Diphtherial Toxoid Purified by Absorption

In spite of numerous investigations conducted over a period of many years, detoxified crude bacterial filtrates are still commonly used in prophylaxis against diphtheria. Many attempts have been made to purify diphtherial toxin and toxoid, including experiments in absorption with calcium phosphate, but much remains to be learned. More information is required concerning antigenicity, reaction upon injection, and methods of manufacturing purified toxoid. At the present time, the crude fluid (bacterial filtrate) and alum-precipitated toxoids are used mainly for the immunization of children who can tolerate them better than adults. Crude toxoid prepared by detoxification of bacterial filtrates with formalin, in addition to proteins of true exotoxin, contains somatic antigens, i.e., soluble substances of proteinic nature that form precipitins with antibacterial serum. The biological significance of these substances and methods of their separation from the toxin have been discussed in our earlier publication (Parfentjev et al., 1942). It was shown that under controlled conditions selective absorption o