ANTITUMOR EFFECT OF STREPTOCOCCUS-PYOGENES BY INDUCING HYDROGEN-PEROXIDE PRODUCTION

The Su strain of Streptococcus pyogenes (S-coccus) derived anticancer preparation, OK-432, which is immobilized by heating in the presence o f penicillin G, is well known to have an immunopotentiating activity t hrough activation of natural killer cells in vivo. In this study, a st reptococcal anticancer preparation stronger than OK-432 was prepared. Live streptococci (S-cocci) of the Su strain were induced to acquire H 2O2-producing ability by treatment with serum under aerobic conditions . The resulting preparation no longer possessed hemolytic activity, an d was not viable. The serum-treated S-coccus preparation activated nat ural killer cells as well as OK-432 did, and had stronger antitumor ac tivity than OK-432 did. These results suggest that the serum-treated S -coccus preparation would be a useful tool for chemotherapy, in additi on to immunotherapy, for the treatment of cancer.