Lack of Antigenic Power of a Highly Purified Diphtheria Toxin and Detoxification by Ultraviolet Light

Abstract

The literature concerning the effect of ultraviolet radiation of toxins has been summarized by Norton 1 with the statement that “In the medium in which bacterial toxins are found or are produced they appear to be relatively stable toward ultraviolet light.” The work of Lowenstein, 2 and of Hortock, Schurman and Stiner, 3 which led to this conclusion, was done with the usual broth filtrates of organisms and in the case of diphtheria toxin from 6 hours to 20 days radiation was necessary to produce marked lessening of the toxicity of the filtrates. The former investigator was unable to produce an active immunity with radiated toxin. Although a previous investigation 4 had demonstrated the marked absorption of ultraviolet rays between 2000 and 3100 A° by proteins in solution or in suspension, it was thought advisable to determine whether the longer rays from “C” carbons (National Carbon Co.) would penetrate sufficiently to detoxify a broth filtrate of the diphtheria bacillus. Using the apparatus described in a previous article, 5 various dilutions of this toxic broth were radiated at varying distances and for varying periods of time, it was found that detoxification could be brought about but the long period of exposure necessary made it of little practical significance.

A water-clear, colorless diphtheria toxin prepared by the method of Gross 6 and with his aid, was found to be extremely toxic. Toxin prepared in this way contains but little protein. Since it had been found that the period of radiation necessary to insure detoxification varied directly with the potency of the toxin, a dilution of this toxin in physiological salt solution was selected for radiation, which gave a strong intracutaneous reaction in the guinea pigs.