FIGURE 3. Positive selection in T cell-specific RASA1-deficient AND TCR Tg mice.

All experiments were performed with thymi of littermate rasa1^fl/fl and rasa1^fl/fl plck-cre AND TCR Tg mice. (A) Representative flow cytometry plots of whole thymi showing gating method used to define successive stages of positive selection, A (CD4+CD8+), B (CD4dullCD8dull), C (CD4+CD8loCD69+) and D (CD4+CD8-CD69-). (B) At left is a representative flow cytometry plot showing expression of CD69 upon population A cells from rasa1^fl/fl (filled histogram) and rasa1^fl/fl plck-cre (open histogram) AND TCR Tg mice. The bar indicates CD69+ cells. At right is shown the mean percent + 1 SEM of CD69+ cells of population A (rasa1^fl/fl, n=11; rasa1^fl/fl plck-cre, n=10). (C) At left is shown the mean number + 1 SEM of populations A through D in thymi. Bar graphs at right show mean B/A and C/A ratios + 1 SEM (rasa1^fl/fl, n=11; rasa1^fl/fl plck-cre, n=10). (D) At top are representative histograms showing annexin V staining upon the indicated thymocyte populations from rasa1^fl/fl (filled histograms) and rasa1^fl/fl plck-cre (open histograms) AND TCR Tg mice. The bar indicates annexin+ cells. 7AAD+ cells were eliminated from analyses. At bottom is shown the mean percent + 1 SEM of annexin+ cells of each population (rasa1^fl/fl, n=4; rasa1^fl/fl plck-cre, n=4). Statistical significance was determined using the Student’s two-sample t-test.