GITR Ligand, also known as TNFSF18 and TL6, is an approximately 30 kDa type II transmembrane glycoprotein in the TNF superfamily (1). Human GITR Ligand consists of a 50 amino acid cytoplasmic domain, a 21 aa transsmembrane segment, and a 128 aa extracellular domain (ECD). Within the ECD, human GITR Ligand shares 56% and 60% aa sequence identity with mouse and rat GITR Ligand, respectively. TNFSF18 is expressed at high levels in the small intestine, ovary, testis, kidney and endothelial cells. GITRL/TNFSF18 is up-regulated after stimulation by bacterial lipopolysaccharides (LPS). TNFSF18 Can function as costimulator and lower the threshold for T-cell activation and T-cell proliferation. TNFSF18 / GITR Ligand is important for interactions between activated T-lymphocytes and endothelial cells.Recombinant Human GITR Ligand Fc Chimera produced in HEK293 cells is a polypeptide chain containing 359 amino acids with the C-termimal human IgG1 Fc fragment. A fully biologically active molecule, rhGITRL has a molecular mass of 50 kDa analyzed by reducing SDS-PAGE and is obtained by chromatographic techniques at GenScript.