Complement

Question 1

What does complement work more effectively with?

Answer 1

bacterial infection than parasitic or viral

Question 2

How are complement proteins activated (simple?)?

Answer 2

cleaved

Question 3

What is produced when complement proteins are cleaved?

Answer 3

2 cell fragments, a and b

Question 4

Which fragment of the complement protein is smaller?

Answer 4

a

Question 5

What are the functional categories of complement proteins?

Answer 5

• initiators
• enzymatic mediator
• opsonins
• inflammatory mediators
• membrane attack proteins
• receptor proteins
• regulatory proteins

Question 6

What do initiators do?

Answer 6

initiate complement cascade

Question 7

What do enzymatic mediators do?

Answer 7

cleave and activate other complement proteins

Question 8

What do opsonins do?

Answer 8

enhance phagocytosis

Question 9

What do inflammatory mediators do?

Answer 9

enhance blood supply to areas of infection

Question 10

What do membrane attack proteins do?

Answer 10

form membrane attack complexes called MACs

Question 11

What do receptor proteins do?

Answer 11

located on cell surfaces, bind other complement proteins

Question 12

What do regulatory proteins?

Answer 12

protect healthy cells from effects of complent

Question 13

What 3 ways does complement activation occur?

Answer 13

• classical pathway
• lectin pathway
• alternative pathway

Question 14

What is the classical pathway of activation?

Answer 14

• antigen-antibody complexes bind initiator proteins which activates complement cascade
• considered adaptive immunity because utilizes antibodies

Question 15

What is the lectin pathway of activation?

Answer 15

• initiator proteins bind to lectins on bacteria
• activates complement cascade

Question 16

What is the alternative pathway of activation?

Answer 16

• complement cascade is initiated with spontaneous cleavage of C3 (complement protein 3)

Question 17

What is lectin?

Answer 17

carbohydrate structures

Question 18

What are the 3 functions of complement?

Answer 18

• Membrane attack complex (MAC)
• Opsonization
• Promotion of inflammation

Question 19

What does Membrane Attack Complexes do?

Answer 19

• complement proteins embed into bacterial cell membrane
• causes holes to form in bacterial membrane
• water and salts diffuse into cell causing cell to burst

Question 20

What is opsonization?

Answer 20

• cleaved complement proteins can bind to bacteria, marking it for phagocytosis
• receptors on phagocytic cells bind to complement protein opsonins and this initiates phagocytosis

Question 21

How does complement promote inflammation?

Answer 21

smaller complement fragments bind to receptors on innate immune cells

Question 22

What does smaller complement fragments binding to receptors on inmate immune cells result in?

Answer 22

• release of TNF-alpha and IL-6
• degranulation of granulocytes

Question 23

What does the release of TNF-alpha and IL-6 result in?

Answer 23

increase in vascular permeability and vasodilation

Question 24

What are the granulocytes?

Answer 24

neutrophils, eosinophils, basophils, mast cells

Question 25

What is the purpose of degranulation of granulocytes?

Answer 25

granules contain:
- antimicrobial proteins
- proteins that increase vascular permeability and cause vasodilation