Figure S3.

The inhibition of the generation of IgE-producing B cells by IL-21 in vitro is independent of cell division. Related to Fig. 6. Purified mouse B cells, labeled with CellTrace Violet, were cultured for 4 d with anti-CD40 (62.5 ng/ml) and IL-4 (12.5 ng/ml), with the addition of IL-21 (50 ng/ml) to the indicated samples on day 1. (A) Representative flow cytometry of cell divisions shown by dilution of CellTrace Violet dye. Cells that had undergone three to six divisions were gated for further analysis. (B) Representative flow cytometry showing B cell activation and CSR (IgD⁻, left) and PC differentiation (CD138⁺, right) in relation to CellTrace Violet dilution. (C and D) Quantification of the frequency (C) and number (D) of IgE⁺ and IgG1⁺ cells among IgD⁻IgM⁻ cells in different cell divisions. Cells were from WT mice on a B6 background bred in our colony. Dots represent data points from individual mice (C and D). Bars represent the mean (C) or the geometric mean (D). n.s. not significant; **, P < 0.01; ***, P < 0.001; ****, P < 0.0001 (t tests with the Holm-Sidak correction for multiple comparisons [C and D]). Data in C and D awere pooled from four experiments.