FIGURE 7.

Peripheral αβ CD8⁺ memory-like T cells in Elk4-null animals do not arise through lymphopenia-induced proliferation. (A) Increased proportions and numbers of CD44⁺ CD122⁺ CD8 T cells in lymph nodes and spleen of primary animals. Levels of Eomes transcripts in purified CD8⁺ lymph node (LN) T cells. (B) Analysis of CD8⁺ T cells from Rag2^−/− hosts reconstituted with WT CD45.1 and Elk4^−/− CD45.2 bone marrow at 1:1 ratio. Increased proportions of CD44⁺ CD122⁺ CD8⁺ SP T cells in thymus (TH; WT, 0.53 ± 0.23%; Elk4 ^−/−, 1.34 ± 0.47%; 10 mice each), LN, and spleen (SP) (n ≥ 8 mice). Right, Increased expression of Eomes transcripts in Elk4 ^−/− sorted LN CD8⁺ cells. (C) Left, Representative flow cytometry plots of intracellular production of IFN-γ in LN CD8⁺ T cells from animals reconstituted as in (B) after stimulation with PDBu and ionomycin. Right, Data summary (n = 6). Data are expressed as mean ± SEM. Statistical significance: *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001 [unpaired (A) and paired (B and C) Student t test].