Fig. 5.

T-bet is essential for Th1-like Tfh cell differentiation and IgG2c antibody class switching. a–d Wild-type (WT) mice and Tbx21^−/− mice were infected by ZIKV with anti-IFNAR1 blocking antibody. Splenocytes were collected for measurement of Tfh cell on 7 dpi and antibody-producing B-cell responses on 14 dpi, and sera were collected for antibody responses on 14 dpi (n = 3–5 for each group). a Representative flow cytometry plots of CXCR5^highPD-1^high cells and CXCR5^mediumPD-1^medium in CD4⁺CD44^highCD62L^low T cells were presented as Tfh cells and pre-Tfh cells (left panel); bar graphs summarized the percentages and numbers of cells in each group. b Representative flow cytometry plots of IFN-γ staining in CD4⁺CD44^low naive cells, CXCR5^medium PD-1^medium pre-Tfh cells and CXCR5^highPD-1^high Tfh cells (left panel); the percentages of IFN-γ⁺ cells in each group were summarized in bar graphs (right panel). c Representative flow cytometry plots of IgM, IgG1, IgG2b, and IgG2c staining of IgD^low B cells (left panel); bar graphs summarized the percentages and numbers of cells in each group. d The concentrations of ZIKV envelope specific IgM, IgA, total IgG, IgG1, IgG2b, IgG2c, and IgG3 antibodies were measured by ELISA. The summary data were presented as mean ± SEM. Statistical differences were determined by Student’s t test and p values were indicated by **p < 0.01, or ***p < 0.001. Data shown represent two (d) or at least three (a–c) independent experiments. Source data are provided as a Source Data file