IFN-γ is required for the induction of optimal GVL effects.

B6 mice were irradiated and transplanted with 5 × 10⁶ B6 TCD BMC (▪, syngeneic), or 5 × 10⁶ TCD BMC and 7.5 × 10⁶ CD4-depleted splenocytes from WT (○,WT BALB) or GKO (●, GKO BALB) BALB/c donors. Leukemic recipients were additionally injected with 500 EL4 cells along with the BMT inoculum. Survivals of nonleukemic (A) and leukemic (B) recipients are shown.