Figure 2.

Combined Blockade of NKG2A and PD-1/PD-L1 Promotes Anti-tumor Immunity in A20 Tumor-Bearing BALB/c Mice

(A) Flow cytometry characterization of NK and CD8⁺ TILs 19 days after A20 tumor cells engraftment. The spleen was used as control. Upper panels: representative fluorescence-activated cell sorting (FACS) profiles of PD-1 and NKG2A expression on NK and CD8⁺ T cells in the spleen and the tumor bed. Lower panels: pie chart analysis (mean ± SD). The data presented are the pooled results of three independent experiments (n = 12).

(B) A20 tumor cells were engrafted in BALB/c mice. Tumor-bearing mice were then treated at 3- to 4-day intervals with an isotype control (IC), anti-NKG2A, anti-PD-L1, or a combination of these last two mAbs. Graphs show tumor growth in each individual mouse and combined survival curves. The data presented are the pooled results of three independent experiments. Complete regression are indicated. log rank test, ^∗∗p = 0.0087; ^∗∗∗p = 0.0001; ^∗∗∗∗p < 0.0001.

(C) Experiment similar to that described in (B) but with treatment of the mice with an anti-asialo-GM1 pAbs or an anti-CD8α mAb 1 day before the initiation of immunotherapy with the combination of anti-NKG2A and anti-PD-L1 mAbs. Graphs show tumor growth in each individual and combined survival curves. Complete regression are indicated. log rank test, ^∗p < 0.0016; ^∗∗p < 0.01; ^∗∗∗p = 0.0001.

See also Figure S2.