LAG-3/MHCII Blockade Bioassay
LAG-3 is an immune checkpoint receptor expressed on activated CD4+ and CD8+ T cells and natural killer (NK) cells, and plays a critical role in regulating immune responses to tumor antigens and autoantigens. Engagement of LAG-3 by its ligand, MHCII, on an adjacent cell inhibits TCR signaling, cytokine production and proliferation of activated T cells. Therapeutic antibodies designed to block the LAG-3/MHCII interaction show promising results in clinical trials for the treatment of a variety of cancers. The LAG-3/MHCII 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 LAG-3/MHCII interaction. The assay consists of two cell lines: LAG-3 Effector Cells: Jurkat T cells stably expressing human LAG-3 and a luciferase reporter driven by T-cell activation pathway-dependent response elements; MHCII APC Cells: APC Cells presenting TCR Activating Antigen (Ag), a proprietary peptide designed to specifically activate the TCR on the LAG-3 Effector Cells. When the two cell types are co-cultured in the presence of Ag, MHCII on the APC cells presents the Ag to the TCR on the LAG-3 Effector Cells to activate the Effector Cells. LAG-3 on the Effector Cells inhibits TCR signaling and promoter-mediated luciferase activity. Addition of the anti-LAG-3 antibody releases LAG-3 mediated inhibition, resulting in promoter-mediated luminescence. Product Kit Formats and Related Products: Kits are available in 1X and 5X sizes. Control Ab, anti-LAG-3 is available separately.