Distribution of peanut agglutinin binding sites in rat lymphatic organs.

Distribution of peanut agglutinin binding sites was studied histologically with horseradish peroxidase labelled and fluorescein isothiocyanate labelled peanut agglutinin in terms of cell differentiation in rat lymphatic organs, (thymus, spleen, lymph nodes). In this study, alcohol-fixed paraffin-embedded tissue sections were used and proved to be useful for the histochemical study with peanut agglutinin. In the germinal center of the lymph node, cells were weakly positive for peanut agglutinin binding sites but not in the mantle zone of the lymph follicle. In the thymus, the cortical thymocytes were weakly positive for peanut agglutinin binding sites but not in the medulla. In the spleen, some cells on the periphery of the white pulp were weakly positive for PNA binding sites but cells around the central artery were not positive. Large cells with granular cytoplasma around the sinus of the spleen and lymph node, thought to be fixed macrophages, were strongly positive for PNA binding sites.