TNFRSF9, also known as tumor necrosis factor receptor superfamily member 9, interacts with TNFSF9 expressed on activated T cells and delivers a co-stimulatory signal for T cell activation and growth. It binds with high affinity to the transmembrane TNFSF9(4-1BB ligand) which expressed on antigen presenting cells and myeloid progenitor cells. Recombinant mouse TNFRSF9, fused to His-tag at C-terminus, was expressed in insect cell and purified by using conventional chromatography techniques.