sCD40 Ligand (CD40L) ELISA

Formerly sold as BE51941. CD40 belongs to the TNF receptor superfamily. While the biological role of some of the ligand-receptor pairs in this family still remains obscure, CD40 has proven its importance. 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. CD40 Ligand is expressed on the surface of activated CD4+ T cells, basophils, and mast cells. Binding of CD40L to its receptor, CD40, on the surface of B cells stimulates B-cell proliferation, adhesion and differentiation. A soluble isoform of CD40L has been shown to exist in the circulation. This soluble molecule is a homotrimer of a 18kDa protein exhibiting full activity in B cell proliferation and differentiation assays, is able to rescue B cells from apoptosis and binds soluble CD40. CD40L is discussed in relation to a potential role in supporting B cell tumors and it has been discovered that the molecular defect in the Xlinked Hyper-IgM-Syndrome is targeted to the CD40L gene, it is functional involved in B cell hybridomas and chronic lymphocytic leukemia as well as several autoimmune diseases. Synonyms: CD 40 Ligand; TNF ligand superfamily member 5; TNF related activation protein; T cell antigen Gp39; CD154 antigen