Author: V. Dimov, M.D., Fellow, Creighton University Division of Allergy & Immunology
Reviewer: S. Randhawa, M.D., Fellow, LSU (Shreveport) Department of Allergy & Immunology
CD59, or protectin, is a complement regulatory protein that inhibits the complement membrane attack complex (MAC) by binding C5b678 and preventing C9 from binding and polymerizing.
It is present on cells to prevent complement from damaging them.
CD59 is also called membrane attack complex inhibition factor (MACIF) or MAC-inhibitory protein (MAC-IP).
CD59 molecule, complement regulatory protein. Image source: Wikipedia, public domain.
components of the complement, MAC, from perforating the cell membrane
Complement receptors (click to enlarge the image).
Eculizumab (Soliris) is a humanized mAb against complement protein C5. It is used for treatment of paroxysmal nocturnal hemoglobinuria (PNH).