Figure 6.

Cytokine response. Heat-inactivated pertussis (hBp) and individual solutions of the antigens PT, FHA, and PRN (obtained from GC and prepared to their vaccine concentrations of 25 μg/mL, 25 μg/mL, and 8 μg/mL, respectively) were cultured for 72 h with single splenocytes collected from the spleen at 8 weeks (3 weeks after boost vaccination) and 1 and 2 weeks post-infection (p.i.) with pertussis (ATCC 9797). After culture, the supernatant was collected, and cytokine ELISA kits (Proteintech) were used to measure the levels of IFN-gamma, IL-5, and IL-17a for each group (n = 5). To prepare heat-inactivated pertussis, the bacteria were adjusted using McFarland standards to a concentration of 1 × 10⁶ CFU/mL, suspended in pH 7.4 PBS, and heated at 65 °C for 30 min. (a) hBP-stimulated IFN-gamma secretion; (b) hBP-stimulated IL-17a secretion; (c) hBP-stimulated IL-5 secretion; (d) PT-stimulated IL-5 secretion; (e) FHA-stimulated IL-5 secretion; (f) results for PRN-stimulated IL-5 secretion. All results are presented as the means ± standard errors of the means (SEM). Statistical differences were investigated using one-way ANOVA and Bonferroni’s post hoc test. p values are as follows: * p < 0.05, ** p < 0.01, *** p < 0.001, **** p < 0.0001. MV, mock vaccinated.