Leukemia involves the accumulation of ISP CD8+T-cells and blockages in B-cell development. Leukemia involves the accumulation of ISP CD8+T-cells and blockages in B-cell development. (A) Thymic T-cell distribution based on CD4 and CD8 expression. (B) CD8+ cells are separated according to CD24 and surface TCRβ expression. (C) Summary of T-cell development data, shown as a percent of total thymus cells, for WT (n=6), R26PR;Mx1-cre+pIpC (n=6) and R26PR;MMTV-cre (n=8). (D) Total number of splenic B220+ B-cells. FSC, forward scatter. (E) B220+ gated cells are separated according to CD19 and CD43 expression. Cells are blocked at the early-pro-B stage in R26PR;cre animals and had reduced progression to the pro-B stage compared with controls. (F) CD19+CD43− gated cells are separated according to surface IgM expression for pre-B and mature B-cell discrimination. (G) Summary of B-cell development data, shown as a percent of total spleen cells, for WT (n=4), R26PR;Mx1-cre+pIpC (n=6) and R26PR;MMTV-cre (n=8). Groups were compared using one-way ANOVA with Dunnett’s test for multiple comparisons. ***P<0.001. Representative flow plots show averages of R26PR;Mx1-cre and R26PR;MMTV-cre values in each panel. Brandi L. Carofino et al. Dis. Model. Mech. 2013;6:1494-1506 © 2013. Published by The Company of Biologists Ltd