Suppression of antibody formation by the reticuloendothelial (RES)-blockade. I. Effects of the RES-blockade with macromolecular polyvinyl pyrrolidone

For the purpose of revealing the role of the reticuloendothelial system (RES) for the antibody formation, the rats which received the repeated intraperitoneal and subcutaneous injections of a vast amount of PVP were challenged by bovine serum albumin (BSA) introducing through 2 routes of intramuscular and intravenous, and then antibody formation was observed. Blood cell count and clearance rate of radiogold were observed for the purpose of obtaining the information of blockade grade of the RES by PVP. Phagocytic activity of macrophages ingesting PVP against iron colloid were also observed in vitro. 1. A severe anemia was induced by the administration of a vast amount of PVP, 15 ml of 3% solution daily or every other day for 63 days. Histological picture indicated the suppressed erythropoiesis probably by iron deficiency or the lowered iron transporting activity of the RES, as the anemia recovered after intraperitoneal iron injections. 2. With the generalized and marked swelling of the RES, the cells in germinal center of spleen and lymph nodes were extremely swollen and lymphocytes disappeared completely, suggesting that the macrophages in germinal center play an important role in reproduction and differentiation of lymphocytes. 3. The phagocytic activity of the RES as understood from the clearance rate of radiogold was suppressed only slightly even by a heavy deposition of PVP after the repeated injections. The state of blockade or the suppressed phagocytic activity persisted for 48 hours or more after the several PVP injections. However, complete blockade of the RES or inactivation of the phagocytic activity by PVP injection was not attained. 4. A prolonged treatment of animals with PVP caused delay in the appearance of circulating antibody but the final titration reached the same level as that of control. The data suggest that the blockade of the RES by PVP induces the delay in the transmittance of the information for the antibody formation from the macrophages to the immunologically competent cells but no delay in the ingesting antigen by the macrophages.