Figure 3.

CysVac2-induced protection against pulmonary M. tuberculosis infection correlates with the generation of multifunctional CD4⁺ T cells. C57BL/6 mice (n=5) were vaccinated with BCG (s.c., 5×10⁵ CFU) or three times s.c. with 3 μg CysVac2, Ag85B or CysD formulated in MPL/DDA. Twelve weeks after the first vaccination, the mice were challenged with ~100 CFU of M. tuberculosis by aerosol route and the bacterial load assessed in the lung assessed 4 weeks later (a). The data are presented as Log₁₀ of the mean of CFU±s.e.m. (b) The protective efficacy of CysVac2 was assessed across five individual experiments and a meta-analysis of Log₁₀ protection of vaccinated compared with unvaccinated mice shown. (c) Representative dot plots of CD4⁺ lung T cells restimulated ex vivo with CysVac2 in the presence of brefeldin A and detection of intracellular IFN-γ, IL-2 or TNF. (d) The frequency of CysVac2-specific multifunctional CD4⁺ T cells in the lung was also determined. (e) The frequency of CysVac2-specific CD4⁺ T cells producing IL-17 in the lung. The proportion of CD4⁺ IL-17⁺ T cells expressing combinations of IFN-γ, IL-2 and/or TNF is shown in the pie chart (see d for cytokine subsets). The significance of differences between the groups was determined by one- or two-way analysis of variance (ANOVA) (*P<0.05, **P<0.01; ***P<0.001; NS, not significant). Data are representative of at least two independent experiments.