Role of Peyer's patch in the intestinal immune response to cholera toxin in enterically immunized rats

Cholera toxin has been widely used to obtain insight into the cellular dynamics of the antigen-specific mucosal immune response. The present study was undertaken to clarify the influence of the organized intestinal lymphoid tissue (Peyer's patches [PP]) on the distribution of anti-cholera-toxin-containing cells (ACC) after intraperitoneal immunization and intraduodenal challenge with purified cholera toxin. This was done in rats which were surgically deprived of all visible PP. In comparison with sham-operated animals, each PP-deprived rat had nearly the same amount of ACC in the spleen, the mesenteric lymph nodes, and, surprisingly, the thoracic duct lymph. In contrast, the ACC in the duodenum, the jejunum, and the ileum of each PP-deprived animal were drastically reduced. Therefore the PP are suggested as an important organizing structure for the buildup of a local antigen-specific immune response.