Complement

Question 1

Deficiency in C1, C2, C4

Answer 1

immune-complex disease

Question 2

Deficiency in C3

Answer 2

susceptibility to encapsulated bacteria

Question 3

Deficiency in C5-C9

Answer 3

Susceptibility to Neisseria

Question 4

Deficiency in factor D or properdin (factor P)

Answer 4

• susceptibility to encapsulated bacteria and Neisseria

- No immune-complex disease

Question 5

immune complex

Answer 5

antibody binding to antigen

Question 6

Deficiency in factor I

Answer 6

susceptibility to encapsulated bactera

Question 7

How do deficiencies in C3 and Factor 1 happen?

Answer 7

have too much binding –> these factors get used up

Question 8

Deficiency in DAF, CD59

Answer 8

Autoimmune-like conditions including paroxysmal nocturnal hemogobinuria

Question 9

Deficiency in C1INH

Answer 9

hereditary angiodema (HAE)

Question 10

What does a loss of early classical complement pathway components lead to? What doesn’t it lead to?

Answer 10

• leads to immune complex-like disease
• NOT increased rate of bacterial infections
• just can’t clear the complexes, but they form

Question 11

C5a

Answer 11

most important complement component for mediating inflammation

Question 12

opsonization

Answer 12

critical role of complement

Question 13

terminal complement reaction

Answer 13

• cleavage of C3

- necessary to kill Neisseia bacteria

Question 14

how are immune complexes cleared

Answer 14

complement

Question 15

complement membrane attack complex

Answer 15

• C5-C9

- lysis of target cell after C3 has been cleaved

Question 16

cleavage of C3 –>

Answer 16

• C3a recruits phagocytes

- C3b tags bacterium for destruction

Question 17

in classical complement, what cleaves C3

Answer 17

C2a:C4b complex

Question 18

CR1

Answer 18

phagocytosis

Question 19

iC3Bb

Answer 19

soluble C3 convertase, initiates alternative pathway

Question 20

chemoattractant complement protein

Answer 20

C5 (C5a)

Question 21

alternative complement pathway

Answer 21

• properdin stabilizes C3bBb (C3 convertase) on pathogen surface
• factors H and I inactivate C3b –> iC3b
• DAF and MCP disrupt C3bBb (C3 convertase) on self cell surface

Question 22

CR1 and CR3

Answer 22

CR1 on macrophage binds CR1 on bacterium

Question 23

C3a, C5a

Answer 23

anaphylatoxin - histamine release for mast cells, increase vascular permeability

Question 24

C5a

Answer 24

chemotaxis - attract polymorphonuclear leukocytes and macrophages

Question 25

inactivate alternative complement

Answer 25

C1INH

-inactivates CIr and C1s

Question 26

inactivate classical complement

Answer 26

C4-binding protein and factor I inactivate C3 convertase