- M cell
M cells (or microfold cells) are cells found in the follicle-associated epithelium of the
Peyer's patch that have the unique ability to sampleantigen from the lumen of thesmall intestine and deliver it viatranscytosis toantigen presenting cells andlymphocytes located in a unique pocket-like structure on their basolateral side.tructure
M cells differ from normal
enterocytes in that they lackmicrovilli on their apical surface, but instead possess broader microfolds that give the cell its name. These cells are also far less abundant than enterocytes.The filamentous brush border
glycocalyx , an extracellular polysaccharide layer found throughout the intestine attached to enterocytes, is much thinner or absent on M cells.Pathology
M cells are exploited by several pathogens, including "
Shigella flexneri ", "Salmonella typhimurium ", and "Yersinia pseudotuberculosis ", as a way to penetrate the intestinal epithelium.EPEC containg plasmids with genes for EAF(E coli Adherence Factor)will adhere to M cells.They are also exploited by viruses such as Polio and Reovirus for dissemination. [Laurent Ouzilou1, Elise Caliot2, Isabelle Pelletier1, Marie-Christine Prévost3, Eric Pringault2 and Florence Colbère-Garapin1. Journal of General Virology (2002), 83, 2177-2182.]
CXCR4 tropic but notCCR5 tropic HIV has been noted to be able to bind to M cells and get transported across the epithelium by them. [Grigorios Fotopoulos*, Alexandre Hararidagger , Pierre MichettiDagger , Didier Trono§, Giuseppe Pantaleodagger , and Jean-Pierre Kraehenbuhl. July 1, 2002, 10.1073/pnas.142586899]Development
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 the developing Peyer's patch. [cite journal | author = Kraehenbuhl J, Neutra M | title = Epithelial M cells: differentiation and function. | journal = Annu Rev Cell Dev Biol | volume = 16 | issue = | pages = 301–32 | year = | pmid = 11031239 | doi = 10.1146/annurev.cellbio.16.1.301 [http://arjournals.annualreviews.org/doi/abs/10.1146%2Fannurev.cellbio.16.1.301 Link] ]
References
External links
* [http://meded.ucsd.edu/hist-img-bank/chapter_4/Slide_61_peyers/pages/b.4.61.1.5.htm Slide at ucsd.edu]
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