FIG. 10.
Effect of neutralizing antibodies on binding and transcytosis of BoNT/A. Toxin (1 × 10−8 M) was incubated alone or with BAL samples (0.1 ml) or antiserum (0.1 ml) obtained from mice that had been immunized with BoNT/A HC50 vaccine. After incubation (1 h), the solutions were added to apical wells containing monolayers of epithelial cells, and transcytosis was monitored. The results demonstrated that untreated toxin crossed epithelial barriers (lane 1) but antibody-pretreated toxin did not cross these barriers (lane 2, antiserum; lane 3, BAL sample).