The fate of 3H-SPG administered to sarcoma-180 grafted mice

Schizophyllan (SPG) is reported to have an excellent host-medicated antitumor action. In this study, 500 mg of SPG was exposed to 15 Ci 3H-gas for 2 weeks, and 184 mCi/3H-SPG was obtained. Finally, 132 μCi/mg (specific activity) of purified 3H-SPG was obtained. Sarcoma-180 grafted ICR-mice were used in this experiment. As a pretreatment, 1 mg per Kg body weight of cold SPG was administered interperitoneally 4 times at 3-day intervals. 400 μCi/head of 3H-SPG was injected intravenously 4 days after the last cold SPG administration. 24 hrs after the 3H-SPG injection, the mice were anesthetized with Nembutal, and parts of the liver, spleen, bone marrow, lung, lymph nodes and the tumor were prepared for microscope autoradiography. 3H-SPG had accumulated in the ''reticuloendothelial cell cytoplasm'', including macrophages throughout the body, from which it can be concluded that SPG may activate the antitumor antigen production in the T-cells and macrophages in the tumor, directly or indirectly. (Auth.)