Figure 5.

IgA of nasal lavage fluid and bacterial clearance of lungs. After three rounds of vaccination, we measured IgA levels in nasal lavage fluid (1:1 diluted with PBS) for each antigen at 8 w and at 2 h and 1, 2, and 6 weeks post infection (p.i.). All results are presented as the mean ± standard errors of the mean (SEM) of the OD₄₅₀ values for five animals per group. We also investigated the levels of bacteria (CFU) in lung tissue from mice challenged with the same method at 2 h, 5 days, and 1 and 2 weeks p.i. (a) PT., (b) FHA., (c) PRN., (d) Lung homogenate was serially diluted ten-fold with casamino acid solution and cultured in charcoal agar for at least 5 days in a CO₂ incubator before measuring the CFU. Between-group differences were investigated using one-way ANOVA and Bonferroni’s post hoc test, and p values are displayed as follows: * p < 0.05, ** p < 0.01, *** p < 0.001, **** p < 0.0001. CFU, colony-forming unit; MV, mock vaccinated.