Construction and expression of the complete Clostridium difficile toxin A gene in Escherichia coli

Abstract

Cloned fragments constituting the 8.1-kb toxin A gene of Clostridium difficile were used to reconstruct the intact gene. The recombinant toxin expressed in Escherichia coli was cytotoxic, enterotoxic, and lethal. In addition, toxic lysate caused hemagglutination of rabbit erythrocytes. The toxic activities were inhibited by antibody specific for toxin A. Our findings demonstrate that the biological activities exhibited by native toxin A are functions of a single protein encoded by the 8.1-kb toxin A gene, independent of any other C. difficile gene products.