The accessory cell function of murine Peyer's patches

The cellular composition and certain functional characteristics of murine Peyer's patches (PP) were examined and compared with other lymphoid tissues. The composition of PP resembled most closely that of the spleen with the exception of a significant decrease in the number of adherent and phagocytic cells. Very few cells with dendritic morphology could be identified in Peyer's patches. Whole PP (and the nonadherent population) were capable of presenting antigen ovalbumin, human gammaglobulin, and purified protein derivative in a T proliferative assay to sensitized lymph node cells and to an antigen-specific T-cell clone. The antigen-presenting cell in both the spleen and PP was concentrated in the low-density population which floated on 1.080 bovine plasma albumin. However, equal numbers of whole and PP floaters were deficient in their capacity to present antigen compared with similar populations from spleen. Moreover, in PP the antigen-presenting cell appeared in the nonadherent rather than the adherent population as found with other lymphoid tissues. Similar results were obtained with (B6A)F1, CBA, A.TFR-1 and B10.S (12R) mice, suggesting that the inability of adherent cells from PP to present antigen effectively was not genetically determined. Whole and nonadherent PP contained cells capable of stimulating an allogeneic MLR, although again they were generally inferior to those of the spleen when comparable numbers of cells were employed. The adherent population of PP did not elicit an MLR. However, whole PP contained accessory cells needed for mitogen-induced proliferation since passage over nylon-wool columns resulted in a nonadherent fraction which did not respond to concanavalin A or phytohemagglutinin and the addition of adherent peritoneal exudate cells restored the lectin response. The differences noted in the accessory cell function in PP and other lymphoid tissues suggest the possibility that quantitative or qualitative differences in the function of these cells may explain some of the previously observed characteristics of PP, such as the inability to detect a primary antibody response in this tissue. The possibility that the development of gut-associated suppressor cells and their migration to peripheral tissues may be involved in the systemic tolerance that follows oral immunization and that these may be related to numerical and/or functional differences in macrophages or accessory cells is discussed.     

Formation of Peyer's patches

Formation of Peyer's patches requires complex interactions between the gut epithelium, the mesenchyme, and bone-marrow-derived hematopoietic progenitors. The first Peyer's patches anlage appear around embryonic day 15.5, when the endoderm has undergone transition to a simple epithelium, the lymphatic vessels have reached the intestinal mucosa, and mesenchymal cells have started to form clusters. Recent data using knockout mice provide insight into the molecular nature of the signals that mediate Peyer's patch ontogeny. These include members of the tumor-necrosis factor family and homeostatic chemokines.     

Vimentin-positive epithelial cells in aggregated lymphoid nodules (Peyer's patches) in rabbits

Peculiarities of cytoskeleton in membranous cells and disposition of the latter in the cupola epithelium in aggregated lymphoid nodules++ (ALN) have been studied in the ileum of 5 rabbits. The material has been fixed in liquid nitrogen and in the mixture of paraformaldehyde and glutar aldehyde. Methods of immunomorphology, high resolving light and transmissive electron microscopy have been used. Monoclonal antibodies to vimentin are selectively bind with a specific population of the ALN cupola epithelial cells. These cells are regularly arranged in the epithelium of the cupola lateral part and they are absent in the epithelium of the intestinal crypts, villi and apex of the cupolas. In the lateral epithelium of the cupolas surface, nearer to their base vimentin-positive++ epitheliocytes make contacts with single interepitheliocytic lymphocytes, and nearer to the apex they surround compact groups of the interepitheliocytic lymphocytes. The vimentin-positive++ epitheliocytic cells are identified as M-cells.     

Lectin binding reveals divergent carbohydrate expression in human and mouse Peyer's patches

The nature of cell-associated carbohydrates in the human intestine that may mediate transepithelial transport of bacterial and dietary lectins and their processing by the lymphoid cells of Peyer's patches is not known. Because the cell surface carbohydrate receptors for lectins may vary in different species, the glycoconjugates of human and mouse follicle-associated epithelium and gut-associated lymphoid tissue were compared. A panel of 27, mainly recently isolated, lectins were used to identify glycoconjugate expression in M-cells, enterocytes, goblet cells, lymphocytes and macrophages in mouse and human intestine. Mouse M-cells were exclusively labelled by fucose-specific lectins but in human follicle-associated epithelium no distinct M-cell staining pattern was observed. In the human Peyer's patches,Bryonia dioica lectin bound selectively to paracortical T-lymphocytes andChelidonium majus lectin to germinal centre B-cells. Certain mannose-specific lectins (Galanthus nivalis, Hippeastrum hybrid) stained the tingible body macrophages in the germinal centre of human Peyer's patches but labelled the macrophages in the paracortical T-cell region of the mouse. The results indicate distinct differences in glycosylation between mouse and human Peyer's patches and their associated lymphoid cells. When considering cell surface glycoconjugates as target molecules for the gut immune system, care has to be taken to choose the appropriate lectin for each species.     

Correlation of extracellular matrix components with the cytoarchitecture of mouse Peyer's patches

Summary The distribution patterns of extracellular matrix elements were determined to ascertain whether they play a role in the localization of lymphocytes in discrete T-cell, B-cell and dome antigen-processing domains within Peyer's patches. Antibodies against collagen types I, III and IV, laminin and fibronectin were applied to cryosections of mouse Peyer's patches and localized by direct or indirect immunoperoxidase methods. T-cell domains were identified with a monoclonal antibody against Thy-1.2. Labeled reticular fibers in distinctive patterns were more numerous in parafollicular and dome areas than within follicles. Germinal centers contained few such fibers. In parafollicular areas, fibers were oriented predominantly toward follicle domes; their distribution corresponded to T-cell zones and lymphocyte traffic areas, with their orientation being parallel to the migration pathways of lymphocytes from high endothelial venules to the antigen-processing domes. Subepithelial and subendothelial basal laminae were immunopositive for type-IV collagen, laminin and fibronectin. The dome subepithelial basal lamina had pore-like discontinuities through which lymphocytes migrated to and from the epithelium. The correspondence of the distribution patterns of extracellular matrix to specific functional domains of Peyer's patches suggests that this matrix provides a structural framework for lymphocyte migration and localization.     

