CD40 Ligand (TRAP cleavage) (CD40L) (CD154)

TRAP cleavage (CD40 Ligand), a 35kDa ligand, is transiently expressed on the surface of T-cells and binds to CD40, which is expressed on the surface of B-cells. This binding event leads to the differentiation, proliferation, and isotype switching of the B-cells. The physiological importance of CD40L has been demonstrated by the fact that expression of defective CD40L protein causes an immunodeficiency state characterized by high IgM and low IgG serum levels, indicating faulty T-cell dependent B-cell activation (1). Abnormalities in the CD40L gene are associated with an X-linked immunodeficiency in humans [hyper-IgM (immunoglobulin M) syndrome]. This disease is characterized by elevated concentrations of serum IgM and decreased amounts of all other isotypes (2). This CD40L is expressed on activated T cells, mostly CD4+ but also some CD8+ as well as basophils/mast cells. Cross-linking of CD40 with immobilized anti-CD40 or cells expressing CD40L induces B cells to proliferate strongly, and addition of IL-4 or IL-13 allows the generation of factor-dependent long-term normal human B cell lines and the secretion of IgE following isotype switching (3). Applications: Suitable for use in Western Blot, Flow Cytometry. Other applications not tested. Recommended Dilution: Western Blot: 1:5000 Flow Cytometry: 1:40 Optimal dilutions to be determined by the researcher. Storage and Stability: May be stored at 4 degrees C for short-term only. For long-term storage, aliquot and store at -20 degrees C. Aliquots are stable for at least 12 months at -20 degrees C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer. Manufactured incorporating RabMAb(R) technology under Epitomics US patents, No 5,675,063 and 7,429,487, owned by Abcam.