Programmed death-ligand 1 and programmed cell death protein 1 (PD-L1 and PD-1)

The Programmed death-ligand 1/programmed cell death protein 1 pathway is an immune checkpoint system wherein PD-L1, encoded by the CD274 gene and widely expressed on tumor and immune cells, binds to the PD-1 receptor (encoded by PDCD1) on T cells. This interaction transmits an inhibitory signal that downregulates T-cell activation, leading to immune tolerance and suppression of antitumor immunity. Tumors frequently exploit this pathway to evade immune destruction. Blockade of PD-1/PD-L1 interaction using monoclonal antibodies has revolutionized cancer immunotherapy, enabling durable responses in multiple cancer types, though it is accompanied by risk of immune-related adverse effects.

Other names

CD279programmed cell death protein 1PDCD1CD274B7 homolog 1 (B7-H1)PD-1/PD-L1 axisPD-1/PD-L1 immune checkpointPD-1/PD-L1 signaling pathway

Inhibition of PD-1/PD-L1 binding restores T-cell activation and antitumor immune responses by blocking the checkpoint-mediated immunosuppression