Boosting PPE10 specific immune responses does not increase protection against <i>M</i>. <i>tuberculosis</i>.

<p>A) Graphical representation of the prime-boost vaccination protocol. Mice were immunized with either BCG or BCG38 (Green). 60 days post-infection (d.p.i.) C57BL/6 x CBA F1 mice were injected s.c. with a booster consisting of adjuvant CpG(DOTAP), alone or in combination with a mix of PPE10_221-235 and PPE10_381-395 peptides (blue). The same formulation was intranasally administered four weeks later. Nine days after the intranasal boost, mice were exposed to <i>M</i>. <i>tuberculosis</i> H37Rv aerosol infection (220 CFU/lung 1 d.p.i). Bacterial lung (B) and Spleen (C) burdens were assessed by dilution and counting 4 weeks post-infection (experimental end-point) after being photographed for macroscopic investigation (<a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1007139#ppat.1007139.s002" target="_blank">S2C and S2D Fig</a>). Each data point represents the CFU value of one organ from a single mouse, error bars depict the standard deviation. No significant differences between the vaccination conditions were detected by ordinary one-way ANOVA followed by Tukey’s test of multiple comparisons. All vaccination conditions resulted in a significant (<i>p</i><0.01) reduction in lung burden compared to unimmunized controls (Ordinary one way ANOVA; Dunnett’s test of multiple comparisons against a single control). For simplicity, this latter information is not depicted in the figure. Reduction in spleen CFUs was not significant for any of the vaccination conditions. Statistical analyses were performed using PRISM software.