Isolation of the Lethal Factor of Diphtheria Toxin by Electrophoresis in Starch Gel

Abstract

HIGHLY purified toxins of Corynebacterium diphtheriae have been shown to be very complex mixtures by antigen–antibody diffusion in gelatin¹. In spite of their apparent homogeneity as determined by filter paper electrophoresis, one of us demonstrated the complex nature of such toxins by electrophoresis and immunoelectrophoresis in starch gel². All the crude, as well as the crystalline, toxins (a generous gift of Dr. C. G. Pope) screened by these methods (Poulik, in preparation), have invariably shown the presence of two major components in addition to many minor ones. Since diphtheria toxin is lethal in very high dilutions for guinea pigs, it was assumed that it is most probably one of the two major components which is the cause of death.