Figure 4
Boosting with BCG in the nApa subunit vaccine-primed mice does not impart a stronger booster effect.
(a) The magnitude and kinetics of cytokine-producing cells in the i.n. mucosal nApa vaccinated mice. Mice were immunized three times with nApa (10 μg/dose) in a DDA-MPL adjuvant at 2-week intervals by the i.n. route and the nApa-specific IFN-γ, IL-2, IL-4 and IL-17 responses were investigated in the lung and spleen (pooled) as indicated using a cultured ELISPOT assay (n = 4 mice/time point). Data are mean ± s.d. of triplicate cultures using cells. Significantly decreased responses at week 32 compared to the 2-week time point using a one-way ANOVA and Bonferroni correction. **P < 0.01 and ***P < 0.001. (b) Schematic representation of the prime–boost vaccination protocol. Mice were immunized three times with the nApa-DDA/MPL vaccine as described in (a). Eight months after the last subunit dose, a group of subunit-vaccinated and age-matched naïve mice received a single BCG vaccine-boost (106 CFU) by a homologous i.n. route. Three weeks following a BCG-boost, mice (n = 4/group) were sacrificed and the cellular immune response was investigated. (c,d) Frequencies of (c) nApa- and (d) WCL-specific IFN-γ, IL-17 and IL-4-producing cells in the lung and spleen (pooled) using a cultured ELISPOT assay. Data are mean + s.d. of triplicate cultures. Significant using the ANOVA and Bonferroni correction relative to the respective control group. A numbers in the parenthesis indicates a fold change in the total SFU in BCG-boosted group over levels in the respective control group. i.n., intranasal; vac, vaccine; WCL, whole cell lysate of Mtb; SFU, spot forming units.
