A preliminary report on bone transplantation. 1. An immunohistochemical study on the distribution and proportions of lymphocyte subsets in lymphoid organs of normal rats.

Abstract

Although the rat is often used in experiments on bone transplantation, very few immunohistochemical studies on the distribution and proportions of lymphocyte subpopulations and subsets in rat lymphoid organs have been performed, in comparison with other animals. A preliminary immunohistochemical investigation using the immunofluorescence and avidin-biotin-peroxidase complex methods was therefore undertaken to clarify this aspect in various lymphoid organs taken from rats.The results obtained were as follows : 1. Ia-positive cells largely indicative of B cells were localized in the lymphoid follicles of lymph nodes, follicular areas of Peyer's patches and non-periarteriolar lymphatic sheath (PALS) areas of the spleen.2. T cells were densely distributed in the lymphoid pulp of lymph nodes, interfollicular areas of Peyer's patches and PALS areas of the spleen.3. Helper T-and asialo GM1-positive cells were localized in the lymphoid pulp of lymph nodes, interfollicular areas of Peyer's patches and spleen red pulp. The numbers of positive cells with these phenotypes were smaller than those of Ia-and pan T-positive cells.4. These results indicate that the distribution and proportions of lymphocyte subpopulations and subsets in rat lymphoid organs are generally similar to those of other animals such as the mouse.