Type I IFNs regulate the phenotype and effector functions of Mo/Mϕ in IAV-infected lungs.

<p><b>(A)</b> Representative flow plots demonstrating Ly6C^hi or Ly6C^lo mononuclear phagocyte populations and histograms depicting the expression of surface molecules on Ly6C^hi or Ly6C^lo cell subsets in the lungs of d7 infected WT and <i>Ifnar1</i>^—/—mice (n = 7 mice / genotype). The flow cytometry data shown are gated on CD11b⁺CD4^—CD8^—B220^—NK1.1^—Ly6G^—SiglecF^—cell populations. <b>(B)</b><i>Nos2</i> expression in lungs of infected mice determined at d7 p.i. using qRT-PCR. Data shown are mean fold increases (relative to uninfected controls) ± SD. Data were pooled from 3 independent experiments (n = 6–9 mice / genotype). <b>(C)</b> Representative flow plots of intracellular NOS2 expression in the lungs of infected WT and <i>Ifnar1</i>^—/—mice at d7 p.i.. The flow cytometry data shown are gated on live, singlet cells. Flow plots are representative of 3 independent experiments with n = 6–9 mice / genotype. <b>(D)</b> Percentage and number of NOS2-positive mononuclear cells in the lungs of infected WT and <i>Ifnar1</i>^—/—mice quantified using flow cytometry. Data were pooled from 3 independent experiments with a similar trend and are mean levels ± SD (n = 6–9 mice / genotype). <b>(E)</b> Representative flow plots depicting NOS2 present in Ly6C^hi and Ly6C^lo cells. The flow cytometry data shown are gated on CD11b⁺CD4^—CD8^—B220^—NK1.1^—Ly6G^—SiglecF^—cell populations. <b>(F)</b> Paired analysis of percentage and mean fluorescence intensity (MFI) of NOS2 in Ly6C^hi and Ly6C^lo populations in WT and <i>Ifnar1</i>^—/—mice at d7 p.i.. Data were pooled from 3 independent experiments and each paired data set represents an individual mouse. Statistical analyses were performed using paired Student’s <i>t</i>-test.