FIGURE 3.

Foxp3⁺ regulatory and conventional αβT cell development in competitive WT:Ccr4^−/− mixed bone marrow chimaeras. (A) A summary of the experimental strategy used to construct WT CD45.1/WT CD45.2 and WT CD45.1/Ccr4^−/− CD45.2 mixed bone marrow chimaeras. (B) The number of CD45.2⁺ WT (□) and CD45.2⁺Ccr4^−/− (▪) thymocytes recovered from such mice, taken together with representative flow cytometric analysis of thymocyte expression of CD45.2, CD4, and CD8. (C) Representative flow cytometric analysis of WT CD45.2⁺ (upper panels) and Ccr4^−/−CD45.2⁺ (lower panels) TCRβ^hi SP4 thymocytes for CD69/Qa2 and Foxp3 expression, along with CD25 expression by Foxp3⁻TCRβ^hi SP4 cells. (D) Absolute numbers of the indicated WT (□) and Ccr4^−/− (▪) SP4 thymocyte populations. (E) Confocal quantitation of the frequency of CD45.2⁺ WT (□) and CD45.2⁺Ccr4^−/− (▪) thymocytes within cortex (upper panel) and medulla (lower panel) regions of sections of chimaera thymuses. (B, D, and E) Error bars represent SEM. Data in (B)–(D) represents at least six mice per group in a minimum of two experiments; data in (E) represents three mice per group. An unpaired Student two-tailed t test was used: *p < 0.05, **p < 0.01.