Recombinant vaccinia viruses protect against Clostridium perfringens alpha-toxin.

Recombinant vaccinia viruses that expressed the nontoxic C-domain of Clostridium perfringens alpha-toxin were constructed. The J2R (thymidine kinase [TK] gene) and B13R (serpin 2 [SPI-2] gene) loci were used as insertion sites for the clostridial DNA, and expression of the foreign protein was measured in each case. A double recombinant that encoded the alpha-toxin truncate at the B13R locus and the protective antigen of Bacillus anthracis at the J2R locus was also constructed. Although differences in expression of the alpha-toxin C-domain were recorded, all of the vaccinia recombinants protected mice against a lethal challenge with alpha-toxin demonstrating that a recombinant vaccinia virus can be used to provide protection against a toxin challenge that is known to be solely antibody mediated.