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Peyer's patches (or aggregated lymphoid nodules) are organized lymphoid follicles, named after the 17th-century Swiss anatomist Johann Conrad Peyer. [1] They are an important part of gut associated lymphoid tissue usually found in humans in the lowest portion of the small intestine, mainly in the distal jejunum and the ileum, but also could be detected in the duodenum.
The Peyer's patch is an aggregate of lymphoid cells projected to the lumen of the gut which acts as a very important site for the initiation of the immune response. It forms a subepithelial dome where large number of B cell follicles with its germinal centers, T cell areas between them in a smaller number and dendritic cells are found.
Peyer's Patches, groupings of lymphoid follicles in the mucous membrane, monitor the GALT closely to regulate pathogens that traverse through the area. Due to the function of M cells in Peyer's patches, involving the adherence and transport of antigens across a single layer of epithelial cells, dysfunction in these structures could allow an ...
Secondary lymphoid tissue provides the environment for the foreign or altered native molecules (antigens) to interact with the lymphocytes. It is exemplified by the lymph nodes, and the lymphoid follicles in tonsils, Peyer's patches, spleen, adenoids, skin, etc. that are associated with the mucosa-associated lymphoid tissue (MALT).
In the ileum there are occasionally Peyer's patches in the lamina propria. Brunner's glands are found in the duodenum but not in other parts of the small intestine. [1] In the colon, epithelium is simple columnar and without villi. Goblet cells, which secrete mucus, are also present. [1]
Factors promoting the differentiation of M cells have yet to be elucidated, but they are thought to develop in response to signals from immune cells found in developing Peyer's patches. [4] B cells have been implicated in the developmental of M cells, since they are also localized in high numbers in the follicular-associated epithelium (FAE).
MadCAM-1 expression is continuous in the high endothelial venules of Peyer's patches and in the micro-vessels of the intestinal tract. [5] MadCAM-1 inhibitors prevent T cell migration to the gut. Structural analysis of the MadCAM-1 protein shows that it is a 41.5 kDa transmembrane protein with a small cytoplasmic tail and a large extracellular ...
In the small intestine, M cells are associated with Peyer's patches. Cup cells are a distinct cell type that produces vimentin. [13] Tuft cells play a part in the immune response. [13] Throughout the digestive tract, the distribution of the different types of epithelial cells varies according to the function of that region. [5]