CD59

CD59 glycoprotein also known as MAC-inhibitory protein (MAC-IP), membrane inhibitor of reactive lysis (MIRL), protectin, or Homologous restriction factor(HRF) is a is_associated_with::protein that in humans is encoded by the CD59 is_associated_with::gene.

CD59 attaches to host cells via a is_associated_with::glycophosphatidylinositol (GPI) anchor. When complement activation leads to deposition of C5b678 on host cells, CD59 can prevent C9 from polymerizing and forming the is_associated_with::complement membrane attack complex. Mutations affecting GPI that reduce expression of CD59 and is_associated_with::decay-accelerating factor on is_associated_with::red blood cells result in is_associated_with::paroxysmal nocturnal hemoglobinuria.

is_associated_with::Viruses such as is_associated_with::HIV, human is_associated_with::cytomegalovirus and vaccinia incorporate host cell CD59 into their own is_associated_with::viral envelope to prevent lysis by complement.