Studies on the Adsorption of Diphtheria Toxin to and Elution from Magnesium Hydroxide

Abstract

Summary: An improvement on the purification of diphtheria toxin by adsorption to colloidal magnesium is reported. Whereas, the original toxic broth contained 37 mgm. of dried materials per gram the purified toxin contained only 0.17 mgm. of total solids per gram. The raw toxin gave 3.4 antigenic units per cubic centimeter. Neither the purified toxin, nor its filtrate or a mixture of the two, although each contained about 32 antigenic units per cubic centimeter, were capable of immunizing rabbits and guinea pigs. “Le pouvoir antigène intrinsèque” of Ramon (the neutralizing power of the toxin toward antitoxin as determined by the flocculation method) being the true indicator of antigenicity does not hold for a toxin purified by adsorption to colloidal magnesium.