A bcl-x_L (bcl⁺) transgene rescued CD8αα, αβ-TCR IELs in bi-5 mice, but not γδ-IELs or NK T cells.

(A) IL-2Rβ and γ_c expression in bcl⁺/bi5⁺ mice. IL-2Rβ was reduced in bi-5⁺/bcl⁺ pro-T thymocytes, but γ_c was expressed at normal levels. (B) NK T cells and (C) γδ-IELs were not rescued by bcl-xl in bi-5⁺ mice. (D) CD8α versus CD8β on αβ⁻TCR⁺IELs. Bcl-x_L appeared to restore the number of CD8αα αβTCR⁺ IELs in the bi-5 mice. The ratio of CD8αα to CD8αβ IELs was similar for both bcl⁺/bi-5⁺and bcl⁺/bi-5⁻ mice. Two plots of bcl⁺/bi-5⁺ are shown to demonstrate the degree of variability. There was also a substantial increase in the numbers of α,β TCR⁺CD8⁻ T cells in bcl-x_Ltransgenic mice. These could be either CD4⁺ T cells or coreceptor–negative T cells.