LAG-3 Protein, Human (Biotinylated, HEK293, mFc-Avi)

LAG-3 (Lymphocyte activation gene 3) protein, an inhibitory receptor present on antigen-activated T-cells, plays a crucial role in immune regulation. Upon binding to its major ligand, FGL1, LAG-3 delivers inhibitory signals that negatively regulate the proliferation, activation, effector function, and homeostasis of both CD8(+) and CD4(+) T-cells. Acting in synergy with PDCD1/PD-1, LAG-3 may inhibit antigen-specific T-cell activation, particularly following T-cell receptor (TCR) engagement where it associates with CD3-TCR in the immunological synapse. Beyond its role in T-cell inhibition, LAG-3 is constitutively expressed on a subset of regulatory T-cells (Tregs), contributing to their suppressive function and mediating immune tolerance. Additionally, LAG-3 negatively regulates plasmacytoid dendritic cell (pDCs) activation and, intriguingly, interacts with MHC class II (MHC-II), potentially acting as both a ligand for MHC-II on antigen-presenting cells (APC) and a promoter of APC activation/maturation, thereby influencing Th1 immune response.