The Effect of Foreign Protein on the Blood and Reticuloendothelial System of the Hamster

The injection of human plasma into hamsters over a period of 14 to 68 days induced splenomegaly, accompanied histologically by reticuloendothelial hyperplasia, plasmacytosis, increased erythropoiesis and hemosiderosis. These findings suggest both an antigen-antibody response and an abnormal increase in splenic hemolysis. The demonstration of positive erythroagglutination reactions when red cells from plasma-injected hamsters are tested also suggests an immunologic response by these animals. Mild anemia was present in some animals during the course of this study but at the termination of the experiment anemia was not present and the animals were apparently in a compensated state. It is clear that the reticuloendothelial system of the hamster is capable of responding to foreign protein. Apparent immunologic tolerance in this animal should not be attributed to inactivity of the reticuloendothelial system.