Complement and Complement Disorders

Question 1

Function of MAC

Answer 1

Membrane Attack Complex defends against gram-negative bacteria

Question 2

Classic pathway

Answer 2

Mediated by IgG and IgM

Question 3

Alternative pathway

Answer 3

Mediated by microbe surface molecules

Question 4

Lectin pathway

Answer 4

Mediated by mannose or other sugars on microbe surface

Question 5

Components of Complement

Answer 5

C3b, C3a, C4a, C5a, C5b, C6-C9

Question 6

Function of C3b

Answer 6

Opsonization; C3b binds bacteria

Question 7

Function C3a,C4a, C5a

Answer 7

Anaphylaxis

Question 8

Function of C5a

Answer 8

Neutrophil chemotaxis

Question 9

Function of C5b, C6-C9

Answer 9

cytolysis by MAC

Question 10

Two primary opsonins in bacterial defense by enhancing phagocytosis

Answer 10

C3b and IgG

Question 11

Opsonin that helps clear immune complexes

Answer 11

C3b

Question 12

Inhibitors that prevent complement activation on self cells

Answer 12

C1 esterase inhibitor and Decay-accelerating factor (DAF) aka CD55

Question 13

Complement protein deficiency that increases susceptibility to type III hypersensitivity reactions

Answer 13

C3 deficiency

Question 14

Complement protein deficiency that increases risk of severe, recurrent pyogenic sinus and respiratory tract infections

Answer 14

C3 deficiency

Question 15

Terminal complement deficiency that increases susceptiility to recurrent Neisseria bacteremia

Answer 15

C5-C9 deficiencies

Question 16

Complement regulatory protein deficiency causing hereditary angioedema

Answer 16

C1 esterase inhibitor deficiency

Question 17

Mechanism of hereditary angioedema in C1 esterase inhibitor deficiency

Answer 17

Unregulated activation of kallikerin leading to increased bradykinin

Question 18

What drug is contraindicated in C1 esterase inhibitor deficiency

Answer 18

ACE inhibitors

Question 19

C1 esterase inhibitor deficiency is charaterized by…

Answer 19

Decreased C4 levels

Question 20

Complement regulatory protein deficiency causing complement-mediated lysis of RBCs and paroxysmal nocturnal hemoglobinuria

Answer 20

CD55 deficiency (DAF deficiency)