Figure 1. B cell–specific reduction of IRF5 expression in IRF5^ΔB mice.

All analyses were done in 8- to 10-week-old FcγRIIB^−/−Yaa mice. (A) Representative Western blot of IRF5 protein expression in sorted splenic B cells (CD19⁺) and myeloid cells (CD11b⁺Ly6G^–) from IRF5^F/+ and IRF5^ΔB mice. All lanes were run on the same gel but were noncontiguous. (B) Expression of IRF5 in B cells and myeloid cells from IRF5^ΔB mice normalized to IRF5^F/+ (n = 4). Data were analyzed using 2-tailed, unpaired Welch’s t test; **P < 0.01. (C) Representative flow cytometry plots of intracellular IRF5 expression in CD19⁺ B cells, CD11b⁺Ly6C⁺ monocytes, CD11b⁺Ly6G⁺ neutrophils, and CD11b^–PDCA1⁺Ly6C⁺ pDCs from IRF5^F/+, IRF5ΔB, and IRF5^–/– global knockout mice. (D) MFI values of IRF5 in B cells, monocytes, neutrophils, and pDCs from IRF5^F/+ and IRF5^ΔB mice (representative experiment of 3 individual experiments, n = 2 for each genotype). (E) IRF5 expression in B cells, monocytes, neutrophils, and pDCs from IRF5^ΔB mice normalized to the IRF5^F/+ littermate control in each experiment (n = 6). Data are shown as mean ± SEM and were analyzed using 1-way ANOVA with Tukey’s post hoc test; ****P < 0.0001. IRF5, IFN regulatory factor 5; pDCs, plasmacytoid DCs.