>95%, by SDS-PAGE visualized with Silver Staining and quantitative densitometry by Coomassie® Blue Staining.
<0.10 EU per 1 μg of the protein by the LAL method.
Measured by its binding ability in a functional ELISA. When Recombinant Human 4-1BB/TNFRSF9/CD137 is immobilized at 50 ng/mL, 100 μL/well, the concentration of
Human 4‑1BB Ligand/TNFSF9 (Catalog # 2295-4L)
that produces 50% of the optimal binding
response is approximately 2.5-12.5 ng/mL.
Chinese Hamster Ovary cell line, CHO-derived Leu24-His183, with a C-terminal 6-His tag
When Recombinant Human 4-1BB/TNFRSF9(Catalog # 9220-4B) is coated at 50 ng/mL, Recombinant Human4-1BB Ligand/TNFSF9 Recombinant Human 4‑1BB Ligand/ TNFSF9 (Catalog # 2295-4L) binds with a ED50 of 2.5-15 ng/mL.
4-1BB, also known as CD137 and TNFRSF9, is an approximately 30 kDa transmembrane glycoprotein in the TNF receptor superfamily. 4-1BB functions in the development and activation of multiple immune cells (1). Mature human 4-1BB consists of a 163 amino acid (aa) extracellular domain (ECD) with four TNFR cysteine-rich repeats, a 27 aa transmembrane segment, and a 42 aa cytoplasmic domain (2, 3). Within the ECD, human 4-1BB shares 60% aa sequence identity with mouse and rat 4-1BB. 4-1BB is expressed as a disulfide-linked homodimer on various populations of activated T cell including CD4+, CD8+, memory CD8+, NKT, and regulatory T cells (4-7) as well as on myeloid and mast cell progenitors, dendritic cells, mast cells, and bacterially infected osteoblasts (8-11). It binds with high affinity to the transmembrane 4-1BB Ligand/TNFSF9 which is expressed on antigen presenting cells and myeloid progenitor cells (3, 8). This interaction costimulates the proliferation, activation, and/or survival of the 4-1BB expressing cell (3-7). It can also enhance the activation-induced cell death of repetitively stimulated T cells (3). Mice lacking 4-1BB show augmented T cell activation, perhaps due to its absence on regulatory T cells (12). 4-1BB can associate with OX40 on activated T cells, forming a complex that responds to either ligand and inhibits Treg and CD8+ T cell proliferation (13). Reverse signaling through 4-1BB Ligand inhibits the development of dendritic cells, B cells, and osteoclasts (8, 11) but supports mature dendritic cell survival and costimulates the proliferation and activation of mast cells (9, 10). 4-1BB activation enhances CD8+ T cell and NK cell mediated anti-tumor immunity (14). It also contributes to the development of inflammation in high fat diet-induced metabolic syndrome (15). Soluble forms of 4-1BB and 4-1BB Ligand circulate at elevated levels in the serum of rheumatoid arthritis and hematologic cancer patients, respectively (16, 17).
Wang, C. et al. (2009) Immunol. Rev. 229:192.
Schwarz, H. et al. (1993) Gene 134:295.
Alderson, M.R. et al. (1994) Eur. J. Immunol. 24:2219.