Type I IFN and IFN-γ signaling synergize to inhibit neutrophil trafficking to IAV-infected lungs.

<p><b>(A)</b> Representative flow plots depicting lung Ly6G⁺ neutrophil populations. The flow cytometry data shown are gated on CD11b⁺CD4^—CD8^—B220^—NK1.1^—SiglecF^—cell populations. <b>(B)</b> The percentage of neutrophils in WT, <i>Ifnar1</i>^—/—, <i>Ifngr1</i>^—/—or <i>Stat1</i>^—/—mice determined by flow cytometry at d7 p.i.. <b>(C)</b> The number of neutrophils in WT, <i>Ifnar1</i>^—/—, <i>Ifngr1</i>^—/—or <i>Stat1</i>^—/—mice determined by flow cytometry at d3 (red circles) and d7 (black circles) p.i.. Data were pooled from 2 independent experiments. <b>(D)</b> Percentage of Ly6G⁺ neutrophils in the blood and lungs of infected mixed BM chimera mice. The mixed CD45.1⁺ (WT) and CD45.2⁺ (<i>Ifnar1</i>^—/—) BM chimeric mice were generated, infected and analyzed using flow cytometry as described in <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1005378#ppat.1005378.g002" target="_blank">Fig 2D</a>. The data show the percentage of Ly6G⁺ neutrophils among CD45.1⁺ (WT) or CD45.2⁺ (<i>Ifnar1</i>^—/—) cells in the blood or lung of infected mixed BM chimeric mice at d7 p.i.. Data are representative of 2 independent experiments (n = 10–14 mice / study). <b>(E)</b> mRNA expression of <i>Cxcl1</i> and <i>Il1b</i> in lungs analyzed using qRT-PCR at d7 p.i.. Data shown are mean fold increases (relative to uninfected controls) ± SD. Data were pooled from 3 independent experiments with a similar trend. In <b>B</b>, <b>C</b> and <b>D</b>, circles denote individual mice and bars represent group means.