[Immunological tolerance]

Immunological tolerance refers to the ability of not reacting by immunological defense reactions when they are not needed. It does not mean a mere lack of response but rather continuous active controlling and modifying of initiated responses towards tolerance. While tolerance is primarily a property of the adaptive immune system, it is also influenced by the innate immune system. The importance of tolerance is emphasized in the intestinal immune system, where foreign structures are present in abundance. In fact, orally administered antigens may in the future hopefully be utilized for the treatment of diseases caused by harmful immune responses.