Splenectomy Exerts No Appreciable Influence Upon Immunity against Transplanted Tumors

Abstract

If the lymphocytes be the important agent in the production and distribution of immunity to transplanted tumors, as is asserted by Da Fano, Murphy, and others, it is not improbable that the spleen, a lymphocyte-forming organ, may take some part in the process. In an experiment previously reported (1), it was shown that the removal of the spleen of normal rats, either before or after inoculation with tumor, had no effect upon the growth energy, the percentage of takes, or the percentage of spontaneous absorption of the tumors. The present paper records additional experiments showing the lack of influence of the spleen upon certain phases of tumor growth and immunity. Our first experiment confirms an observation of Brancati (2) that splenectomy does not influence the persistence of immunity in animals. Twenty-four rats bearing rat sarcoma 7, a tumor which is spontaneously absorbed, and which produces concomitant immunity in from 90 to 100 per cent of inoculated animals after three weeks9 growth, were splenectomized one week after the complete absorption of their tumors. One week after operation, these animals and 24 control rats were inoculated with 0.003 gram of the same tumor strain. The operated animals showed 100 per cent immunity, while the 24 controls showed but 4 per cent.