1. CCR2+ monocytes are a relevant source of type I IFN in response to Af.
CCR2+ monocytes are a relevant source of type I IFN in response to Af. (A and B) IFNAR−/− (green), IFNLR1−/− (blue), double-deficient IFNAR−/−IFNLR1−/− (DKO; purple), and WT control (black) B6 animals were challenged with 4 × 107 CEA10 Af conidia and examined for type I IFN expression at 12 hours after infection (A) or type III IFN at 48 hours after infection (B) by ELISA. (C to G) CCR2+Ly6C+ monocytes (red bars), CD45+ cells depleted of monocytes (hatched bars), and CD45− pulmonary cells (gray bars) were isolated from the lung of CCR2-GFP reporter mice at 3 hours (C, E, and G) or 48 hours (D and F) after infection with Af. Pulmonary, CCR2+Ly6C+ monocytes were also isolated from naïve CCR2-GFP reporter mice (white bars). All samples were examined for IFN transcription (C, D, and G) or secretion of IFN proteins (E and F) after overnight ex vivo culture. (H) Endogenous transcription of type III IFN was examined by qRT-PCR in RNA samples isolated from the lungs of CCR2-depleted mice that were left untreated (red) and in CCR2-depleted mice that were treated with 1 μg of IFN-α (green), 1 μg of IFN-λ (blue), or 1 μg each of IFN-α and IFN-λ (purple). Responses in CCR2+ competent littermates (black) were used as positive controls. DT, diphtheria toxin. Data are means ± SEM for four mice per group and for one experiment representative of two. *P < 0.05; **P < 0.01; ****P < , calculated by Mann-Whitney nonparametric test of experimental group relative to WT control mice using Prism software.
Vanessa Espinosa et al. Sci. Immunol. 2017;2:eaan5357
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