GL7− Breg cells derive from CD21hi MZP B cells. (A, B) Splenic CD21−/lo, CD21hiCD23+ (marginal zone precursor, MZP B cells) and CD21hiCD23− (marginal zone, MZ B cells) B cells from .from wild-type (A–C) or CD19-deficient mice (C) were stimulated for 3 days with LPS (1 μg/ml) and analyzed by the intracellular cytokine-staining assay. Quadrants indicate percentage of IL-10-expressing GL7− and GL7+ B cells (A, C). Statistical analysis of the percentages of GL7−IL-10+B and GL7+IL-10+B cells in CD21−/lo, CD21hiCD23+ and CD21hiCD23− B cells (B). Data represent 3 independent experiments. (B) Data were analyzed by Student’s t-test (two tailed). Error bars, s.e.m. *P < 0.05, ****P < 0.0001.