Mechanisms of Tolerance Induction in Food Allergies

Abstract

The mechanisms of tolerance induction in food allergies involve the establishment of oral tolerance along with the development of digestive and mucosal barrier functions. When food antigens are degraded to amino acids, their antigenicity disappears and no immune response is elicited. The mucosal barrier is composed of mucus, intestinal epithelial cells, immunoglobulin A, and antimicrobial peptides that block the entry of antigens in the intestinal tract. Oral tolerance is a physiological phenomenon that suppresses the immune response to antigen recognition in the gastrointestinal tract, and is modulated by antigen-presenting cells, regulatory T cells, and inhibitory cytokines. Besides the intestinal tract, the liver and tonsils are other organs that induce immune tolerance; the intestinal microbiota also contributes to the induction of immune tolerance. The mechanisms of oral immunotherapy are complex, involving both acquired and innate immunity, and negative regulation of the immune response by regulatory T cells and interleukin-10 are particularly important. High doses of antigens induce clonal anergy but may enhance intestinal inflammation and allergic reactions and interfere with tolerance. Therefore, more detailed mechanisms must be elucidated to optimize oral immunotherapy protocols and develop new therapies.