Fig. 5

MHC-II⁻S100A9⁺ monocytes exert immunosuppressive function on T cell immunity. Monocytes from spleen of WT or S100a9^−/− mice undergoing CLP surgery for 72 h were isolated, followed by co-culture with CD3/CD28 activated naïve CD4⁺ T cells isolated from unmanipulated murine spleens. Supernatants and CD4⁺ T cells were assayed after 3 d of coculture. a Histogram with quantitative bar plot exhibited and compared the proliferative activity of naïve CD4⁺ T cells cocultured with monocytes in each group based on CFSE assay. b Contour plots with quantitative bar chart revealed the proportion of CD4⁺CD25⁺Foxp3⁺ Tregs. c Quantitative bar charts showed levels of IL-2, IL-4, IL-10, and IFN-γ in the cocultured supernatants, with ratio of IFN-γ to IL-4. Two-way ANOVA with Tukey HSD test was used to determine the statistical significance between groups. Data are shown as means ± SD. ^*P < 0.05, ^**P < 0.01, ^***P < 0.001, ^****P < 0.0001. MHC major histocompatibility complex, WT wild-type, CLP cecal ligation and puncture, CFSE carboxyl fluorescein succinyl ester staining, Tregs regulatory T cells, IL interleukins, IFN-γ interferon-γ, ANOVA analysis of variance, SD standard deviation