Roles of Regulatory T Cells in Oral Tolerance and Food Allergy, pp. 99-116
Authors: (Yusei Ohshima, University of Fukui, Yoshida-gun Fukui, Japan)
Abstract: Gastrointestinal mucosa is an important site for oral tolerance induction and allergic responses to exogenous innoxious antigens, such as food antigens. The failure or aberration of oral tolerance results in the development of allergic diseases, especially food allergy. Several factors, including mucosal barrier function, humoral factors, lymphocyte anergy, clonal deletion, and regulatory T cells, contribute to the development of oral tolerance. Accumulating clinical and experimental evidences have suggested that the decreased number and dysfunction of regulatory T cells are involved in the pathogenesis of food allergy and that the development of regulatory T cells is associated with outgrowing food allergy. Although the precise nature of regulatory T cells controlling oral tolerance to food Ags remains unknown, recent reports demonstrate that not only regulatory CD4+ T cells but also subsets of CD8+ T cells may function as Treg by inhibiting allergic responses. Increased understanding of the mechanisms of oral tolerance has made a paradigm shift of therapeutic strategies for food allergies from avoidance of foods to oral tolerance induction by augmentation of regulatory T cells. In this article, we review the roles of regulatory T cells in oral tolerance and the pathophysiology of food allergy, and discuss their therapeutic potential.