Prolonged residence of immature-B cells in BM of S1P1 or S1P deficient mice.

<p>(A) Analysis of BrdU incorporation for 48 h in developing B cell subsets in chimeras reconstituted with mixtures of <i>Edg1^Fl/− Mb1^Cre/+</i> (gray bars, Ly5.2⁺) or <i>Edg1^+/+ Mb1^Cre/+</i> (white bars, Ly5.2⁺) with wild-type (Ly5.1⁺) BM. Shown is the ratio of percent BrdU⁺ Ly5.2⁺ and BrdU⁺ Ly5.1⁺ cells in the indicated developmental subsets. Data are pooled from 3 independent experiments. (B) BrdU incorporation for 48 h in developing B cell subsets from <i>Sphk-1</i> and <i>-2</i>-deficient (gray bars) and littermate controls (white bars). Data shown were pooled from 2 independent experiments. (C) BrdU incorporation for 48 h in developing B cell subsets from mice treated with saline (white bars) or FTY720 (1 mg/Kg; gray bars) for 3 days. Data shown are representative of 3 independent experiments. In all panels, bars indicate the mean, circles indicate individual mice. * P<0.05; ** P<0.005 (unpaired, two-tailed Student's <i>t</i>-test).