(C5b, C6, C7, C8, C9)

Membrane Attack Complex

CHAPTER 35, FIGURE 22 Initiation of action by complement occurs via three pathways: classical, alternative

(properdin), and lectin pathways.

CHAPTER 35, FIGURE 23 A cartoon representation of complement protein Cl. The Cl complex consists of

one Clq, two Clr, and two Cls molecules. The formation of the complex requires the presence of Ca2+. Clq contains

six polypeptide chains that form a globular structure that binds to antigen-antibody complexes at one end of each

chain.