Lymphocyte subpopulations in high endothelial venules and lymphatic capillaries in rat Peyer's patches: An immunoelectron microscopic study.

Abstract

The subpopulations of recirculating lymphocytes in both high endothelial venules (HEV) and lymphatic capillaries surrounding follicles in Peyer's patches (PP) were examined by electron microscopy of ultrathin sections after pre-embedding immunoperoxidase technique. Monoclonal mouse anti-rat T cell, IgG, IgM and IgA sera were used. Plasma cells which were reactive to anti-IgG, -IgM and-IgA were detected as cells with 3, 3′-diaminobenzidine tetrahydroxychloride (DAB) reaction in rough endoplasmic reticulum and perinuclear spaces, but not on plasma membranes. These plasma cells were not seen in either lymphatic capillaries or HEV. Cells containing surface Ig (sIg cells) and T cell antigen (T cells) and were observed as cells with electron dense plasma membranes. The percentages of T, sIgG, sIgM and sIgA cells in the HEV were 69.4%, 3.8%, 10.2% and 11.4%, respectively, and in the lymphatic capillaries, 47.2%, 8.1%, 21.6% and 33.6%, respectively.The results indicate that the largest common lymphocyte subpopulation in both HEV and lymphatic capillaries surrounding follicles in PP is T cells, followed by sIgA and sIgM cells.