Recombinant Human PD-L1/B7-H1/CD274 Protein (C-His)

Measured by functional ELISA. Immobilized recombinant human PD-L1 binds recombinant human PD-1 with an EC50 in the range of 30–80 ng/mL, and the interaction is efficiently blocked by reference anti-PD-L1 antibodies.

PD-L1 (programmed death-ligand 1), also known as B7-H1 and CD274, is the primary ligand of the PD-1 immune checkpoint receptor. A type I transmembrane member of the B7 family, PD-L1 contains one IgV- and one IgC-like extracellular domain and is expressed on antigen-presenting cells under resting conditions and broadly upregulated on tumor cells, stromal cells and inflamed tissues in response to interferon-γ. Engagement of PD-1 by PD-L1 transmits inhibitory signals that dampen T cell proliferation, cytokine production and cytotoxicity — a pathway that tumors hijack to establish an immunosuppressive microenvironment. PD-L1 expression assessed by IHC remains the most widely used companion diagnostic for PD-1/PD-L1 checkpoint blockade. Recombinant human PD-L1 is widely used in ligand–receptor binding and blocking assays for inhibitor development, diagnostic antibody validation, and affinity characterization by SPR/BLI.