Decay-Accelerating Factor

Abstract CD55 or decay-accelerating factor (DAF) is a 70 kDa glycoprotein consisting of four complement control protein (CCP) domains with a single N -linked glycosylation site between CCP1 and 2, a heavily O -glycosylated membrane proximal domain rich in serine, threonine and proline and a glycosylphosphatidylinositol (GPI) anchor. DAF is present on most cell types and intrinsically functions to protect the host cell from autologous complement attack by preventing the formation and accelerating the decay of the classical and alternative C3 and C5 convertases. DAF deficiency is linked to several diseases including paroxysmal nocturnal haemoglobinuria, as well as autoimmune diseases.