Complement component 7 is a component of the complement system. It belongs to the complement C6/C7/C8/C9 family. It contains 1 EGF-like domain, 1 LDL-receptor class A domain, 1 MACPF domain, 2 Sushi (CCP/SCR) domains and 2 TSP type-1 domains. Complement component 7 serves as a membrane anchor. It participates in the formation of Membrane Attack Complex (MAC). People with C7 deficiency are prone to bacterial infection. It is a constituent of MAC that plays a key role in the innate and adaptive immune response by forming pores in the plasma membrane of target cells. Defects in C7 are a cause of complement component 7 deficiency (C7D). A rare defect of the complement classical pathway associated with susceptibility to severe recurrent infections, predominantly by Neisseria gonorrhoeae or Neisseria meningitidis.

> 88 % as determined by SDS-PAGE