Microfold cell (M cell)

Microfold cells, commonly known as M cells, are specialized epithelial cells located within the follicle-associated epithelium (FAE) of Peyer's patches and other mucosa-associated lymphoid tissues (MALT) (Mabbott et al., 2013, Nature Reviews Microbiology). Unlike typical enterocytes, M cells possess a unique morphology characterized by a lack of traditional microvilli and a specialized basal pocket that houses immune cells such as dendritic cells and B cells (Neutra et al., 1996, Annual Review of Immunology). Their central biological role is the sampling of lumenal antigens and pathogens, which they transport via transcytosis from the apical surface to the underlying lymphoid tissue to initiate a targeted mucosal immune response (Hase et al., 2009, Nature). While critical for immune surveillance, M cells are frequently exploited as entry portals by various pathogens, including Salmonella typhimurium, Shigella, and Prions, which can lead to systemic infection (Ohno et al., 2009, Nature). In the context of drug development, M cells represent a significant target for the oral delivery of vaccines and macromolecular therapeutics, as they provide a unique pathway to bypass the degradative environment of the intestinal lumen (Azizi et al., 2010, Journal of Controlled Release). Current research focuses on utilizing M-cell-specific surface markers, such as Glycoprotein 2 (GP2), to direct vaccine-loaded nanoparticles or ligand-conjugated antigens for efficient mucosal immunization (Kanaya et al., 2012, Polymer Journal).

Other names

Microfold cellMembranous cellM-cellFollicle-associated epithelial cell

M cells facilitate the transport of lumenal antigens, particulate matter, and pathogens across the epithelial barrier via apical-to-basal transcytosis for presentation to underlying dendritic cells and lymphocytes.