbits, columnar epithelial cells resembling the immature M-cells of adults were selectively stained with vimentin antibodies. In M-cells, the strongest immunoreactivity was present in the perinuclear region and close to the pocket membrane, whereas the most apical and most basal parts of the cytoplasm showed no vimentin-immunoreactivity. Enterocytes in the dome epithelium and in the non-dome epithelium were vimentin-negative. M-cells and enterocytes bound antibodies against cytokeratin peptides 18 and 19 in adult and newborn animals. Compared with enterocytes, M-cells showed less intense staining for cytokeratins. Dome epithelia and no-dome epithelia did not contain desmin-immunoreactive cells. The results suggest that vimentin is a sensitive marker for M-cells in rabbit GALT.
Subject(s)
Intestinal Mucosa/metabolism , Keratins/metabolism , Lymphoid Tissue/metabolism , Vimentin/metabolism , Animals , Animals, Newborn , Biomarkers , Cell Differentiation , Desmin/metabolism , Female , Immunohistochemistry , Intestines/cytology , Lymphocytes/cytology , Lymphocytes/metabolism , Lymphoid Tissue/cytology , Male , RabbitsABSTRACT
Conventional and Computerized Tomography are radiological techniques with the objective to reproduce tomographique images, both with different features with regard to detail recognition. Both techniques can be considered as methods complementing one another and not as competitive ones following the present stage of development and experiences gained in this field. Conventional Tomography with its proper range of application is regarded as a fully developed technique, whereas Computerized Tomography will possibly allow further development and improvements with regard to technology and performance. The limits, however, in the relation price/performance regarding tomopgraphic equipments and the relation dosage/image quality regarding the method can already be recognized. If we compare both techniques, we may say, however, with certain reservations, that Conventional Tomography stands out for a superior spatial resolution whereas a better distinction between small density differences in tissues one of the most distinguished features is Computerized Tomography is known for.
