Fig. 3

Reduced numbers of mature B cells in BAFF E247K knock-in mice despite normal circulating level of BAFF competent for receptor binding. a Relative levels of circulating BAFF were measured in a homogeneous ELISA-like assay (AlphaLisa) using a pair of anti-mBAFF antibodies (5A8 and Sandy-2) in the serum of Baff^wt/wt (+/+) (n = 12), Baff^wt/E247K (ki/+) (n = 20), and Baff^E247K/E247K (ki/ki) (n = 16) littermates and in the serum of Baff^−/− (−/−) (n = 12) mice. Mean ± SEM. One-way Anova followed by Bonferroni comparing +/+ to other genotypes. NS = not significant: p > 0.05; ***p < 0.001. The experiment was performed twice. b Same as panel a, except that BAFF was measured with one soluble receptor (TACI-Fc) and one anti-mouse BAFF antibody (Sandy-2). The experiment was performed once. c Flow cytometry analysis of lymphocytes with T cell (CD19⁻, CD93⁻), mature B cell (matB) (CD19⁺, CD93^low), and immature B cell (imB) (CD19⁺, CD93⁺) phenotypes in spleens of mice of the indicated genotypes. Percentages of cells in each quadrant are indicated. d Same as panel c, but for T (CD3⁺) and B (CD19⁺) lymphocytes in lymph nodes. e Number of B cells in spleens of 7 mice per group (8 mice for WT) of the indicated genotypes from two pooled experiments differentiated by black and gray circles. Mean ± SEM. One-way Anova followed by Bonferroni comparing +/+ to other genotypes. ***p < 0.001. f Same as panel e, but showing B to T cell ratio in lymph nodes. g Number of mature B cells in spleens of mice (4 mice per group, 3 for WT, 5 for +/−) of the indicated genotypes, all littermates. Mean ± SEM. One-way Anova followed by Bonferroni comparing +/+ to other genotypes. ***p < 0.001. The experiment was performed once in this format (and twice comparing +/+, +/−, and −/−). h Same as panel g, but showing B to T cell ratio in lymph nodes. See also Supplementary Figs. 2, 3, and 4, and Supplementary Tables 1 and 2