5 Written Questions

1. cofactor for factor I, inhibits C3 convertase by displacing C2a or inactivating C4b
2. On all rbcs and endo- and epithelial cells. inhibits lysis by binding to C5b-C8 complex, prevents C9 attachment
3. Vitronectin and clusterin. Produced in liver, prevents incorporation of C5b-C8 into cell membrane and subsequent polymerization of C9
4. combines with C1r and C1s to dissociate them from C1q ---> C3 cannot be cleaved, cascade stops
5. Prevents formation of C3b convertase, inhibits binding of factor B to C3b, competes with factor B to bind to C3b; causes dissociation into C3b and Bb, cofactor to factor I to catabolize C3b

4 Multiple Choice Questions

1. Cofactor for factor I in cleaving C4b and C3b
   1. C1 inhibitor
   2. Factor H
   3. Factor I
   4. Complement receptor 1
2. Cofactor to factor I: binds C4b in the classical or binds to C3b in the alternative pathway making them susceptible to Factor I inactivation
   1. Membrane control protein
   2. C4 binding protein
   3. Factor I
   4. Complement receptor 1
3. prolong life of complement fragments or activated molecules, increase half-life of C3bBb
   1. Properdin
   2. Factor I
   3. CR2 (CD21)
   4. Factor H
4. only receptor found on RBCs, receptor for C3b(acts in immune adherence), cofactor to factor I in cleaving C4b and C3b, activity with both C3 and C5 convertase, on RBC will bind complement-bearing immune complexes to transport them to phagocytic cells, deficiency of CR1 may lead to lupus
   1. CR1 (CD35)
   2. Properdin
   3. CD59
   4. CR2 (CD21)

4 True/False Questions

1. Factor I → Prevents formation of C3b convertase, inhibits binding of factor B to C3b, competes with factor B to bind to C3b; causes dissociation into C3b and Bb, cofactor to factor I to catabolize C3b

   True        False

2. CR2 (CD21) → found on B lymphs and follicular dendritic cells, reacts with iC3b and C3dg

   True        False

3. Homologous restriction factor → on RBCs: protect against lysis. Facilitate dissociation of C3 convertase in the classical/alternative pathway

   True        False

4. Decay accelerating factor → protein on the RBC, WBC, and platelet membrane. Inhibits channel formation

   True        False