1

Complement Pathways

Complement Activation

Proteins are normally inactive -need to be activated (or transient)

Activation - sequential proteolysis

Covalent Attachment - becomestably active after attaching tomicrobe (ab complexes)

Regulation! - important tominimize complement mediateddamage to host cells

2

C1 Inhibitor Regulation

3

Inhibition of C3 Convertase Formation

4

Factor I mediated cleavage of C3b