Programmed cell death ligand 1 (PD-L1) also known as cluster of differentiation 274 (CD274) or B7 homolog 1 (B7-H1) is a type 1 transmembrane protein involved in the regulation of cellular and humoral immune responses. The interaction of PD-L1 with its receptor PD-1 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 on resting T cells, B cells, DCs, and macrophages and is further up-regulated upon activation. PD-L1 is also expressed on parenchymal cells, including vascular endothelial cells and pancreatic islet cells. The expression of PD-L1 has been discovered in a variety of epithelial cancers such as non-small cell lung carcinoma (NSCLC), pancreatic cancer, esophageal cancer, squamous cell carcinomas of the head and neck, andrenal cell carcinoma (RCC).
Programmed cell death ligand 1 (PD-L1) also known as cluster of differentiation 274 (CD274) or B7 homolog 1 (B7-H1) is a type 1 transmembrane protein involved in the regulation of cellular and humoral immune responses. The interaction of PD-L1 with its receptor PD-1 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 on resting T cells, B cells, DCs, and macrophages and is further up-regulated upon activation. PD-L1 is also expressed on parenchymal cells, including vascular endothelial cells and pancreatic islet cells. The expression of PD-L1 has been discovered in a variety of epithelial cancers such as non-small cell lung carcinoma (NSCLC), pancreatic cancer, esophageal cancer, squamous cell carcinomas of the head and neck, andrenal cell carcinoma (RCC).