[The mechanisms of oral tolerance].

Oral or nasal administration of a single high dose or repeated mucosal delivery of low doses of proteins have been shown to induce systemic unresponsiveness in the presence of mucosal IgA responses. The induction of oral tolerance(or mucosally-induced tolerance) is mediated by T cells involved in the generation of active suppression, clonal anergy or clonal deletion. Studies of T helper(Th) cytokine responses have suggested that Th1- and Th2-type cells are involved in the induction of oral tolerance. Further, gamma delta T cells appear to be an important T cell subset for the regulation of oral tolerance.