Fig. 4: IFN-I aggravates LM infection by directly inhibiting neutrophil swarming.
From: Inhibition of neutrophil swarming by type I interferon promotes intracellular bacterial evasion
a–c Mice were subjected to HDI with 5 μg pLive or pLive-IFNβ plasmid 5d prior to infection. a Representative intravital images showing neutrophil clusters in the liver 24 h post-infection with 1 × 106 CFU LM-GFP. Scale bar, 200 μm. b Quantification of the size of neutrophil clusters, with each dot representing an infection focus. Data were from three mice in each group. (P < 0.0001). c Bacterial load in the liver was assessed at 48 h post-infection with 1 × 106 CFU LM-GFP. Data were from four mice in each group. (P = 0.0268). d WT and Ifnar−/− mice were infected with 1 × 106 CFU LM-GFP. Representative intravital images showing neutrophil clusters in the liver at 24 h post-infection with 1 × 106 CFU LM-GFP. Scale bar, 100 μm. e WT and Ifnar−/− mice underwent SpX. Representative intravital images showing neutrophil clusters in the liver at 24 h post-infection with 1 × 106 CFU LM-GFP. Scale bar, 100 μm. f Quantification of the size of neutrophil clusters, with each dot representing an infection focus. Data were from three mice in each group. (P < 0.0001). g Illustration of the procedure for bacteria AGAR pellet imaging. h Bacteria AGAR pellet imaging was conducted to visualize neutrophil swarming with and without IFN-β1 treatment. Scale bar, 200 μm. i Quantification of neutrophil cluster size at 150 min post-imaging, with each dot representing a neutrophil cluster. The experiment was repeated twice and statistically analyzed. (P = 0.0284). Data are represented as mean ± SEM. *P < 0.05; **P < 0.01; ***P < 0.001.
