Food allergens and the mucosal immune system

摘要

In Japan, allergic disease affect's 30 percent of the population and 10 percent of infants are reported to experience adverse reactions to food. Food allergy is often the first manifestation of allergic disease in young allergic patients. The clinically important allergen sources in food are eggs, milk, legumes, seafood, cereals, meat, and occasionally others. Food allergy, triggered by an aberrant immune response elicited by orally ingested food allergens, is generated through a complicated mechanism because the allergen interacts with the mucosal immune system. Information on the regions on food allergens recognized by T cells and antibodies, which are the T and B cell epitopes respectively, is important for understanding the fates of food allergens after being recognized by the mucosal immune system. The structure of the T and B cell epitopes on food allergens and suppression of allergic reactions by amino-acid substituted analogs of allergen-derived peptides will also be described. Orally administered antigens induce distinct immune responses in the Peyer's patches, the lamina propria and the intestinal epithelium. In addition to these local immune responses in the gut, ingested antigens are known to affect systemic immunity. These may induce a suppressed state of systemic immune responsiveness, which is called oral tolerance. The breakdown of oral tolerance results in the occurrence of a systemic IgE antibody response which may lead to allergic reactions. Recent studies have shown that induction of oral tolerance is an effective method for treatment of allergy.