Figure 6.

Changes in the proportions of apoptotic (a) and cycling thymocytes (b) of mutant mice compared with control WT values. (a) Annexin-V staining in combination with CD4/CD8 cell marker expression was used to determine the percentage of apoptotic cells within the different thymic subpopulations. Dead cells were excluded by using propidium iodide (PI) staining. The percentage of apoptotic cells (mean ± SD) increased significantly in total thymocytes (total) as well as in both DN and DP cells, but not in the SP cell subpopulations of mutant mice. (b) Cell cycle in both WT and mutant mice was analyzed by combination of Hoechst 33342 and CD4/CD8 cell marker expression. The percentage (mean ± SD) of cells in S+G₂+M phases is represented. Note the decreased proportion of cycling cells that occurs in the DN (CD4⁻ CD8⁻) cell compartment but not in the other thymocyte subsets of mutant thymuses.