Q: What are the three complement pathways?
A: classical, alternative and terminal

Q: Where are most complement components made?
A: mononuclear phagocytes in liver and tissue

Q: What are the major roles of complement
A: opsonize bacteria, lyse cells and remove immune complexes

Q: Describe the role of C1 in the complement cascade
A: C1q binds IgM or IgG, which activates C1r and C1s, which then cleave C4 and C2

Q: What proteins comprise C3 convertase in the classical and alternative pathways?
A: C4b2a(classical) C3bBb(alternative)

Q: How is C5 activated in the classical pathway?
A: C5 convertase or C4b2a3b

Q: What proteins are involved in the membrane attack complex?
A: C5, C6, C7, C8, C9

Q: When is the alternative pathway used?
A: In the absence of antibodies

Q: What is the role of C3a and C5a?
A: both are anaphylatoxins (dilate blood vessels, contract smooth muscle, allow vascular fluid leakage), C5a is also a PMN attractant

Q: Which complement proteins are the “butter which opsonize”?
A: C3b and C5b

Q: What is a good test for total functional complement activity?
A: ELISA

Q: C3 deficiency leads to what?
A: severe recurrent infections, pneumonia, sepsis, meningitis, fungal infections

Q: C5-C8 deficiencies lead to what?
A: recurrent gonococcal and meningococcal infections

Q: What type of disease is linked to C1q, C1r, C1s, C4 and C2 deficiencies?
A: Lupus like diseases (SLE)