IFN-γ inhibits GVHD while accelerating the destruction of recipient hematopoietic cells in sublethally irradiated allogeneic recipients. B6D2F1 mice received 6 Gy TBI one day before administration of 3 × 107 (A) or 2 × 107 (B,C) allogeneic splenocytes alone or along with 107 BMCs from WT or GKO B6 donors. Non-HCT controls were sublethally irradiated B6D2F1 mice receiving no transplantation. (A,B) Survival of non-HCT B6D2F1 controls and mice receiving WT or GKO B6 splenocytes alone (Spc) or splenocytes plus BMCs (Spc + BMC). *P < .05; **P < .01; ***P < .005. NS indicates not significant. (C) Levels of host-type (H-2d+) cells in WBCs prepared at day 50 from surviving mice in panel B. Each symbol represents an individual animal.