Migration pattern of lymphocyte subsets in the normal rat and the influence of splenic tissue.

Lymphocyte subsets leave the blood and appear in the thoracic duct of normal rats at different rates. The aim of the present study was to investigate their migration pattern through blood, spleen, bone marrow, mesenteric lymph nodes, and Peyer's patches in normal Lewis rats and to study the role of the spleen using splenectomized and spleen-transplanted animals. Fluorescein isothiocyanate (FITC)-labelled thoracic duct lymphocytes (TDL) were injected intravenously into rats and after 15 min, 1, 6, and 24 h the percentages of B, T, T helper (TH) and T-cytotoxic/suppressor (TC/S) lymphocytes in the FITC+ cells were determined in cell suspensions by means of monoclonal antibodies. B and T lymphocytes are preferentially localized in different organs, e.g. B cells in Peyer's patches and T cells in mesenteric lymph nodes. The migration of TH lymphocytes differed from that of TC/S lymphocytes in all the organs investigated. In the late phase after injection the migration of B and TH lymphocytes was influenced by the spleen, since after splenectomy the number of injected B lymphocytes increased and that of TH lymphocytes decreased in all organs investigated except the bone marrow. Splenic autotransplantation could not normalize the disturbed migration.