FIG. 2.

Differentiation and proliferation defects in Mnt-deficient thymocytes. (A) Total thymocytes isolated from littermates (5 to 9 weeks old) with the indicated genotypes were enriched for DN T cells as described in the legend to Fig. 1B and analyzed for CD25 and CD44 expression by flow cytometry. The value in each quadrant represents the percentage of cells in one of the four DN populations (indicated in the lck-Cre half of the panel). Note the accumulation of thymocytes from lck-Cre-Mnt^flox/flox mice in the CD25⁺ CD44⁻ population (DN III). The results shown are representative of six independent experiments. (B) Representative flow cytometry profiles of thymocytes from lck-Cre-Mnt^flox/flox and littermate control mice stained with antibodies against CD4⁺ and CD8⁺. Values indicate the percentages of cells of the different T-cell subsets. (C) The absolute numbers of thymocytes representing the indicated developmental stages were calculated from FACS data and total cell numbers compiled from four independent experiments. Data are shown as means ± standard deviations (*, P = 0.03; **, P = 0.02; ***, P = 0.02). DN populations were not significantly different.