EXAM 2 The Complement System

Question 1

what are the 7 main pattern recognition molecules?

Answer 1

• initiators
• convertase activators
• opsonins
• anaphylatoxins
• membrane attack complex
• complement receptors
• regulators

Question 2

what do initiators do?

Answer 2

• initiate the complement pathways
• classical pathway: antibody/C1q complexes
• lectin pathway: mannose - binding lectins
• alternate pathway: C3, properdin

Question 3

what do convertase activators do?

Answer 3

form convertases, which label pathogens/antigens with C3b and C5b

Question 4

what do opsonins do?

Answer 4

coat pathogens/antigens and target them for phagocytosis

Question 5

what do anaphylatoxins do?

Answer 5

initiate and promote inflammation

Question 6

what does the membrane attack complex do?

Answer 6

forms the MAC pore

Question 7

what do complement receptors do?

Answer 7

initiate signaling

Question 8

what do regulators do?

Answer 8

• restrict or halt complement activity

Question 9

what protein initiates the classical pathway?

Answer 9

C1

Question 10

what are the 3 complement pathways, and in what order do they each act?

Answer 10

1. alternative pathway
2. lectin pathway
3. classical pathway

Question 11

what is a convertase?

Answer 11

a protease that continuously cleaves its complement component

Question 12

the lectin pathway targets pathogen cell surface ___

Answer 12

carbohydrates

Question 13

the lectin pathway is initiated by what?

Answer 13

mannose binding lectins (MBLs) and ficolins

Question 14

the lectin pathway recruits what?

Answer 14

• MBL associated serine proteases (MASP)
  
  • MASP-1
  • MASP-2

Question 15

in the lectin pathway, serine proteases cleave which complement protein?

Answer 15

C4

Question 16

what are the 3 routes of activation of the alternative pathway?

Answer 16

1. spontaneous C3 hydrolysis
2. properdin-pathogen binding and C3 recruitment
3. proteolytic C3 cleavage
   
   1. thrombin
   2. clotting cascade proteases