Fig. 4

S. aureus vesicles inhibit macrophage efferocytosis. A A schematic diagram of efferocytosis/phagocytosis assays using BMDMs fed CFSE-labeled apoptotic thymocytes or EGFP-E. coli bioparticles. B Representative histograms illustrate fluorescence. C Efferocytosis rate (% of CFSE⁺ cells/control) of different bacterial vesicle-treated BMDMs. D Efferocytosis under various concentrations of SAVs. E Immunofluorescence analysis and representative images depicting quantification of engulfed thymocytes (red: actin; blue: nucleus; green: thymocytes) and merged images. CFSE-labeled thymocytes containing BMDMs (White triangles). The efferocytosis index represents the percentage of CFSE⁺ cells. Scale bar = 200 μm. F Efferocytosis of SAVs-treated peritoneal macrophages and BMDMs. G A protocol for SAVs/PBS treatment of thioglycolate-induced peritonitis mice. Representative histograms were shown, and the efferocytosis rate was calculated using F4/80^high CD11b^high macrophages (n = 3 mice/group/experiment). Data represent mean ± SEM from triplicates done in two independent experiments. One-way ANOVA with Bonferroni’s multiple comparison test and unpaired two-tailed t-test. *, p < 0.05; **, p < 0.01; ***, p < 0.001 (compared to the control group)