4–1BBL, a member of the TNF superfamily, is expressed in B cells, dendritic cells, activated T cells and macrophages. 4–1BBL binds to its receptor 4–1BB and provides a co-stimulatory signal for T cell activation and expansion. The human 4–1BBL gene codes for a 254 amino acid type II transmembrane containing a 28 amino acid cytoplasmic domain, a 21 amino acid transmembrane domain and a 205 amino acid extracellular domain. The soluble form of 4–1BBL contains the TNF-like portion of the extracellular domain of 4–1BBL. Recombinant human 4–1BBL is a soluble 19.5 kDa protein consisting of 185 amino acid residues.
Amino Acid Sequence
Determined by the dose-dependent stimulation of IL-8 production by human PBMC. The ED50 for this effect is 5–10 ng/ml. Note: Results may vary with PBMC donors.
Endotoxin level is <0.1 ng/μg of protein (<1EU/μg).
Centrifuge the vial prior to opening. Reconstitute in water to a concentration of 0.1–1.0 mg/ml. Do not vortex. For extended storage, it is recommended to further dilute in a buffer containing a carrier protein (example 0.1% BSA) and store in working aliquots at –20°C to –80°C