Complement Qs 7-11

Question 1

In the membrane attack phase of the classical complement pathway, the role of C5b is to:

Answer 1

Initiate formation of the MAC.

Question 2

Complement receptor (CR):

Answer 2

On erythrocytes remove immune complexes from the circulation.

Question 3

As complement is activated by complexes of antibody-coated bacteria, bystander lysis of nearby host cells is prevented by:

Answer 3

proteins on host cell membranes that inhibit MAC formation.

Question 4

Complement activity is restricted by all of the following except:

Answer 4

LPS in the outer membrane of Gram-negative bacteria that inactivates C3b.

Question 5

A deficiency in complement proteins or in their regulators can result in:

Answer 5

Blood in the urine from erythrocyte lysis, decreased levels of certain complement proteins in the circulation, immune complex disease, increased number of infections.