Particles and macrophages in murine Peyer's patches

Mice were given 1% suspensions of 5 insoluble particles (chrysotile asbestos, quartz, carmine, carbon, and iron oxide) in drinking water for 3 months. The particles were subsequently sought in intestinal Peyer's patches by light microscopy. Carbon and iron oxide particles were visible in Peyer's patch macrophages, particularly in the subepithelial region, but the other particles could not be detected. The findings suggest that particle surface properties as well as particle size govern accumulation in Peyer's patches. The cytochemistry of subepithelial, mid-dome, tingible-body, and serosal macrophages of control mice indicated diversity of macrophages within the patch. Macrophages of asbestos-fed mice contained more lysosomes than macrophages of controls. Macrophage abundance in the dome apex was not significantly altered by asbestos ingestion. The other particles did not produce detectable alterations in macrophage morphology.     

Immunohistochemical examination of Peyer's patches in autoimmune mice

The distribution of T-cells and B-cells in Peyer's patches was examined in three autoimmune model mice, MRL/Mp-lpr/lpr, BXSB, NZBWF1/J mice and normal BALB/c mice, between one and ten months old. A multiple layering technique was used for immunohistochemical detection of lymphocyte surface antigens of T-cells (Thy1.2, Lyt1, Lyt2) and B-cells (surface IgM) and peanut agglutinin receptor for germinal center cells. The T-cell population of female MRL/Mp-lpr/lpr mice increased markedly with age, and the B-cell population of the male BXSB mouse tended to increase. However, little change was observed with age in the NZBWF1/J mice. The immunohistochemical properties of the Peyer's patches in the three autoimmune model mice were different.     

Immunohistochemical examination of Peyer's patches in autoimmune mice

Summary The distribution of T-cells and B-cells in Peyer's patches was examined in three autoimmune model mice, MRL/Mp-lpr/lpr, BXSB, NZBWF1/J mice and normal BALB/c mice, between one and ten months old. A multiple layering technique was used for immunohistochemical detection of lymphocyte surface antigens of T-cells (Thy1.2, Lyt1, Lyt2) and B-cells (surface IgM) and peanut agglutinin receptor for germinal center cells. The T-cell population of female MRL/Mp-lpr/lpr mice increased markedly with age, and the B-cell population of the male BXSB mouse tended to increase. However, little change was observed with age in the NZBWF1/J mice. The immunohistochemical properties of the Peyer's patches in the three autoimmune model mice were different.     

cDNA representational difference analysis of ileal Peyer's patches in lambs after oral inoculation with scrapie

cDNA representational difference analysis (RDA) was used to study gene expression profiles in the ileal Peyer's patch of a lamb 1 week after oral inoculation with the scrapie agent. Twenty-five differentially expressed cDNA fragments were identified and cloned. Sequence analysis indicated seven novel gene sequences. Other clones shared sequence homology with genes encoding ribosomal and mitochondrial proteins, the translation initiation factor EIF4GII and the bovine pancreatic thread protein. Reverse Northern was used to confirm the differential expression in another four lambs inoculated with scrapie and the tissue distribution of the novel genes was examined using Northern blot analysis.     

Automated histochemical analysis of cell populations in the intact follicle-associated epithelium of the mouse Peyer's patch

Summary A new technique of quantitative histochemistry has been developed to study the cellular composition of the follicle-associated epithelium of the mouse Peyer's patch. This technique involves applying naphthol AS-BI phosphate to the surface of intact tissue where it is hydrolysed by alkaline phosphatase present in the luminal membrane of the epithelial cells. Naphthol AS-BI produced by this reaction is then coupled to Fast Red TR diazonium salt at the site of hydrolysis. M cells present in the epithelium contain little alkaline phosphatase activity and, therefore, remain white. Treatment with Alcian Blue is finally used to label goblet cells. Subsequent quantitative analysis of alkaline phosphatase-rich cells is carried out by scanning microdensitometry. Using this technique it is possible to detect two populations of alkaline phosphatase-containing cells in mice reared in a normal animal house environment.These results are discussed in relation to possible interactions taking place between enteric antigens and the gut-associated lymphoid tissue which could reduce the ability of follicle-associated enterocytes to express alkaline phosphatase.     

Selective emigration of suppressor T cells from Peyer's patches

The emigration of Peyer's patch lymphocytes to mesenteric lymph nodes was studied by injecting fluorescein isothiocyanate (FITC) directly into Peyer's patches. Using double immunofluorescence it was demonstrated that at 2 and 4 hr after FITC injection 70% of the labeled cells that migrated to mesenteric lymph nodes were T lymphocytes, although rat Peyer's patches contain only 15-20% T lymphocytes. At later time points after FITC injection this percentage of T cells derived from Peyer's patches gradually declined, most likely caused by selective interaction and/or retention inside the mesenteric lymph node. Determination of helper and suppressor T-cell subsets within this emigrating population showed an increased number of T suppressor cells migrating into mesenteric lymph nodes. The putative role of suppressor T cells in inducing systemic tolerance after oral antigen administration was discussed.