Phenotype o Rag2^-/- mice at the late phase of ICN1-induced leukemia. (A) CD4 compared with CD8 FACS analysis was performed at 11 weeks after reconstitution for the detection of EGFP⁺ (top panels), and EGFP⁺CD4⁺CD8⁺ cells (bottom panels) in peripheral blood (PB), bone marrow (BM), and spleen (SPL) of Rag2^-/- mice receiving syngeneic ICN1-transduced bone marrow. Rag2^-/- control mice that underwent reconstitution with Rag2^-/- bone marrow transduced with empty retrovirus and analyzed at the indicated time point do not contain EGFP⁺CD4⁺CD8⁺ cells in peripheral blood and organs (data not shown). (B) Macroscopic analysis and total yield of the spleen from the same animal described in panel A (top) and relative control mouse (bottom). Data are representative of at least 3 independent experiments.