Question 1

A decreased CH50 and a decreased AH50 would indicate a low amount of which of the following complement components?

Accepted Answer

A)  C4 
B)  C3 
C)  C4 binding protein 
D)  Factor B

Question 2

The C5 convertase of the classical pathway of complement activation is:

Accepted Answer

A)  C3bBbP. 
B)  C3bBb3bP. 
C)  C4b2a3b. 
D)  C4b2a.

Question 3

Which factors are only associated with the alternative pathway?

Accepted Answer

A)  Factor B and factor D 
B)  Factor D and C3 
C)  Factor B and C2 
D)  C2 and MBL

Question 4

A patient has an abnormal alternative pathway activation pattern.Which of the following complement proteins should be assessed to further investigate the problem?

Accepted Answer

A)  C1 
B)  C2 
C)  C3 
D)  C4

Question 5

The C3 convertase of the alternative pathway of complement activation is:

Accepted Answer

A)  C3bBbP. 
B)  C3bB. 
C)  C4b2a3b. 
D)  C4b2a.

Question 6

Which protein inhibits the classical complement pathway at the very beginning of the pathway?

Accepted Answer

A)  C1INH 
B)  C4BP 
C)  C3BP 
D)  Factor H

Question 7

Which factor is unique to the lectin pathway?

Accepted Answer

A)  Factor B 
B)  C1q 
C)  Mannose-binding protein 
D)  Factor I

Question 8

The C5 convertase of the alternative pathway of complement activation is:

Accepted Answer

A)  C4b. 
B)  C4b2a. 
C)  C4b2a3b. 
D)  C3bBb3bP.

Question 9

Which of the following is an important function of the complement system?

Accepted Answer

A)  Stimulation of growth of T cells 
B)  Decrease in vascular permeability 
C)  Clearance of antigen-antibody complexes 
D)  Increased production of antibody

Question 10

Which complement receptor is involved in mediating phagocytosis?

Accepted Answer

A)  CR1 
B)  CR2 
C)  CR3 
D)  CR4

Question 11

Identify the true statement about C3.

Accepted Answer

A)  It is known as the recognition unit. 
B)  It plays a key role in all pathways. 
C)  It is the least abundant of the complement proteins. 
D)  Its major function is antigen recognition.

Question 12

Select the test that could be used to determine whether a patient has a specific deficiency in C3.

Accepted Answer

A)  CH50 
B)  AH50 
C)  Radial immunodiffusion 
D)  Hemolytic titration assay

Question 13

Which of the following activities is associated only with the alternative pathway of complement fixation?

Accepted Answer

A)  Formation of a membrane attack unit 
B)  Factor B and C3b combination 
C)  Antigen-antibody combination 
D)  Lysis

Question 14

The recognition unit in the classical complement pathway consists of:

Accepted Answer

A)  C4b2a3b. 
B)  C5b6789. 
C)  C1qrs. 
D)  factor B

Question 15

Which of the following is referred to as C5 convertase?

Accepted Answer

A)  C4b2a 
B)  MASP1 
C)  C4b2a3b 
D)  C1qrs

Exam 7: Complement System