Fig 3. Restoring PPE38-dependent protein secretion of BCG does not increase protection against M. tuberculosis in C57BL/6 mice.

Lung (A) or spleen (B) bacterial burdens of C57BL/6 mice infected with M. tuberculosis H37Rv via aerosol administration. Mice were vaccinated s.c. four weeks before the challenge, with 1 x 10⁶ CFU/mouse of either BCG or BCG38 (indicated in green). Both strains were prepared, either in standard culture conditions in medium containing 0.025% Tween-80 considered as no capsule (indicated with (-)), or in culture allowing capsule formation/retention in detergent free condition (indicated with (+)). Photographs of the assessed organs are depicted in S2A and S2B Fig. Each data point represents the CFU/organ of one single mouse counted and averaged from two technical duplicates. Error bars depict the standard deviation. Differences between different vaccination conditions were non-significant (p>0.05), but all vaccination conditions were statistically different from the unimmunized control group (p<0.01). For simplicity, this latter information is not depicted in the figure. Significance was calculated with Prism software using ordinary one-way ANOVA followed by Tukey’s test for multiple comparisons.