title: Gastrointestinal transport of macromolecules in the pathogenesis of food allergy.
abstract: In this presentation we have reviewed current concepts of antigen (allergen) transport within the gastrointestinal tract. We have shown that luminal antigens must cross the mucosal barrier before attaching to the intestinal microvillus surface. Uptake into the systemic circulation requires pinocytosis and diffusion across the lamina propria into the intravascular space. Several immunologic and non-immunologic defenses help to control and regulate the uptake of intestinal antigens. These include intestinal flora, peristalsis, the gastric barrier, mucus release from goblet cells, hepatic filtration and proteolysis. In many instances, immune complexes, particularly SIgA-specific complexes, stimulate the non-immunologic host defenses to function more effectively. Secretory antibodies therefore act to provide both exclusion of antigens by physical interference with antigen penetration and by augmentation of non-immunologic defenses. Figure 6 depicts the concept of antigen uptake under normal (physiologic) conditions and with altered intestinal host defenses.
mesh_terms: D000818:Animals; D000941:Antigens / Q000378:metabolism; D001692:Biological Transport; D004064:Digestive System / Q000378:metabolism* / Q000382:microbiology; D005512:Food Hypersensitivity / Q000209:etiology*; D005753:Gastric Mucosa / Q000378:metabolism; D005769:Gastrointestinal Motility; D007408:Intestinal Absorption; D007419:Intestinal Secretions; D008099:Liver / Q000276:immunology; D046911:Macromolecular Substances; D051381:Rats; D013270:Stomach / Q000276:immunology
chemical_list: D000941:Antigens; D046911:Macromolecular Substances