FIG 8.

Serum-mediated inhibition of bacterial adherence. Pools of sera from mice immunized with CS6-based vaccine candidates (n = 8 to 10/pool) were assayed for the quantification of anti-CS6 functional neutralizing antibodies in an HT-29–CS6⁺ ETEC in vitro assay. Pools were prepared with day 42 sera from mice immunized with CS6 protein and monomers and dimers of CS6 subunits (evaluated in the first mouse experiment), CS6 protein and trimers of the CS6 subunits (evaluated in the second mouse experiment), and redesigned dimers of CS6 subunits (evaluated in the third mouse experiment). In the same assay, a pool of sera from PBS-immunized mice was also assayed, and the results from that pool were used to normalize the results as 100% binding (“zero” inhibition; 1.81 × 10⁶ ± 0.54 × 10⁶ CFU bacteria recovered [means ± SD]). Bars indicate intraexperimental means ± SD of data from evaluations performed in triplicate. *, P < 0.05 (compared to CS6 [first study]).