Extended Data Fig. 2: B cell activation is required for FDC expansion.
a) Quantification of the FDC network volume per LN based on anti-CD21/35 staining in clarified LNs from non-immunized (n = 8 mice) and 13 days post-immunized (n = 9) mice with IC-PE. b) Representative immunofluorescence images of LN B cell GCs from mice immunized for 14 days with IC-PE. Upper row shows the merged image of GL7 (yellow), IC-PE (magenta), and anti-CD21/35 (cyan) and the corresponding single-color images (gray). Yellow line demarcates GL7 staining and magenta line IC-PE localization (n = 4 mice). Lower row shows the merged image of anti-PD1 (yellow), IC-PE (magenta) and anti-CD21/35 (cyan) and the corresponding single-color images (gray). Yellow line demarcates PD1 staining and magenta line IC-PE localization (n = 4 mice). c) FDC numbers in non-transgenic C57BL/6 (WT; n = 5) and BCR-transgenic B1-8f (B1-8flox Igκ−/−; n = 6) and MD4 mice (n = 2) 24 hours after immunization with IC-PE. d) Representative confocal images of LNs from non-tg (WT), B1-8f and MD4 mice 24 hours after immunization with IC-PE (magenta). FDC networks are shown in cyan (anti-CD21/35). The white line delimits the edges of the organs. e) Percentage of GC B cells in non-immunized (light gray; n = 4 mice) and IC-immunized mice treated with anti-CD40L (orange; n = 8 mice) or isotype control antibody (black; n = 8 mice) as described in Fig. 2b. Quantitative data show means ± SD and analysis by two-tailed one-way ANOVA with multiple comparisons.
