IFN-γ signaling is required for LD formation during <i>M</i>. <i>tuberculosis</i> infection <i>in vivo</i>.

<p><b>(A-J)</b> Mice were infected with ~200 CFU of <i>M</i>. <i>tuberculosis</i> via the aerosol route and lungs were collected for histological analysis of LD formation by Oil Red O (ORO) staining. (A-D) ORO stained lung sections from wildtype and <i>Ifng</i>^-/- mice 21 days post-infection. Sections were counter-stained with hematoxylin. (E-J) ORO stained lung sections from wildtype (E,F), <i>LysMcre</i>^<i>+/+</i><i>; Hif1a</i>^<i>fl/fl</i> (G,H), and <i>Hig2</i>^-/- mice (I,J) at 28 days post-infection. (K) ORO signal as a percentage of lesion area was quantified in sections from wildtype, <i>LysMcre</i>^<i>+/+</i><i>; Hif1a</i>^<i>fl/fl</i>, and <i>Hig2</i>^-/- mice. (L) Bacterial burden in the lungs of wildtype and <i>Hig2</i>^-/- mice was enumerated by plating for CFU at 1, 18 and 28 days post-infection. Images and figures are representative of at least 3 independent experiments. Error bars are standard deviation, *p<0.05, **p<0.01 by unpaired t-test.