In the last two decades, physicians have become more aware of the spleen's role in natural immunity. The spleen is composed of two distinct but interrelated compartments. Fixed phagocytes of the reticuloendothelial system (RES) reside in the red pulp while lymphoid tissue is found in the follicles and periarteriolar sheaths of the white pulp. These two anatomic divisions are reflected in the spleen's two separate immunologic functions. On the other hand, the spleen serves as an important organ of clearance of hematogenously borne bacteria in the nonimmune host.1 On the other hand, it plays an important role in the production of early antibody in response to particulate antigens circulating in the bloodstream.2 It is the strategic location of these two separate functions "midstream" in the circulation that accounts for its unique role in the nonimmune host's defense against blood-borne bacteria.
A number of studies in animals have documented