Antigens in Immunity

Abstract

Details of the trapping of antigens in the spleen of rats were studied. Rats received Intravenous or subcutaneous injections of Salmonella flagellar antigens labelled with 1125. They were killed at intervals and autoradiographs of spleen sections were performed. The antigen localization pattern was contrasted with the distribution of colloidal carbon. The study involved 132 rats. The autoradiographs showed progressive movement of antigen from red pulp to marginal zone, across the marginal sinus, into the white pulp and finally into the outer aspect of the germinal center. With pure protein antigens, loss of label from red pulp and marginal zone was rapid and complete. Antigen never penetrated into the area of white pulp immediately surrounding the central arteriole. The results suggested purposeful movement of discrete antigen-carrying cells. The localization of carbon was less selective. A minor degree of movement to the germinal center occurred but red pulp and marginal zone did not clear. Carbon was scattered diffusely throughout the whole white pulp, reaching areas never apparently exposed to antigens. The relevance of the findings to problems in the induction of antibody formation is discussed.