PD-L1/PDCD1-L1/CD274 [MD21R]

Programmed cell death 1 ligand 1 (PD-L1) also known as CD274 or B7-H1, a member of the B7 family of cell surface ligands, involved in regulation of T cell activation and humoral immune responses. The PD-L1 binds its transmember receptor PD-1 and provides both stimulatory and inhibitory signals in regulating T cell activation and tolerance during pregnancy, tissue allografts, autoimmune disease and malignant transformation. PD-L1 is expressed in activated T and B cells, placenta and some tumors including melanoma, diffused large B-cell lymphoma, lung, ovary, colon, breast, rectum and renal cell carcinomas. Expression of PD-L1 in cancer is associated with tumor infiltrating lymphocytes, which mediate PD-L1 expression through the release of interferon gamma. Additional research links PD-L1 expression to cancers associated with viral infections.