The relationship of macrophages and erythrocyte receptors to vascular patterns in vole spleen.

The spleens of two species of voles were studied to determine the relationship between arterial terminals, macrophages and antibody-mediated erythrocyte receptors. The vascular distribution was studied by vascular injections and by use of PAS-stained serial sections. Macrophages were identified by their positive metalophil and hydrolytic enzyme reactions and their ability to phagocytose carbon. Antibody-mediated erythrocyte receptors were localized and studied by using combined erythrocyte binding, and an acid phosphatase technique. White pulp capillaries and penicillate arteries branch from the central arteries. Some white pulp capillaries terminate in the reticular meshes of the marginal zones and some in funnel-shaped dilatations continuous with the marginal sinuses. These apertures and extensions of the perifollicular rings extend to the germinal centers. Penicillate arteries can be traced to the red pulp cords. Macrophages were found in the following locations: (1) between the coronary regions and marginal zones (marginal metalophils); (2) in germinal centers, (3) in marginal zones, and (4) in red pulp cords. Sheep erythrocytes bind over the macrophages of the germinal centers, over the marginal metalophils and over macrophages of the marginal zones. These bound erythrocytes lyse when incubated with complement. These results illustrate that there are marginal metalophils other than rats, and that erythrocytes binding over sections of spleen are associated with the white pulp macrophages. The germinal centers of vole spleen have several characteristics that are associated with white pulp compartments that are involved in generation of primary antibody responses.