Use at an assay-dependent concentration. For Sandwich ELISA pairing: Human PD-L1 Antibody(Detector) (EPA1907D), with Human PD-L1 Protein (EPA1907S) as assay standards. The reference range value is 7.8-2,000 pg/mL.
Target info
Function
Programmed death-ligand 1 (PD-L1; CD274; B7-H1), encoded by the CD274 gene in human (chromosome 9p24.1), is a type I transmembrane B7-family immunoglobulin ligand and the principal ligand for the PD-1 checkpoint receptor. It is a 290-aa single-pass glycoprotein with an extracellular IgV-like domain followed by an IgC-like domain, a hydrophobic transmembrane helix and a short 30-aa cytoplasmic tail. PD-L1 is constitutively expressed on antigen-presenting cells (dendritic cells, macrophages, B cells), vascular endothelial cells, type II pneumocytes, placental syncytiotrophoblasts and some epithelial cells, and is strongly up-regulated by IFN-gamma through JAK-STAT1/IRF1 signaling in many tumors. On T cells engaged via TCR, PD-L1 binds PD-1 on the opposite cell, inducing ITSM phosphorylation on PD-1, recruitment of SHP-2 and dephosphorylation of CD3zeta/ZAP70/PKCtheta/PI3K-Akt intermediates, thereby attenuating T-cell proliferation, IL-2 and IFN-gamma production and cytotoxicity, and supporting peripheral tolerance. Tumor cells upregulate PD-L1 to engage PD-1 on tumor-infiltrating T cells and escape immune destruction; PD-L1 also binds CD80 (B7-1) in cis and can engage an unidentified activating receptor on IL-10-producing T cells. A soluble form (sPD-L1) is produced by alternative splicing and by ADAM10/ADAM17 shedding, and exosomal PD-L1 is immunosuppressive. PD-L1 is predominantly a plasma-membrane protein; intracellular pools reside in the Golgi, recycling endosomes and (in some tumors) cytoplasmic vesicles.
Subcellular Localization
Cell membrane, Early endosome membrane, Recycling endosome membrane, Nucleus.
