FIGURE 1.

Inactivation of Elk4 and Elk1 increases numbers of thymic innate-like αβ CD8⁺ T cells. (A) Top panels, TCRβ staining in thymocytes isolated from 8-to-12-wk-old WT, Elk4^−/−, and Elk4^−/−Elk-1^−/− female animals, with proportions of CD4 and CD8 in TCRβ^hi-gated thymocytes below. Lower panels, TCRβ^hi CD8⁺-gated thymocytes were stained for cell surface expression of CD44, CD122, CXCR3, HSA, and intracellular Eomes. Gated percentages are indicated. (B) Proportions (left) and absolute cell numbers (right) of TCRβ^hi CD8⁺ CD122⁺ innate T cells in WT, Elk4^−/−, and Elk4^−/− Elk1^−/− thymus. Data are representative of three independent staining experiments with ≥5 animals per genotype. (C) Levels of Eomes mRNA transcripts in WT and Elk4^−/−Elk1^−/− purified CD8⁺ SP thymocytes, three animals per genotype. Data are representative of three independent experiments. (D) TCRβ^hi CD8⁺-gated WT and Elk4^−/− Elk1^−/− thymocytes were stained for cell surface expression of NKG2D, intracellular CCL5, and T-bet. Proportions of TCRβ^hi CD8⁺ CD44⁺ NKG2D⁺, CCL5⁺, or T-bet⁺ cells are shown. n = 5 animals for each genotype; error bars represent SEM. Statistical significance: **p < 0.01, ***p < 0.001, ****p < 0.0001 (unpaired t test).