Anti–PD-L1-blocking mAb restored endogenous T-cell function and prolonged surviving time of AML-bearing mice. B6 mice (10 mice/group) were injected with 10⁶ C1498FFDsR cells followed by anti–PD-L1 mAb (□) or rat IgG (■) treatment as described. In some studies, mice (3 or 4 mice /group) were killed 20 days after AML injection for the determination of proliferation by BrdU incorporation or 25 days after AML injection for determination of function by flow cytometric analysis. (A) Anti–PD-L1 mAb-treated mice had significantly prolonged survival compared with rat IgG control (□ vs ■, P = .029). (B) Anti–PD-L1 mAb treatment significantly increased the proliferation of CD8⁺ T cells in the liver of AML-bearing mice. (C) Anti–PD-L1 mAb treatment significantly increased the percentage of IFN-γ–secreting cells in the liver. (D) Anti–PD-L1 mAb treatment enhanced IFN-γ production by PD-1⁺ (left graph) but not PD-1⁻ (right graph) cells in the liver. Results from one of 3 representative experiments are shown. Bar graphs represent mean ± SD.