FIG. 3.

Binding of BoNT/A monoclonal antibodies to BoNT/A1 and BoNT/A2 toxins as determined by capture ELISA. Wells were coated with the indicated MAb followed by various concentrations of pure or complex BoNT/A1 or BoNT/A2. Toxin binding was detected using polyclonal equine BoNT/A antisera. A1 toxins are indicated by solid squares; A2 toxins are indicated by open circles. Pure toxins are solid lines; toxin complexes are dashed lines. Differences in binding signals for MAbs C25 and B4 between A1 and A2 pure and complex toxins may reflect the presence of different sets of accessory proteins (reference 30 and see the text).