Mature B cell phenotypes in Sh2b3 ^Δ , Sh2b3 ^E372K , and Sh2b3 ^R530Q mice, and chimeras of Sh2b3 ^E372K mice. (A) Frequencies of mature B cells as percentages of splenic B cells. (B) Total numbers of splenic mature B cells. (C) Frequencies of FO B cells as percentages of splenic B cells. (D) Total splenic FO B cells. (E and F) Total splenic MZ B cells (E) and CD21⁻CD23⁻ mature B cells (F). Each dot represents one mouse. Sample numbers for each group in A–F are listed as follows: Sh2b3^Δ panels: +/+ (n = 5), Δ/+ (n = 7), Δ/Δ (n = 6); Sh2b3^E372K panels: +/+ (n = 4), E372K/+ (n = 3), E372K/E372K (n = 4); Sh2b3^R530Q panels: +/+ (n = 5–11), R530Q/+ (n = 6–7), R530Q/R530Q (n = 6–9). Means are shown as bars. One-way ANOVA was used for statistical analysis. (G–J) CD45.2⁺/CD45.1⁺ ratios of frequencies of splenic mature B cells (G), MZ B cells (H), FO B cells (I), and CD21/35⁻CD23⁻ mature B cells (J) in 50:50 BM chimeras of CD45.1-Sh2b3^+/+ and CD45.2-Sh2b3^+/+ (n = 10) or Sh2b3^E372K/E372K (n = 10) mice. Statistical analysis was performed using Student’s t test. Results are representative of two independent experiments. (K) Representative flow cytometric plot of splenic ABCs (B220⁺CD21/35⁻CD23⁻CD11c⁺CD19⁺). (L and M) Frequencies (L) and total numbers (M) of splenic ABCs. Each dot represents one mouse. Sample numbers for each group in L and M are listed as follows: Sh2b3^E372K panels: +/+ (n = 4), E372K/+ (n = 5), E372K/E372K (n = 4); Sh2b3^R530Q panels: +/+ (n = 5–11), R530Q/+ (n = 7), R530Q/R530Q (n = 6). Results are representative of two to three independent experiments. Means are shown as bars. One-way ANOVA was used for statistical analysis of immunophenotyping data (A–F, L, and M), while Student’s t test was used for analyzing data from BM chimera experiments (G–J). Significance levels of one-way ANOVAs are indicated with asterisks, while those of Student’s t tests are indicated with hashes. Significance level criteria are indicated as follows: *: P < 0.05, **: P < 0.01, ***: P < 0.001, ####: P < 0.0001.