Iota Toxin, S Toxin and CDT: Members of the Same Class of Clostridial Binary Toxins in Feces of Humans and Other Animals

Abstract

Some strains of Clostridium perfringens, Clostridium spiroforme and Clostridium difficile produce binary toxins known respectively as iota toxin, S toxin and CDT. Each toxin consists of two unlinked polypeptides (e.g. CDTa and CDTb) that only together have biological activity. Taking an historical perspective, we review the development and early use of assays employing the specific neutralization of a biological activity for the detection and quantification of binary toxin. The survey moves on to more recent immunological assays and culminates with a discussion of the relevance of binary toxin, especially CDT, in feces.