Recombinant expression of in silico identified B-cell epitope of epsilon toxin of Clostridium perfringens in translational fusion with a carrier protein

Abstract

Epsilon toxin secreted by Clostridium perfringens types B and D has been directly implicated as the causative agent of fatalenterotoxemia in domestic animals. The aim of the present study is to use in silico approach for identification of B-cell epitope(s) ofepsilon toxin, and its expression in fusion with a carrier protein to analyze its potential as vaccine candidate(s). Using differentcomputational analyses and bioinformatics tools, a number of antigenic determinant regions of epsilon toxin were identified. Oneof the B cell epitopes of epsilon toxin comprising the region (amino acids 40-62) was identified as a promising antigenicdeterminant. This Etx epitope (Etx40-62) was cloned and expressed as a translational fusion with B-subunit of heat labile enterotoxin(LTB) of E. coli in a secretory expression system. Similar to the native LTB, the recombinant fusion protein retained the ability topentamerize and bind to GM1 ganglioside receptor of LTB. The rLTB.Etx40-62 could be detected both with anti-Etx and anti-LTBantisera. The rLTB.Etx40-62 fusion protein thus can be evaluated as a potential vaccine candidate against C. perfringens.