Complement component C9 (human) monoclonal antibody (C9 53)

Complement factor C9 is a 71kDa single-chain ellipsoid a-globular molecule of 558 amino acids including a leader sequence of 20 amino acids. C9 binds the C5b8 complex on membranes and has the unique function of forming tubular structures containing between 12 and 18 monomers, closely resembling the membrane attack complex (MAC). The primary site of synthesis is hepatocytes; secondary sites are monocytes, fibroblasts and glial cells. The normal level of C9 in plasma is 60 �g/mL, and the level is up regulated from hepatocytes by IFN-g.