The T47-530 specifically recognizes the Lymphocyte Activation Gene 3 (LAG-3) protein which is also known as, Protein FDC, or CD223. LAG-3 is a ~70 kDa type I transmembrane glycoprotein that belongs to the Ig superfamily and exhibits homology to CD4. LAG-3 is expressed on NK cells, regulatory T cells, and activated conventional T cells with higher expression found on CD8+ T cells compared with CD4+ T cells. LAG-3 is an activation induced cell surface molecule that like CD4, binds MHC class II molecules, but with much higher affinity. This may enable LAG-3 to act as a negative competitor of CD4 for MHC class II ligand binding. LAG-3 may associate with the TCR-CD3 complex to downregulate TCR signal transduction and T cell clonal expansion. In contrast, LAG-3-induced signaling may promote dendritic cell activation.
The antibody was conjugated to BD Horizon BUV615 which is part of the BD Horizon Brilliant™ Ultraviolet family of dyes. This dye is a tandem fluorochrome with an Ex Max near 350 nm and an Em Max near 615 nm. BD Horizon Brilliant BUV615 can be excited by the ultraviolet laser (355 nm) and detected with a 610/20 filter and a 595 nm LP. Due to the excitation of the acceptor dye by the blue/yellow-green laser line, there may be significant spillover into channels detecting PE-CF594 like emissions (eg, 610/20-nm filter).