Recombinant vaccinia viruses that expressed the nontoxic C-domain of Clostr
idium perfringens alpha-toxin were constructed. The J2R (thymidine kinase [
TK] gene) and B13R (serpin 2 [SPI-2] gene) loci were used as insertion site
s for the clostridial DNA, and expression of the foreign protein was measur
ed 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 a
lpha-toxin C-domain were recorded, all of the vaccinia recombinants protect
ed mice against a lethal challenge with alpha-toxin demonstrating that a re
combinant vaccinia virus can be used to provide protection against a toxin
challenge that is known to be solely antibody mediated.