ABSTRACT
This chapter summarizes information about cytolytic toxins. All cells have plasma membranes that act as a barrier between the internal environment of the cell and the extracellular fluid. It follows, therefore, that all cells are potential targets for cytolytic toxins. Cytolytic toxins are produced from a wide range of sources: bacteria, fungi, plants, sea anemones, insects, fish, and snakes. A number of plant constituents have cytolytic properties that probably result from their surfactant actions. The major class of cytolytic toxins whose mechanism of action is unknown is a group of protein toxins from cobra venoms. Streptolysin O is a toxic immunogenic protein released in the extracellular medium by most strains of group A and many strains of group C and G Streptococci , particularly those causing human infections. The cytolytic factor was a protein with a molecular weight of about 80,000 daltons and an isoelectric point of around 5.0. Streptolysin S is a very potent cytolytic toxin produced by Streptococci.
