OX40 ligand (OX40L, CD252) is part of the TNF receptor family and is expressed on activated T cells and antigen-presenting cells (APCs).
Its expression on APCs can be induced through CD40 signaling and is also seen in HTLV-I-infected human leukemic T cells. OX40L (CD134L) provides critical co-stimulation to CD4 T cells, enhancing their survival by inducing Bcl-xL and Bcl-2. Besides APCs, OX40L is found on NK cells, mast cells, smooth muscle, and vascular endothelial cells. OX40 ligation activates NF-κB pathways, promoting the expression of pro-survival molecules and increasing cytokine production. This leads to enhanced T-cell expansion, differentiation, and the formation of long-lived memory cells. OX40L plays a role in autoimmune diseases and cancer immunotherapy.

Abbreviations:

TXGP1L, TNFSG4, ATH-1, OX40L, GP34, OX-40L, OX40 LIGAND, TNLG2B, GP3, OX4, ATH1, Tumor necrosis factor ligand superfamily member 4.