TNFSF4, Recombinant, Human (Tumor Necrosis Factor Ligand Superfamily Member 4, Glycoprotein Gp34, OX

OX40L, a member of the TNF superfamily of structurally related proteins, exists primarily as a type II membrane bound, non-covalently linked homotrimeric protein. It is expressed on antigen presenting cells (APCs), such as dendritic cells and activated B-cells, and also on various other cells such as vascular endothelial cells, mast cells, and natural killer cells. OX40L signals specifically through the OX40 receptor, which is expressed predominantly on CD4+T cells but also on certain activated CD8+T cells. OX40/OX40L functions as a costimulatory signal, which is required for a productive interaction between antigen presenting cells and their target T-cells. It enhances cell proliferation and survival, and increases expression of RANTES, IL-2, IL-3, and IFNgamma. OX40/OX40L signaling plays an important role in immuno-regulatory communication, enabling the immune system to distinguish between "friend vs. foe" during activation, a mechanism typically termed immuno-tolerance. Recombinant OX40L is a glycosylated 133aa protein corresponding to the extracellular TNF homologous domain of the full length transmembrane protein. It migrates with an apparent molecular mass of 15.5-25kD on SDS-PAGE. Source: Recombinant protein corresponding to human OX40 Ligand, expressed in Hi-5 Insect cells. Biological Activity: Determined by its ability to stimulate IL-8 production by human PBMC using a concentration range of 30-100ng/ml. Note: Results may vary with PBMC donors. Endotoxin: <0.1ng/ug (1EU/ug), Storage and Stability: May be stored at 4°C for short-term only. Aliquot to avoid repeated freezing and thawing. Store at -20°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.