Figure 2.

Protection of mice against B. pertussis infection induced with the OMVs vaccine compared with wP and aP vaccines. C57BL/6 mice were immunized (i.p.) twice, 4 weeks apart, with either wP, aP, or OMVs vaccines or were non-immunized. Mice were challenge 2 weeks after the second immunization by aerosol with B. pertussis BP338 strain (1 × 10⁸ CFU/ml) administered using a nebulizer (PARI TurboBOY SX) over 10 min. Results are shown as the number of bacteria recovered from the mouse lungs at different time points, expressed as the log₁₀ of the means ± SEM (error bars) of the CFUs per lung, plotted on the ordinate for the samples from the lungs of the experimental groups indicated on the abscissa. The experiment involved three biological replicates with the results from a representative one being presented. The dotted horizontal line marks the lower limit of detection. ^***p < 0.001 (ANOVA followed by the Bonferroni post-hoc test).