Abnormal early T-cell compartment in leukemic AKR/J mice. (A) Thymus from leukemic (6 months) and young (2 months) AKR/J mice were characterized by FACS analysis in comparison to control B10.BR thymocytes. Numbers shown in FACS profiles denote percentages of cells in each quadrant. Thymocytes were analyzed with 3-color staining by using anti-CD4–PE, anti-CD8–FITC, and anti-TCRαβ–-Cy (i-ii). FACS profiles (i) show analysis of CD4 versus CD8 distribution in total thymocytes. Histograms profiles (ii) show level expression of TCRαβ among gated DN (solid line) versus DP (thin dashed line) and CD4⁺ SP (thick dashed line) thymocytes. CD44 versus CD25 distribution (iii) was analyzed among gated DN thymocytes by 4-color staining using anti-CD4–PE, anti-CD8–FITC, anti-CD25–APC, and anti-CD44–Cy antibodies. (B) Thymus isolated from leukemic (6 months) and young (2 months) AKR/J mice were examined by hematoxylin and eosin staining. Dark areas represent thymic cortex, whereas light areas show thymic medulla. Results (A-B) are representative of 3 independent experiments with n = 3 mice for each experiment. Original magnification × 40.