Complement Component C5 (C5)

Complement component C5 is a crucial glycoprotein in the human complement system, encoded by the *C5* gene. It plays a central role in both innate immunity and inflammatory responses. Upon activation by C5 convertases, it is cleaved into C5a, a potent anaphylatoxin and chemoattractant, and C5b, which initiates the assembly of the membrane attack complex (MAC), leading to cell lysis. C5 is a therapeutic target, with drugs like Eculizumab inhibiting its activation to treat conditions like paroxysmal nocturnal hemoglobinuria and atypical hemolytic uremic syndrome.

Other names

C5Complement component C5C5aC5b

Eculizumab prevents cleavage of C5 into C5a and C5b, thus inhibiting the formation of the membrane attack complex (MAC) and the release of the anaphylatoxin C5a.