Figure 2. Presence of unusual CD5⁺ CD21^int CD23⁻ B cell subsets in lymph tissues of μs−/− mice.

(A) Shown are 5% contour plot with outliers of a representative spleen sample (n=4) from WT (left) and μs−/− mice (right) analyzed by flow cytometry after exclusion of dead cells. Boxes and arrows indicate gating strategy. Identified subsets among CD19+ B cells: CD21^hi CD23− marginal zone B cells (MZ), CD21^int CD23+ follicular B cells (FO), CD21^int CD23−,unknown B cell subset, and CD21− CD23− transitional/B-1 cells. CD21^int CD23− and CD21− CD23− subsets were gated on CD43 and CD5 to identify CD43+ CD5+ (B-1a), CD43− CD5+. (B) Bar graphs summarize the mean frequencies +/− SD and total numbers of different B cell subsets in spleen and lymph nodes of WT and μs−/− mice (n=4 per group). (C and D) Overlay histograms comparing CD21^int CD23− B cells from μs−/− and WT mice identifies CD21^int CD23− B cells as a unique cell subset not present in WT mice, as cells with that phenotype of WT mice are a mix of B-1 and immature B cells. Data are representative of three independent experiments.