Size of jejunal Peyer's patches and migration of lymphocyte subsets in pigs after resection or transposition of the continuous ileal Peyer's patch.

In pigs there are two types of Peyer's patches in the small intestine: discrete patches in the jejunum (jejPP) and a continuous patch in the terminal ileum (ilPP). The ilPP was resectioned or transposed into the upper jejunum. After the operation the size of the remaining jejPP showed no compensatory growth in either group within 10 months. However, the number of CD8+ lymphocytes in the blood, spleen, mesenteric lymph nodes, tonsils, and Peyer's patches and the number of CD4+ cells in the spleen and tonsils was reduced in comparison to those of age-matched control pigs. Autologous blood lymphocytes were labelled with fluorescein isothiocyanate and retransfused. In control animals the mid-portion of the ilPP showed a lower entry of lymphocytes and the migration pattern of lymphocyte subsets was different in the animals with resectioned or transposed ilPP as compared to controls. Thus, the removal of the ilPP (about 60% of all small intestinal PP) did not result in the remaining patches adapting their size, but it did influence other lymphoid organs.