OX40L
OX40 ligand
Protein family
OX40L is the ligand for OX40 (also known as CD134 or TNFRSF4) and is stably expressed on many antigen-presenting cells such as DC2s (a subtype of dendritic cells),[1] macrophages,[2] and activated B lymphocytes.[3]
The OX40 molecule, conversely, is present on the surface of activated T lymphocytes (mainly CD4+ T cells),[4] but also on NK cells,[5] NKT cells,[6] and neutrophils.[6] The ligation of OX40-OX40L is a source of survival signal for T cells[6] and enables the development of memory T cells.[7] Signaling through these two molecules also leads to polarization towards Th2 immune response even in an environment with low levels of IL-4 cytokine.[1][8]
OX40L is also present on the surface of many non-immune cells, for example, endothelial cells[9] and smooth muscle cells.[10]
The surface expression of OX40L is induced by many pro-inflammatory mediators, such as TNF-α, e.g. produced by mast cells,[11] IFN-γ[12] and PGE2 (prostaglandin E2).[13]
OX40L has also been designated CD252 (cluster of differentiation 252).[14]
Various single-nucleotide polymorphisms (SNPs) of the OX40L gene have been identified. For some of them association with systemic lupus erythematosus has been reported.[15] No association with occurrence of atherosclerosis has been found.[16]