Purity ≥ 90% (SDS-PAGE). Endotoxin: ≤0.1EU/ug protein (LALmethod). OX40L is a membrane-expressed cytokine that belongs to the TNF ligand family. It acts as co-stimulator through interaction with its ligand OX40 on T cells, stimulating T cell activation, proliferation and cytokine production. OX40L is expressed on antigen presenting cells including B cells, dendritic cells, mast cells and endothelium. This hexameric protein is a high activity construct in which two trimeric OX40L ligands are artificially linked via the collagen domain of ACRP30 and therefore mimics the membrane-bound form of the protein. This construct very effectively activates T cell proliferation. Biological Activity: Activates T cell proliferation. Sequence: Each monomer in this construct consists of the extracellular domain of mouse OX40L (aa 52-199) fused at the N-terminus to mouse ACRP30headless (aa 18-111) and a FLAG?-tag.