The Expression of Cytokeratins in Bovine Intestinal Microfold (M) Cells

The mucosal surface of the gut is exposed to a variety of foreign antigens and microorganisms, some of which are potentially harmful for the host. To protect against the risk of infection, the intestinal mucosa has developed specialized organized lymphoid tissues and epithelial cells. The gut-associated lymphoid tissues (GALT) including Peyer’s patches (PPs) are major inductive sites for intestinal immunity. Different from other peripheral lymphoid tissues, GALT lacks afferent lymphatics, and directly samples mucosal antigens across the epithelial barrier to initiate antigen-specific immune responses. This task is accomplished by specialized epithelial cells within the follicle-associated epithelium (FAE) covering the lymphoid follicles of GALT known as microfold (M) cells.