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. 2016 May 2;213(5):715–732. doi: 10.1084/jem.20151722

Figure 7.

Figure 7.

B cell–intrinsic IFN-γR stimulus drives GC differentiation through STAT1, but not STAT3, phosphorylation. (A) Flow cytometric analysis of intracellular STAT1, pSTAT1, and pSTAT3 expression (by mean fluorescence intensity) in B220+PNAFas non-GC B cells and B220+PNAhiFashi GC B cells. These data represent five mice per group in three replicate experiments. (B and C) Flow cytometric analysis of intracellular pSTAT1 (B) and pSTAT3 (C) expression (mean fluorescence intensity) in B220+ cells after treatment of purified B cells with IFN-γ in vitro for the indicated time points. These data represent five mice per group in three replicate experiments. (D) Flow cytometric analysis of intracellular pSTAT1 expression (MFI) in B220+ cells with and without treatment of B cells with IgM alone, IFN-γ alone, or both IgM and IFN-γ in vitro for 10 min. These data represent five mice per group in three replicate experiments. (E) Flow cytometric analysis of percentages of B220+FashiPNAhi GC B cells and CD4+CXCR5hiPD-1hi Tfh cells in 6-mo-old mice. (F) Representative histological images of spleen sections from 6-mo-old B6 and B6.STAT1−/− mice (five mice per group) stained with the GC B cell marker GL7, anti-CD4, and anti-IgD. (G) Flow cytometric analysis of the percentages of GC B cells and Tfh cells. (H) Representative histological images and quantification of GC structures of spleen sections from 3-mo-old B6.STAT1fl/fl and CD19Cre/+STAT1fl/fl mice (six mice per group). (I) Maintenance of ex vivo–generated GC B cell phenotype of B cells obtained from B6.STAT1fl/fl and CD19Cre/+STAT1fl/fl mice in the presence of IFN-γ. (J) Flow cytometric analysis of intracellular T-bet expression in GC B cells described in H. (K) Quantitative RT-PCR analysis of IFN-γ transcripts in GC B cells treated with IFN-γ as described in H. For H–J, n = 3 per group in three replicate experiments. In B and C, statistical analysis was performed by one-way ANOVA with a follow-up Tukey multiple-comparison test. Otherwise, statistical values were determined using an unpaired, nonparametric, Mann–Whitney Student’s t test. Error bars are mean ± SD. *, P < 0.05; **, P < 0.01; ***, P < 0.001. Bars: (F) 150 µm; (H) 75 µm.