Complement 1 - 11

Question 1

Complement:

Answer 1

Participates in both innate and adaptive immune responses.

Question 2

Complement is involved in all of the following except:

A. attraction of neutrophils to an infection site.
B. increased presence of serum proteins in the infected tissues.
C. lysis of bacteria in the absence of specific antibodies.
D. opsonization of microorganisms for phagocytosis.
E. sensitization of T cells to antigen.

Answer 2

E. sensitization of T cells to antigen.

Question 3

Complement is:

Answer 3

Present in the circulation in an inactive form.

Question 4

The alternative pathway of complement activation:

Answer 4

Requires C3.

Question 5

If a person is born without C2 and C4:

Answer 5

The amount of C3b produced during bacterial infections will be reduced.

Question 6

Which of the following are least sensitive to complement-mediated lysis?

A. enveloped viruses.
B. erythrocytes
C. gram negative bacteria.
D. Gram positive bacteria
E. leukocytes

Answer 6

D. Gram positive bacteria

Question 7

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

Answer 7

Initiate formation of the MAC.

Question 8

Complement receptors (CR):

Answer 8

on erythrocytes remove immune complexes from the circulation.

Question 9

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

Answer 9

Protein in host cells membranes that inhibit MAC formation.

Question 10

Complement activity is restricted by all of the following EXCEPT:

A. dissociation of C3 and C5 convertases.
B. gram positive cell walls that are resistant to MAC polymerization.
C. host cell plasma proteins that inactivate C3a, C4a, and C5a activity.
D. LPS in the outer membrane of Gram negative bacteria that inactivates C3b.
E. proteolytic cleavage of complement proteins into smaller fragments.

Answer 10

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

Question 11

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

Answer 11

A. blood in the urine from erythrocyte lysis.
B. decreased levels of certain complement proteins in the circulation.
C. immune complex disease.
D. increased numbers of infections.

E. All of the above can result from complement deficiensies!!!!!!!!!!!! (on MCQ, this is the correct one)