This set of Immunology Multiple Choice Questions & Answers (MCQs) focuses on “Regulation of Complement Activity and Complement Deficiencies”.
1. Where are the complement control proteins present?
a) Blood serum
b) Blood plasma
c) Lymph
d) Lymphatic plasma
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Explanation: Complement control proteins are the proteins that help in regulating the complement activity. These are present in blood plasma at higher concentrations than the complement proteins themselves.
2. Which of the following is called protectin?
a) CD24
b) CD59
c) CD19
d) CD16
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Explanation: CD59, which is known as protectin, is an example of the complement control proteins which are present on the membranes of self-cells. CD59 inhibits polymerisation of C9.
3. Inhibiting C9 polymerisation is the function of___________
a) CD24
b) CD59
c) CD19
d) CD16
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Explanation: CD59 or protectin is an inhibitor of C9 polymerisation and ultimately MAC formation. The inhibition is done by initially inhibiting C3 convertase. CD55 also takes part in it.
4. Which of the following inhibits the classical pathway?
a) C1-inhibitor
b) C2-inhibitor
c) C3-inhibitor
d) C4-inhibitor
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Explanation: C1-inhibitor is a protein which inhibits the classical pathway right from the initial stages. It binds to C1 to prevent its activation.
5. What is the function of the Decay Accelerating Factor (DAF)?
a) Inhibits C2 cleavage
b) Inhibits C4 cleavage
c) Inhibits C3 convertase
d) Inhibits C5 convertase
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Explanation: C3 convertase inhibition is occurred via the factor called Decay Accelerating Factor (DAF). It is bound to erythrocyte plasma membrane.
6. N.gonorrhoeae is caused due to deficiency of _________
a) C3
b) Factor B
c) Factor D
d) MAC
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Explanation: Many cases have been reported regarding the MAC deficiency associated diseases. Some of them are N.gonorrhoeae, N.meningitidis and some autoimmune diseases.
7. Which of the following factors are associated with Hemolytic uremic syndrome?
a) Factor I
b) Factor B
c) Factor D
d) Factor H
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Explanation: Factor H is a complement regulator. Factor H and membrane cofactor protein mutations can cause hemolytic uremic syndrome which usually includes bloody diarrhea.
8. Which of the following diseases is caused by mutations in C1 inhibitor?
a) Marfan syndrome
b) Hemochromatosis
c) Hereditary angioedema
d) Huntington’s disease
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Explanation: Hereditary angioedema is a disease due to the mutations in C1 inhibitor. This is caused due to the reduced regulation of bradykinin by C1-INH.
9. Complement mechanism does not deal with the rejection of transplanted organs. True/False?
a) True
b) False
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Explanation: Complement system plays a main role in the rejection of transplanted organs by triggering some inflammatory responses. It is called AMR, Antibody Mediated Rejection.
10. Is the complement system implicated in diseases like Alzheimer’s disease?
a) Yes
b) No
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Explanation: The complement system is believed to be involved in causing Alzheimer’s disease and also other neurodegenerative diseases like spinal cord injuries.
11. Polymorphism of a single nucleotide in Factor H can cause __________
a) Rejection of transplanted organs
b) Eye disease – age related
c) Nerve weakness
d) Tissue damages
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Explanation: Mutation in most of the complement systems cause various diseases. Polymorphism in Factor H causes eye disease age related macular degeneration. These are thought to be caused because of deviated complement behaviour.
12. Which of the following is associated with regulating mast cell-ASM cell interaction?
a) C2a
b) C3a
c) C2b
d) C3b
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Explanation: Asthma associated with complement cascade which includes the regulation of mast cell-ASM (Airway Smooth Muscle) cell interaction by C3a.
13. Barraquer-Simons syndrome is caused due to the low serum levels of _______
a) C5
b) C4
c) C3
d) C2
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Explanation: Barraqyer-Simons syndrome, a rare form of acquired lipodystrophy, is caused due to the low serum of the complement component 3, i.e., C3.
14. Which of the following antibodies are associated with complement activation?
a) IgA and IgD
b) IgG and IgE
c) IgM and IgA
d) IgG and IgM
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Explanation: IgG and igM are the freely circulating antibodies in the body. They mediate in complement activation by opsonizing the pathogens for phagocytosis.
15. Which of the following deficiencies cause the complement mediated self-attack?
a) CD16
b) CD35
c) CD28
d) CD46
View Answer
Explanation: CD46 is a membrane cofactor protein which mediates the cleavage of C3b and C4b. Deficiency of CD46 is a predisposing factor which can cause complement mediated self-attack.
Sanfoundry Global Education & Learning Series – Immunology.
To practice all areas of Immunology, here is complete set of 1000+ Multiple Choice Questions and Answers.
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