Fig. 2: In two AML models, the frequency, cytokine output, and immunosuppressive activity of activated ST2⁺ T_reg cells in malignant leukemic niches—bone marrow, spleen, and liver—intensify progressively over time.

A Kinetics of KLRG1⁺ST2⁺ T_reg cells in the malignant BM, spleen, and liver niches post leukemic cell challenge (10⁵ per mouse). Frequencies of KLRG1⁺ST2⁺ T_reg cells in the malignant BM niches on the indicated days post MLL-AF9 leukemic cell challenge (n = 4 on days 0, 5 and 10, and n = 10 on day >20), or post DNMT3A/FLT3^ITD-mutant leukemic cell challenge (n = 4 on days 0 and 5, n = 5 on day 10, and n = 10 on day >20). B Representative flow plots and frequencies of TGFβ⁺ST2⁺ T_reg cells (n = 4) and IL-10⁺ST2⁺ T_reg cells (n = 5) in the malignant BM niches on day 10 post MLL-AF9 leukemic cell challenge or (10⁵ per mouse). C Representative flow plots and frequencies of TGFβ⁺ST2⁺ T_reg cells (n = 6) and IL-10⁺ST2⁺ T_reg cells (n = 5) in the malignant BM niches on day 10 post DNMT3A/FLT3^ITD leukemic cell challenge or (10⁵ per mouse). D Percentages of T_reg cells positive for cytokines (TGFβ, IL-10) and functional markers (LAG3, TIM3, and GITR) among paired ST2⁺ T_reg cells versus ST2⁻ T_reg cells on day 10 post MLL-AF9 cell challenge (10⁵ per mouse, n = 5). Data are from two different replicates (shown as different shapes). The control group had no tumor cell transfer. A paired t-test was used to compare ST2⁺ T_reg cells versus ST2⁻ T_reg cells. E Immunosuppression assay of ST2⁺ T_reg cells versus ST2⁻ T_reg cells. Percent suppression of ex vivo T cell proliferation at various ratios of T_reg: CD8 T (1:1, 1:3, 1:6, 1:12) for cells taken on day 10 post MLL-AF9 leukemic cell challenge and cultured for 5 days (n = 2). The data are presented as means ± s.e.m. (error bar), and compared using two-sided unpaired t-test or ANOVA with post-hoc Bonferroni t-test for three groups or more. P values are presented in the figure. Source data are provided as a file.