M cell

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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 do not have microvilli on their apical surface, but broader microfolds that give the cell its name.

The filamentous brush border glycocalyx, an extracellular polysaccharide layer found thoughout 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.

[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.^[1]

[edit] References

1. ^ Kraehenbuhl J, Neutra M. "Epithelial M cells: differentiation and function.". Annu Rev Cell Dev Biol 16: 301-32. PMID 11031239. Link

[edit] External links

• Slide at ucsd.edu

Gastrointestinal tract v • d • e

Upper gastrointestinal tract Mouth | Pharynx (nasopharynx, oropharynx, hypopharynx) | Esophagus | Crop | Stomach (rugae, gastric pits, cardia, pylorus) Lower gastrointestinal tract Small intestine (duodenum, jejunum, ileum) | Vermiform appendix Large intestine: Cecum | Colon (ascending colon, transverse colon, descending colon, sigmoid colon) | Rectum (Houston valve, rectal ampulla, pectinate line) | Anal canal (anal valves, anal sinuses, anal columns) Anus: Sphincter ani internus muscle | Sphincter ani externus muscle Enteric nervous system: Meissner's plexus | Auerbach's plexus Enteroendocrine cells: G cells | Enterochromaffin cells | Enterochromaffin-like cell GALT: Peyer's patches | M cells parietal cells | chief cells | goblet cells | Brunner's glands | Paneth cells | enterocytes intestinal villus | crypts of Lieberkühn | circular folds | taenia coli | haustra | epiploic appendix