A non-toxic recombinant protein rSUMO-CPBm4 as a potential vaccine candidate against Clostridium perfringens type C beta enterotoxemia.

Abstract

Beta toxin (CPB) is a lethal toxin and plays a key role in enterotoxemia of ruminants caused by Clostridium perfringens type C strain. The existing vaccines based on crude CPB need time-consuming detoxification and difficult quality control steps. In this study, we synthesized the rCPBof C. perfringens type C strain and small ubiquitin-like modifier (SUMO)-tag CPB(rSUMO-CPB) by introducing four amino acid substitutions: R212E, Y266A, L268G, and W275A. Compared with rCPB, rSUMO-CPBwas expressed with higher solubility in Escherichia coli BL21 (DE3). Neither rCPBnor rSUMO-CPBwas lethal to mice. Although rCPBand rSUMO-CPBwere reactogenic with polyclonal antibodies against crude CPB, rabbits vaccinated with rSUMO-CPBdeveloped significant levels of toxin-neutralizing antibody (TNA) titers that conferred protection against crude toxin challenge. These data suggest that genetically detoxified rSUMO-CPBis a promising subunit vaccine candidate for C. perfringens type C beta enterotoxemia.