[Immunoregulation by the gut-associated immune system].

The gut associated immune system plays a special regulatory role within the immune system. It governs not only the local IgA response of the gastrointestinal tract but, moreover, gives rise to an antigen specific systemic immune tolerance after enteral application of antigens. This systemic tolerance is suggested to be mediated by lymphatic cells as well as by soluble factors, such as antibodies, immune complexes and suppressor factors, respectively. Very recently published data suggest the existence of an antigen specific, lymphocytic contrasuppressor circuit, which interacts with the well known helper- and suppressor systems within Peyer's plaques thus simultaneously allowing for a local immune response and a systemic tolerance.