Cytotoxic and cytolytic action of the subcellular fraction (60-F) of live hemolytic streptococci against Ehrlich ascites carcinoma cells.

The cytotoxic effect of 60-F, a subcellular fraction obtained from 0.5 approximately 0.6 saturation of cell-free extract of live hemolytic streptococci (Su-strain) with ammonium sulfate on Ehrlich ascites carcinoma cells was studied by the assay of incorporation of nucleosides and amino acid, and by the in vitro-in vivo cytocidal experiment. Additionally, the cytolytic effect of 60-F was examined by the assay of RNA and DNA released from the tumor cells. It was found that the tumor cells treated with 60-F did not take up thymidine, uridine, or leucine, that 60-F eradicated the transplantability of tumor cells in mice, and that 60-F released RNA but not DNA from the tumor cells.