The Mechanism of Anti-PD-L1 Antibody Efficacy against PD-L1-Negative Tumors Identifies NK Cells Expressing PD-L1 as a Cytolytic Effector

Targeting PD-L1 expressed on PD-L1+ tumors with anti-PD-L1 mAb successfully overcomes T-cell exhaustion to control cancer, yet patients with PD-L1 - tumors can respond to anti-PD-L1 mAb. Here, we show that anti-PD-L1 mAb activates PD-L1+ NK cells to control growth of PD-L1 - tumors in vivo, and does so independent of PD-1.This article is highlighted in the In This Issue feature, p. 1325.