Programmed cell death 1 ligand 1 (PD-L1) - Programmed cell death protein 1 (PD-1) interaction interface (PD-L1/PD-1 interface)

The Programmed cell death 1 ligand 1 (PD-L1) - Programmed cell death protein 1 (PD-1) interaction interface is a critical immune checkpoint pathway that regulates the balance between immune activation and tolerance (Pardoll, 2012). PD-1 is an inhibitory receptor expressed on the surface of activated T-cells, while its ligand, PD-L1, is often upregulated on tumor cells to evade immune detection (Han et al., 2020). When these two proteins bind at their interface, they trigger a signaling cascade that inhibits T-cell proliferation and cytokine production, leading to T-cell exhaustion (Sharpe & Pauken, 2018). This interaction serves as a major mechanism of immune escape for various cancers, allowing tumors to grow unchecked by the host's immune system (Chen & Han, 2015). Therapeutic agents, primarily monoclonal antibodies, are designed to bind specifically to this interface or the individual proteins to block the interaction (Gong et al., 2018). By preventing PD-L1 from binding to PD-1, these drugs effectively release the brakes on the immune system, reactivating T-cells to recognize and destroy cancer cells. This target has become a cornerstone of modern oncology, with multiple approved drugs for indications such as melanoma, lung cancer, and renal cell carcinoma. Despite its success, targeting this interface can lead to immune-related adverse events where the immune system attacks healthy tissues, necessitating careful patient monitoring (Postow et al., 2018).

Other names

PD-1/PD-L1 axisPD-1/PD-L1 pathwayCD274/PDCD1 interactionImmune checkpoint PD-1/PD-L1

Competitive inhibition of the binding between PD-1 and PD-L1 to prevent inhibitory signaling in T-cells and restore anti-tumor immunity.