Invitrogen™ 4-1BB Ligand Recombinant Rabbit Monoclonal Antibody (8E5D6)

CD137 ligand (CD137L) is a type II membrane protein and part of the TNF superfamily. CD137L is a co-stimulatory molecule that is expressed on antigen presenting cells (DCs, monocytes/macrophages, B cells) and is upregulated upon activation. Its receptor, CD137/4-1BB, is found on a variety of cells, including inflamed endothelial cells, where its expression enhances extravasation of CD137L expressing monocytes. Activated T cells also express CD137, and engagement with CD137L enhances T cell proliferation, IL-2 secretion, survival, and cytotoxic activity. CD137L is also expressed on a majority of B-cell lymphomas, including mantle cell lymphoma, follicular lymphoma, and diffuse large B-cell lymphoma (but it is lacking on Hodgkin lymphoma and T-cell lymphoma). CD137L is also expressed in carcinoma cell lines, and is thought to be involved in T cell-tumor cell interactions.