Figure 3.

IL-10⁺ B cells inhibit antigen specific CD4 T cells in a TLR7-dependent manner. Purified B cells were isolated from indicated genotypes and activated with LPS and anti-CD40 mAb for 36 h. Cells were pulsed with 5 μg/ml OVA peptide (323–339) for overnight. Purified OT-II CD4 T cells were CFSE labeled and co-cultured with peptide primed B cells in presence of OVA peptide for 96 h. (A,F) Representative flow plots show IL-10 expression in B cells after 48 h of co-culture. Representative contour plots (B,G) and bar diagrams (C,H) display IFN-γ expression in co-cultured CD4 T cells. (D,E,I,J) Representative histogram plots (D,I) show CD4 T cell proliferation by CFSE dye dilutions assay and the bar diagrams (E,J) show percentages of CFSE^lo CD4 T cells after 72 h of co-culture. (K) Histograms represent proliferation profile of CD4⁺ T cell that were co-cultured with activated B cells from indicated mouse strains in presence or absence of IL-10 neutralizing mAb. The numbers in the plots show percentages of CFSE^lo cells. The data shown are the cumulative results of 2–3 independent experiments. Statistical values were determined using an unpaired, non-parametric, Mann–Whitney, Student's t-test. *p < 0.05 and **p < 0.01.