4-1BB Ligand (4-1BBL) (Carboxyfluorescein)

4-1BB Ligand (4-1BBL) is a type II transmembrane glycoprotein belonging to TNF superfamily (TNFSF) and has been designated TNFSF9. Mouse 4-1BBL cDNA encodes a 309 amino acid residues (aa) protein with an 82 aa N-terminal cytoplasmic domain, a 21 aa transmembrane domain and a 206 aa C-terminal extracellular domain. The extracellular domain of 4-1BBL has a tertiary structure similar to that other TNFSF members, but shares only low aa sequence homology (14-16%). Murine 4-1BBL shares 36% aa sequence identity with its human counterpart.1, 2 4-1BBL is predominantly expressed on activated antigen presenting cells (APCs) such as B cells, macrophages and dendritic cells (DCs). It is also expressed on most T and B lymphoma cell lines.3 A soluble 4-1BBL is released from the cell surface following cellular activation via proteolytic cleavage by one or more sheddases.4 By analogy to other TNFSF ligands, both the soluble and transmembrane 4-1BBL are expected to exist as non-covalent homotrimers. 4-1BBL binds 4-1BB, a TNF receptor superfamily member, TNFRSF9, which is also known as CD137 and ILA (induced by lymphocyte activation). 4-1BB is expressed on activated CD4+ and CD8+ T cells, thymocytes, and NK cells. It is also expressed on monocytes, neutrophils, DCs and eosinophils. In response to 4-1BBL binding, 4-1BB transduces a T cell costimulatory signal in both CD4+ and CD8+ T cells to promote survival and enhance proliferation, cytokine production and effector function. In dendritic cells, 4-1BB is a DC-activating molecules that enhances cytokine production and upregulates expression of B7-1 and B7-2 costimulatory molecules.3 Applications: Suitable for use in Flow Cytometry. Other applications not tested. Recommended Dilution: Flow Cytometry: use 10ul to label 10e6 cells. Optimal dilutions to be determined by the researcher. Storage and Stability: May be stored at 4 degrees C for short-term only. For long-term storage and to avoid repeated freezing and thawing, add sterile glycerol (40-50%), aliquot and store at -20 degrees C. Aliquots are stable for at least 6 months at -20 degrees C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.