The lymphoid system and immunologic defense of the digestive tract

摘要: Lymphocytes and macrophages are distributed in the intestinal tract as isolated cell populations epithelium lamina propria present focal aggregates forming lymphoid follicles. Ultrastructural investigation has played a major role understanding cellular interactions cytoarchitectural details critical to function of mucosal immune system (1–3). The tissue tract, which includes that oral cavity, pharynx, Peyer’s patches, appendix, follicles small large intestines, represents substantial fraction elements make up system. Collectively, these immunologic structures, termed gut-associated tissues (GALT), surface area variety potential antigens respond highly coordinated fashion during recognition foreign molecules pathogens. distribution cells reflects varying antigen load different regions intestine. Lymphoid is prominent oropharynx, minimal esophagus stomach, where rapid transit time acid secretions reduce antigenic burden, becomes abundant again distal intestine intestine, stasis promotes bacterial proliferation.