Peyer's patches, gut IgA plasma cells and thymic function: study in nude mice bearing thymic grafts.

Nude mice have poorly developed Peyer's patches with very small or no germinal centers and little lymphoid cell proliferation, and a marked decrease in the number of gut-IgA plasma cells. Thymus grafts, which restore the T lymphocyte population of their lymphoid organs to nearly normal levels, lead to a considerable development of the Peyer's patches and of their germinal centers, assocaited with a considerable increase in gut IgA plasma cells, and in the serum IgA level. These findings are consistent with the postulated relationship between the Peyer's patches germinal center cells and the gut IgA plasma cells, and might help to explain the association of thymic defects, low serum IgA, and lack of intestinal IgA plasma cells observed in some immunodeficiency syndromes of man. Nude mice also have marked decrease in the number of lymphocytes present within the intestinal epithelium. These intraepithelial lymphocytes lymphocytes, which have been shown to be of T nature, are restored to normal numbers after thymus grafting.