The human GITRL extracellular domain is consisted of amino acids 72-199, with a mouse IgG2a FC tag linked at the C-terminus. Tumor necrosis factor ligand superfamily member 18 (TNFSF18) is a protein that belongs to the tumor necrosis factor (TNF) superfamily. It is also known as Glucocorticoid-induced TNF receptor ligand (GITRL). The protein is primarily expressed on antigen-presenting cells, such as dendritic cells, macrophages, and B cells, and it functions as a co-stimulatory molecule for the activation of T cells. TNFSF18-GITRL interaction is involved in the pathogenesis of autoimmune diseases, transplant rejection, and tumor immune evasion. Therefore, targeting TNFSF18 signaling is a promising therapeutic strategy for various diseases.