Heterogeneities of two components of C2 toxin produced by Clostridium botulinum types C and D.

Botulinum C2 toxin (C2T) is composed of two dissimilar protein components, designated components I and II, which are linked with neither covalent nor noncovalent bonds. The heterogeneity of these two components of C2T produced by Clostridium botulinum type C and D strains was examined. Of 21 strains examined, 19 strains produced the two components, while the others produced neither component I nor component II. The 19 producers of C2T could be divided into three groups based on the differences in antigenicity, molecular weight and biological activity of components I and II. The results provide evidence of heterogeneity in the molecular structure of the two components of C2T, which is possibly a cause of the differences in the biological activity of the toxin observed in different strains.