IL-4R and BAFF-R signaling in the survival in IgM-crosslinked splenic B cells of Sh2b3 ^+/+ , Sh2b3 ^E372K/+ , and Sh2b3 ^E372K/E372K mice. (A) Representative flow cytometry plot showing the gating strategy of apoptotic (Annexin⁺7-AAD^−/+) cultured, sorted splenic B cells. (B and C) Frequencies of apoptotic transitional (B) and mature B cells (C) in untreated, 20 ng/ml IL-4 only, 5 μg/ml anti-IgM (α-IgM) only, and 5 μg/ml α-IgM + 20 ng/ml IL-4 conditions (n = 3 in each group). Two-way ANOVA with Šídák’s adjustment was used for statistical analyses; *: P < 0.05. (D and E) BAFF-R expression was measured by GMFI in transitional (D) and mature (E) B cells in untreated or 20 ng/ml IL-4 conditions (n = 4 in each group). Two-way ANOVA with Šídák’s adjustment was used for statistical analyses. *: P < 0.05, **: P < 0.01, ***: P < 0.001, ****: P < 0.0001. Results are representative of three independent experiments. (F) Plasma IL-4 measured by Meso Scale Discovery assay (+/+: n = 3, E372K/+: n = 5, E372K/E372K: n = 3). One-way ANOVA was used for statistical analyses. Results are from a single experiment. (G) Serum BAFF measured by bead-based immunoassay (+/+: n = 7, E372/+: n = 11, E372K/E372K: n = 12). Results are pooled from two independent experiments. One-way ANOVA was used for statistical analyses.