Recombinant Human CD40L (TNFSF5) (Animal-Free)

CD40L is a type II membrane protein that shares 78% amino acid identity with its mouse counterpart. Human CD40L is a polypeptide of 261 amino acids, consisting of 22, 24, and 215 amino acids for the cytoplasmic, transmembrane, and extracellular domains respectively. Soluble forms of CD40L (sCD40L) have been identified, and a 18 kD fragment has the ability to  form homotrimers and bind to CD40 to induce biological signals.  The 18 kD protein has full activity in B cell proliferation and differentiation assays. Activated platelets express CD40L on their surface and constitute the major source of sCD40L (>95% in blood).  Platelet-derived CD40L regulates neutrophil recruitment and lung damage in sepsis, and it has been suggested that MMP-9 regulates CD40L shedding in abdominal sepsis.  Platelet-associated CD40L has been linked to progression of atherosclerotic disease, and elevated plasma levels of sCD40L in patients seems to be a reliable predictor of cardiovascular events, such as atherosclerotic plaque rupture and acute coronary syndromes. Also, platelet-associated CD40L expression is increased in idiopathic thrombocytopenic purpura patients, and it has been speculated that platelet-associated CD40L drives the activation of autoreactive B lymphocytes in this disease. In addition, high plasma levels of sCD40L have been connected to HIV-associated neurocognitive disorders (HAND).