[The significance of Peyer's plaques for intestinal immunity. Animal experimental inferences]

The removal of Peyer's patches alters the first line of defence against a known bacterium. Whereas in control animals all reactive cells could be found within the lamina propria of the gut, in rats without Peyer's patches only small amounts of IgA and IgM secreting cells could be detected there. In contrast IgA and IgM secreting cells could be found within mesenteric lymph nodes and spleen. The removal of the Peyer's patches diminishes the reaction of the lamina propria. Therefore other lymphatic structures like mesenteric lymph nodes and spleen get contact with antigenic material and generate E. coli specific immune globulin secreting cells. These cells were able to secrete IgA which was detected within the bile. This compensatory mechanism helps to restore the disturbed balance. The consequence of the systemic reaction against the E. coli must be discussed in view of cross reacting antibodies or the generation of inflammatory cells within the gut.