C3H.SW recipients were irradiated (10 Gy) on Day −1 and transplanted 5 × 106 syngeneic B6D2F1 BM (▾; n=16), allogeneic B6(WT) 5 × 106 TCD BM + B6(WT) 0.4 × 106 CD25-depleted T cells (●; n=21), B6(WT) 5 × 106 TCD BM + B6(WT) 0.4 × 106 CD25-depleted T cells + B6(WT) 0.2 × 106 CD4+CD25+ T cells (○; n=16), IL-10KO 5 × 106 TCD BM + B6(WT) 0.4 × 106 CD25-depleted T cells (■; n=21), or IL-10KO 5 × 106 TCD BM + B6(WT) 0.4 × 106 CD25-depleted T cells + B6(WT) 0.2 × 106 CD4+CD25+ T cells (□; n=13). Survival was monitored daily. Data from three similar experiments were combined and shown. ● versus ○, P = 0.0124; ■ versus □, P = 0.0001; ● versus ■, P = 0.1792; ○ versus □, P = 0.3703.