Biolegend, 561216, Biotinylated Recombinant Human CD223 (LAG-3)-Fc Chimera (carrier-free)

Initially documented in the 1990, lymphocyte activation gene 3 (LAG-3, CD223) is an inhibitory co-receptor of the type-1 immunoglobulin family with a molecular mass of 50 kD. LAG-3 exhibits four extracellular immunoglobulin-like domains named D1 to D4, a transmembrane region and an intracellular region. Except the proline-rich loop located on D1, LAG-3 is structurally similar to the CD4 co-receptor. LAG-3 selectively interacts with the major histocompatibility complex class II (MHC II) of antigen presenting cells (APCs) and tumor cells which activate the inhibitory pathway and eventually lead to dysfunction of T-cells. LAG-3 receptors and their ligands are expressed in the tumor microenvironment and form a complex organization for cell-communication. LAG-3 receptors are present on almost all T-lymphocytes (activated CD4+ T-cells, CD8+ T-cells, FOXP3+ regulatory T-cells and Naïve T-cells), NK cells and dendritic cells (DCs). Dendritic cells express both LAG-3 receptors and their ligands and LAG-3 induced signaling promotes their maturation. LAG-3 acts synergistically with PD-1 and/or other immunoregulatory genes to prevent autoimmunity in mice. The infiltrated LAG3+ lymphocytes are associated with overall survival of TNBC and HER2+ breast cancer patients, in addition, peripheral blood LAG3+ immunotype strongly corelates with treatment responses, survival, progression-free survival in melanoma. Current existing clinical therapeutic agents targeting LAG-3 can be classified into three different groups; the LAG-3 fusion protein, the LAG-3 monoclonal antibody and the LAG-3 involving bispecific antibody. A novel combinatorial FDA approved immunotherapy uses LAG-3 blocking agent together with nivolumab (anti-PD-1 agent) for metastatic melanoma’ which may suggest future prospects of LAG-3 targeted therapies for cancer patients.