M Cells: Specialized Antigen Sampling Cells in the Follicle-Associated Epithelium

摘要: Microfold (M) cells are epithelial specialized for antigen sampling that found within follicle-associated epithelium covers mucosal lymphoid structures including intestinal Peyer's patches and isolated follicles. Intestinal M readily distinguished from other enterocytes by their characteristic ultrastructural features short blunted microvilli invagination of the basolateral membrane forms an intraepithelial pocket. can take up particulate antigens such as bacteria soluble gut lumen incorporating them into vesicular form at apical surface. These vesicles subsequently transcytosed toward cell's membranes where contents released pockets. Differentiation uncommitted crypt requires RANKL, a tumor necrosis factor superfamily cytokine selectively produced subepithelial stromal cells. cell uptake environmental sites facilitates transport across preferential delivery inductive tissues adaptive immune responses initiated.