Figure 3. Prophylactic vaccination with H28 and H56 result in similar levels of protection.

Groups of CB6F1 mice were vaccinated three times with two weeks interval with H28 or H56 formulated in CAF01 or with CAF01 alone. (A) Two weeks following vaccination with either H28 or H56, PMBCs (pooled from six mice) were stimulated with Ag85B, TB10.4, ESAT-6 or Rv2660c and antigen specific responses assessed by flow cytometry. The frequency of cytokine producing CD4 T cells expressing IFN-γ, IL-2 or both cytokines was determined by intracellular staining for cytokines (ICS). Lung lymphocytes (pooled from six mice) were obtained after six weeks of infection and the frequency of cytokine producing CD4 T cells determined by ICS. Data are representative of three experiments. (B) Protection was assessed at week 6 post infection by culturing lung homogenates and enumerating bacteria (expressed as log₁₀). Data displayed are box and whiskers of six mice and minimum and maximum CFU levels. As a negative control, a group of mice received CAF01 only. Values marked with an asterisk are significantly different from naïve control animals as assessed by ANOVA and subsequent Tukey’s multiple-comparison test (***, p<0.001). The data are typical for several experiments as illustrated in Table S1.