Allogenic modification of rat sarcoma cells in vitro by staphylococcal exotoxin

The effect of toxin preparations from Clostridium welchii and Staphylococcus aureus on the growth of some experimental animal tumor cell lines was investigated. While clostridium toxin exerted considerable cytotoxicity, it did not influence either in vivo or in vitro growth of recovered cells. However, staphylotoxin treated sarcoma cells, while showing normal in vitro growth and metabolism, exhibited decreased growth rates when transplanted into susceptible hosts. This effect was demonstrable even after as many as 10 or more passages in vitro after the toxin treatment. Increased immunogenicity of staphylotoxin treated sarcoma cells was demonstrated by the complement-dependent serum cytotoxicity test. These results indicate that bacterial products, besides cytotoxicity and macrophage stimulation, may exert other effects upon tumor cells, for instance alteration of their immunogenicity and thus influence the tumor growth.