FIG 3.
Bbvac confers robust protection for at least 15 months postvaccination. C57BL/6J mice were intranasally vaccinated with PBS (black) or PBS containing 5 × 105 CFU of Bbvac (red). Seven and 15 months after vaccination, mice were intranasally challenged with PBS containing 5 × 105 CFU of B. bronchiseptica (A, B, and C), B. pertussis (D, E, and F), or B. parapertussis (G, H, and I). Mice were euthanized 7 days postinoculation, and colonies were enumerated in the respiratory tract. Two-way ANOVA, Dunnett's multiple-comparison test. ***, P < 0.001; ****, P < 0.0001. Error bars represent standard error of the mean. n = 4 per strain and condition.