Significance of the absorption of macromolecules for the immune response of an organism

Numerous antigens are offered to the living organism by the daily food. Wit h these investigations the influence of orally administered human gammaglob ulin (HGG) on the immunity of sensitized animals after systemic immunizatio n should be clarified. Experiments were performed in rabbits. Changes of th e circulation were measured by bloodpressure registration and measurements of the organ flow. Simultaneous investigations of the antibody content, com plement C3 and histamin were performed in the peripheral blood. In orally f ed animals as well as in non fed controls an i.v. antigen challenge was per formed. The level of circulating antibodies could be significantly decrease d (60 %) by the oral administration of HGG. Tn control animals the parenter al antigen challenge resulted in a mortality rate of 50 %. In these animals the bloodpressure decreased significantly and long lasting. whereas antige n fed animals showed only a slight change in bloodpressure with normalizati on after a short period. During oral absorption of antigen complement facto r C3 remained unchanged. In the first hour after the oral antigen administr ation a significant increase of histamin in the peripheral blood could be o bserved. Investigation with regard to the fate of the antibodies which were decreased by antigen feeding showed a storage in the layers of the gut whi ch was depending on the dosage. It could be demonstrated that it is possibl e to influence the systemic immune response by the enteral application of m acromolecules and this is also relevant for reactions of the circulation.