Immunology - Complement Pathway (6)
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- 1.Regarding the complement pathway, which one of the following is the most accurate?
- A.
C3 convertase protects normal cells from lysis by complement.
- B.
C3a is a decay-accelerating factor and causes the rapid decay and death of bacteria.
- C.
In general, gram-positive bacteria are more likely to be killed by complement than gram-negative bacteria.
- D.
The membrane attack complex is formed as a result of activation of the classic pathway but not by activation of the alternative pathway.
- E.
The first time a person is exposed to a microorganism, the alternative pathway of complement is more likely to be activated than the classic pathway.
- 2.Of the following complement components, which one is the most important opsonin?
- A.
C1
- B.
C3a
- C.
C3b
- D.
C5a
- E.
C5b
- 3.Of the following complement components, which one is the most potent in attracting neutrophils to the site of infection (i.e., acting as a chemokine)?
- A.
C1
- B.
C2
- C.
C3b
- D.
C5a
- E.
Mannan-binding lectin
- 4.Of the following, which one is the most important function of the complex formed by complement components C5b,6,7,8,9?
- A.
To enhance antibody production
- B.
To inhibit immune complex formation
- C.
To opsonize viruses
- D.
To perforate bacterial cell membranes
- E.
To release histamine from mast cells
- 5.A deficiency of which one of the following complement components predisposes to bacteremia caused by members of the genus Neisseria?
- A.
C1
- B.
C3b
- C.
C5a
- D.
C5b
- E.
C5b,6,7,8,9
- 6.Your patient is a 20-year-old woman who complains of swellings on her arms and legs and a feeling of fullness in her throat that makes it difficult to breath. The swellings are not red, hot, or tender. You suspect she may have angioedema caused by a complement abnormality. Of the following, which one is the most likely explanation?
- A.
She has too little C1 inhibitor.
- B.
She has too little C3b.
- C.
She has too little factor B.
- D.
She has too much C5a.
- E.
She has too much C9.
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