The FGL1:LAG3 Inhibitor Screening Assay is an AlphaLISA®-based assay designed to measure the inhibition of LAG3 binding to FGL1 in a homogeneous 384-reaction format. The assay is straightforward: first, FGL1 and LAG3 are incubated with or without a compound of interest. Then, acceptor and donor beads are added to the reaction, followed by reading the Alpha-counts.

Illustration of the assay principle.
FGL1 contains a His tag recognized by the Nickel chelate acceptor bead, whereas LAG3 is biotinylated, allowing its binding to the streptavidin-coated acceptor bead. Interaction between FGL1 and its receptor LAG3 brings the donor and acceptor beads in proximity. A singlet oxygen generated upon excitation of the donor bead leads to the excitation of the acceptor bead, which emits light. Light emission in the assay is proportional to the level of interaction. AlphaLISA™ immunoassays are a no-wash alternative to ELISA. These assays are robust, highly amenable to high throughput applications, and ideal for a minimal hands-on approach.