AbstractThe bacterial pathogenClostridium perfringensis the most prolific toxin-producing species within the clostridial group. The toxins are responsible for a wide variety of human and veterinary diseases, many of which are lethal.C. perfringenstype A strains are also associated with one of the most common forms of food-borne illness (FBI). The toxicosis results from the production and gastrointestinal absorption of a protein-enterotoxin known as CPE. The regulation, expression, and mechanism of action of CPE has been of considerable interest as the protein is unique. CPE expression is sporulation associated, although the mechanism ofcpe-gsne regulation is not fully elucidated. Cloning studies suggest the involvement of global regulators, but these have not been identified. Although very few type A strains are naturally enterotoxigenic, thecpegene appears highly conserved. In FBI strains,cpeis chromosomally encoded; whereas in veterinary strains,cpemay be plasmid-encoded. Variation incpelocation suggests the involvement of transposable genetic element(s). CPE-like proteins are produced by some C.perfringenstypes C and D; and silent remnants of thecpegene can be found in C.perfringenstype E strains associated with the iota toxin gene. CPE has received attention for its biomedical importance. The toxin has been implicated in sudden infant death syndrome (SIDS) because of its superantigenic nature. CPE can destroy a wide variety of cell types bothin vitroandin vivo, suggesting that it could have potential in the construction of immunotoxins to neoplastic cells. It is obvious that CPE is an interesting protein that deserves continued attention.