ST2–IL-33 signaling preserves central memory phenotype. (A) Representative plots of CD62L⁺ and CD44⁺ (left) and CD27⁺ and KLRG1⁺ (right) cells, and bar graphs showing the frequency of CD44⁺CD62L⁺, CD27⁺, and KLRG1⁺ CD8 T cells from in vitro differentiated cells from WT T9_IL-33 versus ST2^−/− T9_IL-33 cells (n = 4, from four independent experiments, unpaired t test; data are shown as mean ± SEM; **, P < 0.01). (B) Representative plots of CD62L⁺ and CD44⁺ (left) and CD27⁺ and KLRG1⁺ (right) cells, and bar graphs showing the frequency of CD44⁺CD62L⁺ and CD27⁺ CD8 T cells from ex vivo BM collected on day 28 from mice receiving MLL-AF9 leukemic cells with WT T9_IL-33 or ST2^−/− T9_IL-33 cells (n = 4, unpaired t test; data are shown as mean ± SEM; *, P < 0.05; **, P < 0.01). (C) Representative plots of Gzmb expression in WT or ST2^−/− CD8⁺KLRG-1⁺CD27⁻ short-term effector cells differentiated under T9_IL-33 conditions, and a bar graph showing the frequency of Gzmb expression in these cells (n = 3, unpaired t test; data are shown as mean ± SEM; ***, P < 0.001). (D and E) Representative plots of CD45RA⁻ and CCR7⁺ (D) and CD27⁺ and KLRG1⁺ (E) cells, and bar graphs showing the frequency of CD45RA⁻CCR7⁺, CD27⁺, and KLRG1⁺ CD8 T cells from in vitro differentiated T1, T9, and T9_IL-33 human cells (n = 3, from three independent experiments, paired t test; data are shown as mean ± SEM; *, P < 0.05; **, P < 0.01).