CD40 Ligand (CD40-L, CD40 ligand, Tumor necrosis factor ligand superfamily member 5, TNF related activation protein, T cell antigen Gp39, CD154 antigen)

CD40 belongs to the TNF receptor superfamily. A key role of CD40/CD40ligand interactions in immune activation, particularly in T-cell dependent B cell responses is anticipated. This molecule as well as the other ligands of the family share the property of co-stimulation of T-cell proliferation and are all expressed by activated T-cells.Because the ligand of CD40 (CD40L) is expressed on activated T helper cells, B cells may escape from apoptosis and are activated when the immune system interacts with foreign antigens, which are normally able to activate T-helper cells. Thus the CD40/CD40L interaction plays a central role in the various phases of the B cell response to T-dependent antigens.