TCR α expression in thymocytes. (A) FOXP3 mRNA levels in CD4⁺CD8⁺ (DP: ▪), CD4⁺CD8^–CD25^– (CD25^–: □), and CD4⁺CD8^–CD25⁺ (CD25⁺: ▦) cells. (B) TCR Cα mRNA levels, normalized against β-actin and (C) against GAPDH expression. (D) Surface expression of αβ TCR and intracellular expression of TCR Vα12 chain in CD25^– (white profile) and CD25⁺ (gray profiles) cells. In panels A-C, the mRNA expression levels were determined by quantitative PCR and are shown on a relative scale as mean ± SD. *P < .05, **P < .005, ***P < .001; ns indicates not significant.