High-affinity, protective antibodies to the binding domain of botulinum neurotoxin type A

Monoclonal antibodies (MAbs) were prepared against the putative binding dom ain of botulinum neurotoxin A (BoNT/A), a nontoxic 50-kDa fragment. Initial ly, all fusion products were screened against the holotoxin BoNT/A and agai nst the binding fragment, BoNT/A H-C. Eleven neutralizing hybridomas were c loned, and their specific binding to BoNT/A H-C was demonstrated by surface plasmon resonance, with dissociation constants ranging from 0.9 to <0.06 n M. Epitope mapping by real-time surface plasmon resonance showed that the a ntibodies bound to at least two distinct regions of the BoNT/A H-C fragment . These MAbs will be useful tools for studying BoNT/A interactions with its receptor, and they have potential diagnostic and therapeutic applications.