Fine Structure of the Dome in Peyer's Patches of Mice

Abstract
The dome area of Peyer''s patches in adult mice was studied by EM. The cellular constituents of the area are lymphocytes, plasma cells, macrophages and reticular cells. Macrophages are filled with numerous lysosomal bodies containing dead lymphocytes or plasma cells. The epithelium covering the dome is infiltrated with numerous lymphocytes, a few plasma cells and macrophages. These wandering cells 1st are found intercellularly but later appear to penetrate into the epithelial cell cytoplasm just beneath the cell apex. The epithelial cells containing the wandering cells in the supranuclear portion protrude into the intestinal lumen, and their microvilli are short and scanty. The epithelial cells covering the dome often have inclusion bodies containing dead wandering cells. Such modification of the epithelial cells may be related to the presence of underlying follicles. The dome including the covering epithelium is probably a site in which antigens from the intestinal lumen might come in direct contact with lymphocytes or other wandering cells.