Potential protective immunogenicity of recombinant Clostridium perfringens α-β2-β1 fusion toxin in mice, sows and cows.

Clostridial toxins are main pathogenic virulence of Clostridium perfringens that have been associated with a wide range of diseases in both humans and domestic animals. Genetically engineered toxoids have been shown to function as potential vaccine candidates in the prevention of Clostridium derived infectious diseases. In this study, we have developed recombinant α-toxin (CPA), β2/β1-fusion toxin (CPB2B1) and α/β2/β1 trivalent fusion-toxin (CPAB2B1) as vaccine candidates that may be used to vaccinate against C. perfringens α, β1 and β2-toxins. Mice immunized with these recombinant toxoids demonstrated a strong protective immunological response when administered a lethal dose of C. perfringens type C culture filtrate with high titers of neutralizing antibodies to the toxins in the sera, as well as the intestinal mucosal s-IgA level. Specific neutralizing antibodies to the toxins were also detected in the sera and colostrum of sows and cows vaccinated with the toxoids. Furthermore, the CPA and CPB2B1 recombinant toxoid cocktail was capable of stimulating relatively higher levels of immune responses compared to that of CPA, CPB2B1 and CPAB2B1 alone. The CPAB2B1 trivalent fusion toxoid also displayed increased immunogenicity relative to CPA and CPB2B1 alone. These results suggest that recombinant toxoids are potential vaccine candidates against Clostridial toxins; the use of mixed cocktails and/or multivalent recombinant toxoids against different types of toxins may be an effective approach in the prevention of diseases caused by toxins produced by C. perfringens.