Induction of SHIP deficiency expands the CD25⁺FoxP3⁺ T_reg compartment in peripheral lymphoid organs. Spleen and mesenteric LN of polyI/C-treated MxCreSHIP^flox/flox (Cre⁺, n = 6) and SHIP^flox/flox (Cre⁻, n = 9) were harvested and processed into single-cell suspensions. Frequency and absolute numbers of CD4⁺CD25⁺FoxP3⁺ T_regs were assessed by flow cytometry, as described in Figure 1. (A) Representative CD4 versus CD25 staining in spleen and LN from MxCreSHIP^flox/flox and SHIP^flox/flox mice after poly(I/C) administration. (B) Percentage frequency of CD4⁺CD25⁺FoxP3⁺ T_regs after gating on CD3⁺ T cells, and total absolute CD3⁺CD4⁺CD25⁺FoxP3⁺ T_reg numbers in the spleen and LN of the indicated genotype. *P < .05. **P < .01. ***P < .001.