Improved protection with PE/PPE boosting in BCG-primed mice.

<p>A) BCG priming and boosting protocol with PE/PPE-derived peptides. C57BL/6 mice (<i>n</i> = 6 per group) were injected with PBS or immunized s.c. with BCG. Two months later, mice were vaccinated twice s.c. at 10-days interval with individual or mixtures of PE/PPE-derived peptides formulated in CpG(DOTAP), followed by an i.n. administration of the same peptides. B) Expression of T-cell activation/migration/differentiation markers by the lung CD3⁺ CD4⁺ T cells of BCG-primed, PE/PPE-boosted mice at day 90. See furthermore <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1005770#ppat.1005770.s009" target="_blank">S8B and S8C Fig</a>. Mice were challenged 10 days after the last immunization (day 90) with ≈ 200 CFU/mouse of <i>Mtb</i> H37Rv WT strain via aerosol, as determined by day 1 post challenge by CFU counting in the lungs. One month post challenge, the mycobacterial loads were determined in the lungs (C) and spleen (D) of individual mice. NS = not significant, *, **, ***, **** = statistically significant, as determined by One Way ANOVA test with Tukey’s correction for multiple comparisons, <i>p</i><0.05, <i>p</i><0.005, <i>p</i><0.001 or <i>p</i><0.0001, respectively.