M cell

From Wikipedia, the free encyclopedia

M cells (or microfold cells) are cells found in the follicle-associated epithelium of the Peyer's patch that have the unique ability to sample antigen from the lumen of the small intestine and deliver it via transcytosis to antigen presenting cells and lymphocytes located in a unique pocket-like structure on their basolateral side.

Contents 1 Structure 2 Pathology 3 Development 4 References 5 External links

[edit] Structure

M cells differ from normal enterocytes in that they lack microvilli on their apical surface, but instead possess broader microfolds that give the cell its name.

The filamentous brush border glycocalyx, an extracellular polysaccharide layer found throughout the intestine attached to enterocytes, is much thinner or absent on M cells.

[edit] 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. ^[1]

CXCR4 tropic but not CCR5 tropic HIV has been noted to be able to bind to M cells and get transported across the epithelium by them. ^[2]

[edit] 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.^[3]

[edit] References

1. ^ Laurent Ouzilou1, Elise Caliot2, Isabelle Pelletier1, Marie-Christine Prévost3, Eric Pringault2 and Florence Colbère-Garapin1. Journal of General Virology (2002), 83, 2177-2182.
2. ^ Grigorios Fotopoulos*, Alexandre Hararidagger , Pierre MichettiDagger , Didier Trono§, Giuseppe Pantaleodagger , and Jean-Pierre Kraehenbuhl. July 1, 2002, 10.1073/pnas.142586899
3. ^ Kraehenbuhl J, Neutra M. "Epithelial M cells: differentiation and function.". Annu Rev Cell Dev Biol 16: 301–32. doi:10.1146/annurev.cellbio.16.1.301. PMID 11031239.  Link

[edit] External links

• Slide at ucsd.edu

v • d • e Anatomy of torso, digestive system: Gastrointestinal tract Upper GI: to stomach Mouth • Pharynx (nasopharynx, oropharynx, hypopharynx) • Esophagus • Crop Upper GI: stomach rugae – gastric pits – cardia/gland – fundus/gland – pylorus/gland – pyloric antrum – pyloric canal – greater curvature – lesser curvature – angular incisure Lower GI: intestines Small intestine: Duodenum (Suspensory muscle, Major duodenal papilla, Minor duodenal papilla) • Duodenojejunal flexure • Jejunum • Ileum • continuous (intestinal villus, crypts of Lieberkühn, circular folds) Junction: Vermiform appendix • Ileocecal valve Large intestine: Cecum • Colon (ascending colon, hepatic flexure, transverse colon, splenic flexure, descending colon, sigmoid colon) • continuous (taenia coli, haustra, epiploic appendix) Lower GI: termination Rectum: Houston valve • rectal ampulla • pectinate line Anal canal: anal valves • anal sinuses • anal columns • Hilton's white line Anus: Sphincter ani internus muscle • Sphincter ani externus muscle Lower GI: lymph GALT: Peyer's patches (M cells)