CTLA-4 Blockade Bioassay
PD-1 is an immune inhibitory receptor expressed on activated T cells and B cells and plays a critical role in regulating immune responses to tumor antigens and autoantigens. Engagement of PD-1 by either of its ligands, PD-L1 or PD-L2, on an adjacent cell inhibits TCR signaling and TCR-mediated proliferation, transcriptional activation and cytokine production. Therapeutic antibodies and Fc fusion proteins designed to block the PD-1/PD-L1 interaction show promising results in clinical trials for the treatment of a variety of cancers. The PD-1/PD-L1 Blockade Bioassay is a biologically relevant MOA-based assay that can be used to measure the potency and stability of antibodies and other biologics designed to block the PD-1/PD-L1 interaction. The assay consists of two genetically engineered cell lines: PD-1 Effector Cells: Jurkat T cells stably expressing human PD-1 and NFAT-induced luciferase; PD-L1 aAPC/CHO-K1 Cells: CHO-K1 cells stably expressing human PD-L1 and a cell surface protein designed to activate cognate TCRs in an antigen-independent manner. When the two cell types are co-cultured, the PD-1/PD-L1 interaction inhibits TCR signaling and NFAT-mediated luciferase activity. Addition of an antibody that blocks either PD-1 or PD-L1 releases the inhibitory signal and results in TCR signaling and NFAT-mediated luciferase activity. Product Kit Formats and Related Products: Kits are available in 1X and 5X sizes. Control Ab, Anti-PD-1 is available separately. PD-L1 Negative Cells are available separately.