A recombinant carboxy‐terminal domain of alpha‐toxin protects mice against Clostridium perfringens

Clostridium perfringens alpha‐toxin (CP, 370 residues) is one of the main agents involved in the development of gas gangrene. In this study, the immunogenicity and protective efficacy of the C‐terminal domain (CP251‐370) of the toxin and phospholipase C (PLC; CB, 372 residues) of Clostridum bifermentans isolated from cases of clostridium necrosis were examined. The recombinant proteins were expressed as glutathione S‐transferase (GST) fusion proteins. Antibodies that cross‐reacted with alpha‐toxin were produced after immunization with recombinant proteins including GST‐CP251‐370, GST‐CP281‐370, GST‐CP311‐370, CB1‐372 and GST‐CB251‐372. Anti‐GST‐CP251‐370, anti‐GST‐CP281‐370 and anti‐GST‐CP311‐370 sera neutralized both the PLC and hemolytic activities of alpha‐toxin, whereas anti‐CB1‐372 and anti‐GST‐CB251‐372 weakly neutralized these activities. Immunization with GST‐CP251‐370 and GST‐CP281‐370 provided protection against the lethal effects of the toxin and C. perfringens type A NCTC8237. Partial protection from the toxin and C. perfringens was elicited by immunization with GST‐CP311‐370 and CB1‐372. GST‐CP251‐370 and GST‐CP281‐370 are promising candidates for vaccines for clostridial‐induced gas gangrene.