Vit C–treated CD8⁺iTregs prevent GVHD while preserving GVL in the P815 mastocytoma model. (A-D) Lethally irradiated BDF1 mice were adoptively transferred with 2 × 10⁶ CD8⁺ iTregs, 5 × 10⁶ WT TCD-BM cells, and 5 × 10³ P815 mastocytoma cells. Three days later, 3 × 10⁶ CD25-depleted T cells were injected IV to induce GVHD. Recipient mice were monitored until day 80 for tumor burden (A), survival rate (B), tumor mortality (C), body weight (D), and clinical scores (E). Data are combined from 2 independent experiments (n = 9 or 10 per group). The log-rank (Mantel-Cox) test was used for statistical analyses of the survival and tumor-relapse data, and the Student t test was used for body weight loss and GVHD clinical score. *P ≤ .05, **P ≤ .01, ***P ≤ .001, ****P ≤ .0001.