<i>Gp130^F/F</i> mice display dramatic susceptibility to infection with <i>M. tuberculosis</i>.

<p><i>Gp130^F/F</i>, <i>gp130^F/F Il-6^−/−</i>, <i>gp130^F/F/Stat3^+/−</i> and control mice were sacrificed 4 weeks after aerosol infection with <i>M. tuberculosis</i>, and CFU per lung assessed (A). The CFU in lungs of individual mice and the median per group (n≥6) are depicted. <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1003442#s2" target="_blank">Results</a> are pooled from two independent experiments. Differences in CFU are significant (*p&lt;0.05, ***p&lt;0.001 Mann Whitney U test). A gross-pathology photograph of the lungs from <i>gp130^F/F</i>, <i>gp130^F/F Il-6^−/−</i> and control mice 4 weeks after infection with <i>M. tuberculosis</i> is shown (B). <i>Gp130^F/F</i>, <i>gp130^F/F Il-6^−/−</i> and control mice were sacrificed at 4 weeks after <i>M. tuberculosis</i> infection and the total RNA was extracted from lungs. The accumulation of <i>Il-6</i> (C) and <i>Il-12 p40</i> (D) transcripts was measured by real time PCR. The mean fold cytokine mRNA increase ± SEM in lungs from infected mice (n = 5 per group) are depicted. Differences with controls are significant (**p&lt;0.01 Student t test). 2×10⁶ CD90+ <i>gp130^F/F</i> and control splenic T cells were inoculated i.v. into <i>Rag1^−/−</i> mice. Two weeks after transfer, mice were infected via the aerosol route with <i>M. tuberculosis</i>. Mice were sacrificed 4 weeks after infection and the CFU in lungs determined. The median CFU (n≥10) in lungs, quartiles and the 99^th percentiles are depicted (E). <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1003442#s2" target="_blank">Results</a> are pooled from two independent experiments. Differences in CFU are significant (**p&lt;0.01, ***p&lt;0.001 Mann Whitney U test). The CFU in lungs of <i>gp130^F/F</i> bone marrow→WT and WT bone marrow→ WT radiation chimeric mice were measured one month after infection with <i>M. tuberculosis</i>. A box and whisker diagram showing the median CFU (n≥8), quartiles and the 99^th percentiles is depicted (F). Differences in CFU are significant (***p&lt;0.001 Mann Whitney U test).