Studies on the Exotoxin of Hemolytic Streptococci Animal C

Abstract

A toxic substance was demonstrated in the liquid culture filtrate of Animal C streptococci belonging to the C group hemolytic streptococci. it caused death in mice, induced reddening, swelling and induration of rabbits' skin when injected intracutaneously, reduced its toxicity by heat and was inactivated in a short time, when preserved at 37°C in a weak-alkaline medium with additional formalin. Rabbits' serum obtained after repeated intravenous injection of the substance effected neutralisation of the toxin. These results indicated an exotoxic nature of the substance. This substance per se or the toxoid prepared by an in activation procedure with formalin could actively immunize mice when injected repeatedly, and thus protected them in a certain limit from an attack with living cocci.