The use of oral tolerance as a therapy for ocular autoimmunity

Mucosal surfaces throughout the body are the main protective structures against the heavy antigen burden from the environment. The ability to distinguish between noxious agents that should be kept in check and innocuous or beneficial substances that should be ignored is one of the most interesting phenomenon in immunology. Oral tolerance is the phenomenon by which exposure to a soluble antigen through the mucosal surface results in subsequent inability to mount an immune response to the same antigen upon challenge by a different route. This type of tolerance-inducing mechanisms has been recognized for many years as an effective approach to induce peripheral tolerance to soluble proteins. Recent achievements in the use of oral tolerance in the treatment of autoimmune diseases are reviewed here. Special emphasis is placed on the use of this immunotherapeutic approach to uveitis. The role of cytokines, CD4+ cells, CD8+ cells, as well as the putative mechanisms by which oral tolerance is induced, are discussed.