Inefficient rescue of B cell development upon in vivo tamoxifen treatment of E2AER/ER mice. (A) Two month old E2AER/+ and E2AER/ER control mice were treated with tamoxifen in their drinking water for 27 days. Indicated tissues were stained as shown. All plots are pre-gated on 7AAD- lymphocytes. Histograms are pre-gated on B220+CD43+ cells as shown. Relative percentages are displayed. (B) Representative spleen staining from age-matched non-treated E2AER/+ and E2AER/ER mice.