Preparation of egg yolk antibodies against BoNT/B and their passive protection in mouse models.

Botulism in human is a devastating intoxication caused mainly by type A, B, and E botulinum neurotoxins (BoNTs). The most effective treatment of botulism is injection of BoNT antiserum in the first 24 h. In this study, a recombinant C-terminal heavy chain of BoNT/B (BHc) was successfully expressed in E. coli. The soluble BHc was used as an antigen to immunize laying hens for yolk immunoglobulin (IgY) production. The purified IgY against BHc subunit, preincubated with the BoNT/B, was predominantly involved in the neutralization of BoNT/B toxicity. Furthermore, both intraperitoneal and intragastric administration of the IgY could protect mice from death caused by injection of toxin at a lethal dose. Our results therefore suggest that anti-BHc IgY directed to the Hc domain is effectively involved in the neutralization of BoNT/B toxin and may be considered as preventive and therapeutic intervention in the case of botulism.