Phenotype, regulatory function, and TCR repertoire of Vα2⁺ and Vα12⁺ PBMCs. (A) CD4/CD8 ratio and expression of (B) CD25 and (C) CD45RO within the CD4⁺ subset. (D) Expression of FOXP3 mRNA and protein (TCR αβ⁺: ▦;Vα2⁺: □;Vα12⁺: ▪). (E) Suppression of T-cell proliferation and IFN-γ production by CD25^hi cells expressing Vα2, Vα12, or both, with total CD25^hi cells as a control (nonstimulated PBMCs: □; anti-CD3–stimulated PBMCs: ▪; anti-CD3–stimulated PBMCs cocultured at a ratio of 1:1 with the indicated CD25^hi subsets: ▦). The cell numbers in the cultures were adjusted to the number of CD25^hi Vα2⁺Vα12⁺ cells obtained (3000 to 4000). (F) TCR Vα2 and Vα12 repertoire in CD4⁺ cells. (G) Part of the TCR β repertoire in isolated Vα2⁺ and Vα12⁺ cells. The results in panels D and E are the mean and, in other panels, a representative example of 2 to 4 independent experiments.