Vaccination with recombinant whole heavy chain fragments of Clostridium botulinum Type C and D neurotoxins.

Mice and ducks were subcutaneously immunized with recombinant whole heavy (H) chains of Clostridium botulinum type C and D neurotoxins, which were expressed as glutathione S-transferase fusion proteins. In the case of mice, it was confirmed that two immunizations with type C- and D-H chains, 10 microg each time, significantly increased the specific antibodies against 100-kDa H chains of type C and D neurotoxins in an immunoblot analysis and an enzyme-linked immunosorbent assay, respectively. The mice immunized with type C- and D-H chains showed no symptoms of botulism when they were challenged with C- and D-16 S toxins at doses, given intraperitoneally, of up to 10(5) and 10(6) minmum lethal doses (MLD), respectively, per mouse. Ducks were immunized with a total of 100 microg of type C-H chain. The ducks also developed specific antibodies to the type C-H chain and showed significant protection against a challenge with 10(3) duck MLD of C-16 S toxin given intravenously. These results indicate that recombinant whole H chains can be used as an effective and safe vaccine for type C and D botulism in domestic animals.