OX40L

Class

anti-OX40L monoclonal antibody

Pathway

blocks OX40/OX40L co-stimulatory signaling that drives pathogenic T-cell activation; half-life extended (YTE Fc)

OX40L (CD252) is a protein belonging to the tumor necrosis factor superfamily, expressed mainly on antigen-presenting cells such as dendritic cells and activated B cells. It binds a receptor called OX40 (CD134) found on activated T lymphocytes, delivering a co-stimulatory signal that sustains T-cell activation, proliferation, and survival after antigen recognition. This OX40/OX40L axis amplifies immune responses and helps convert a short-lived T-cell response into durable, expanded T-cell populations, including memory T cells. In chronic inflammatory and autoimmune diseases, sustained OX40/OX40L signaling can contribute to pathogenic, self-perpetuating T-cell activity that drives tissue damage. Monoclonal antibodies that bind OX40L are designed to block this interaction at its source, preventing engagement of OX40 on T cells and thereby dampening the co-stimulatory signal without directly depleting T cells. This approach broadly matters in diseases characterized by chronic, T-cell-driven inflammation, such as atopic dermatitis, asthma, and other immune-mediated skin and respiratory conditions, where excessive T-cell persistence and activation contribute to ongoing tissue damage. Some anti-OX40L antibodies incorporate engineering changes that extend circulating half-life, allowing less frequent dosing while maintaining sustained blockade of this co-stimulatory pathway.