10. Complement - Additional Properties

Question 1

Which complement factors have anaphylatoxin activity?

Answer 1

• C3a, C4a, C5a

Question 2

Which complement protein is a chemotaxin?

Answer 2

• C5a

Question 3

Which complement protein is an opsonin?

Answer 3

• C3b

Question 4

Which complement protein plays a role in immune adherence?

Answer 4

• C3b

- mediates clearance of immune complexes

Question 5

What complement protein is inactivated by Factor I?

Answer 5

• C3b

Question 6

What complement pathways are affected by Factor I?

Answer 6

• all 3 pathways

Question 7

What is the function of the Decay Accelerating Factor, and what pathway does it affect?

Answer 7

• dissociates C3bBb

- affects the alternative pathway

Question 8

Hereditary angioedema is associated with a deficiency in which of the complement proteins?

Answer 8

• deficiency in C1 esterase inhibitor
• decreased C1s inhibitor => increased C1s => increased breakdown of C2 to C2b => increased vasodilation and vasopermeability

Question 9

A patient presents with recurrent Neisserial infections. Quantitative laboratory analysis would likely show a decrease in which of the complement protein(s)?

Answer 9

• deficiencies in late components

- C5, C6, C7, C8

Question 10

What is the name of the laboratory test used to measure the functional activity of the classical pathway of complement?

Answer 10

CH50

Question 11

In order to inactivate complement in a sample of patient serum, the serum would be heated at what temperature? For how long?

Answer 11

• 56 degrees Celsius for 30 min