Figure 3.

Optimal germinal center response requires T-bet expressed in TFH cell. WT and Tbx21^−/− mice were infected with LCMV. Spleens were harvested at day 8 post infection. (A) Representative Immunofluorescent staining of splenic B cell follicular with GL-7 (green), anti-IgD (blue), and anti-CD4 (red). (B,C) Representative flow cytometry of GC B cells (FAS⁺PNA⁺) (B) and plasma cells (CD138⁺B220^low) (C) (left) with its percentages (right) in WT and Tbx21^−/− mice. (D) Representative flow cytometry of IgG2c⁺ plasma cells (left) with its percentages (right) in WT and Tbx21^−/− mice. Numbers adjacent to outlined areas indicate percent of each cell subset in parent subset. (E,F) Serum of WT and Tbx21^−/− mice were collected and tested for anti-LCMV IgG (E) and anti-LCMV IgG2c (F) by enzyme-linked immunosorbent assay (ELISA). ^*P < 0.05, ^***P < 0.001, ^****P < 0.0001 (unpaired two-tailed t-test). Data are representative of two independent experiments with 3–5 mice per group (error bars, SEM).