Elevated IFN-γ levels lead to AICD. (A) B6 mice were lethally irradiated and infused with 10⁷ BALB/c NTCD BM and 3 × 10⁶ BALB/c or Tim-3^−/−–purified CD25⁻ T cells. Mice were killed on day 7, and splenocytes were analyzed for IFN-γ (n = 4), granzyme-B (n = 8), and Ki-67 (n = 8; *P < .05, ***P < .001). (B) B6 mice were lethally irradiated and infused with 10⁷ BALB/c NTCD BM and 3 × 10⁶ BALB/c or Tim-3^−/−–purified CD25⁻ T cells. Mice were killed on day 7, and splenocytes were analyzed for Annexin V/7-AAD (n = 4) and activated caspase-3 (P < .05, n = 8). (C) B6D2F1 mice were lethally irradiated and infused with 10⁷ B6 NTCD BM, 5 × 10⁵ B6-purified T cells, and 2.5 × 10⁴ TEa monoclonal luciferase–enriched T cells.