Description: CD40 ligand (CD40L, also known as CD154, TRAP or gp39) is a membrane glycoprotein expressed on activated CD4+ T-cells, NK cells, mast cells, basophils and eosinophils. The CD40-CD40L interaction stimulates B cell immune responses including cell surface antigen expression, cell cycle activation, Ig isotype switching, Ig secretion and memory generation. The CD40-CD40L interaction also plays important roles in monocyte and dendritic cell activation, T-cell co-stimulation and cytokine production. It has been reported that the CD40-CD40L interaction is involved in the pathogenesis of amyloid pathology in Alzheimer disease. E. coli-produced recombinant mouse CD40L is a non-glycosylated polypeptide of 149 amino acids comprising the soluble extracellular domain of CD40L.