αβ and γδ innate T cells are not efficiently selected against functional TCR chains of the opposite isotype. (A) Expression of TCRVγ4 as determined by real time RT-PCR on mRNA derived from small bowel TCRβ⁺TCRγδ⁻ IELs sorted according to the expression of CD8α and CD8β. (B) Direct comparison of the expression of TCRVγ1 and TCRVγ4 mRNA in various T-cell subsets by real-time RT-PCR relative to β-actin. (C) Sorted NKT cells, T cells, and Tregs from WT and CD1d KO mice were retrovirally transduced with pMYδ27 and stained as indicated. Numbers in dot plots show percentages and indicate the purity of the sorted NKT cells (left panels) and percentages of TCRVγ4⁺TCRδ⁺ and TCRVγ4⁻TCRδ⁺ among GFP⁺ NKT cells, T cells, and Tregs (right panels). Data are representative of 2 independent experiments. (D) Percentages of intracellular (ic) TCRβ⁺ cells among TCRVδ6⁺ and TCRVδ6⁻ γδ thymocytes analyzed in individual WT mice as shown in the dot plots; data are representative of 3 independent experiments. P value of a paired t test is shown