Clostridium perfringens exotoxins. III. Binding of theta-toxin to erythrocyte membrane.

When Clostridium perfringens theta-toxin was incubated with sheep erythrocytes the toxin activity disappeared before lysis, the fact of which suggests fixation of the toxin to erythrocyte membranes. 2. Theta-Toxin lost its activity by binding to cell membranes, and the membrane constituted inhibitor of theta-hemolysis was neither a protein, a carbohydrate nor a phosphatide, but was cholesterol. From these results this report proposes that the theta-toxin binding site of erythrocytes should be cholesterol.