Statistical analysis of a rapid in vivo method for the titration of the toxin of Clostridium botulinum

Significance of 12S toxin of Clostridium botulinum type E

The pathogenesis of type E botulism is discussed as an aspect of the physicochemical and biological properties of 12S toxins (prototoxin and trypsin-activated 12S toxin) and the Ealpha and Ebeta components of each 12S toxin. A molecular weight of 350,000 was determined for each 12S toxin and 150,000 for Ealpha and Ebeta. Owing to the structure comprising the subunits Ealpha and Ebeta, 12S toxins are much more stable than Ealpha at low pH values and high temperatures. Such was also the case with type A 19S toxin and its alpha component. The Ealpha component alone accounts for the total toxicity of type E toxin. The toxic substance detected in the blood of the animals administered 12S toxins orally or parenterally was identified as Ealpha from the molecular size and the chromatographic pattern. Prototoxin escaping from detoxification in the stomach owing to the subunit structure may undergo dissociation in the intestine to release the Ealpha component. After absorption, the activated Ealpha appeared in the circulating blood without any further signs of dissociation or enzymatic digestion.

Homogeneity and molecular weight of toxin of Clostridium botulinum type B

Gerwing et al. described the isolation and purification from culture filtrates of the toxin of Clostridium botulinum type B and characterized it as a homogeneous protein of less than 10,000 molecular weight. Analysis by various methods of samples of this toxin obtained from Gerwing et al., and preparations produced by their methods in our laboratories, furnished convincing evidence that neither her preparation nor ours was homogeneous. The molecular weight of the toxic component isolated from either of the preparations was 100,000 or greater and resembled, in a number of respects, the alpha component isolated by us from the crystalline toxin of C. botulinum type A.