[MCQ] HIV / AIDS- Part 4

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HIV / AIDS- Part 4

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Congratulations - you have completed HIV / AIDS- Part 4. You scored %%SCORE%% out of %%TOTAL%%. Your performance has been rated as %%RATING%%

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Question 1

What proportion of HIV/AIDS patients are females ?

A	~ 10 %
B	~ 33 %
C	~ 50 %
D	~ 66 %

Question 1 Explanation:

Among people living with HIV/AIDS, ~50% are female.

Question 2

Which one of the following statements about ‘Dendritic cells’ is false ?

A	Capture antigens in bone marrow
B	Transport captured antigens to lymphoid organs
C	Digest captured antigens & display resulting peptides to T cells
D	Moderately susceptible to HIV infection because they express low levels of CD4, CXCR4 & CCR5

Question 3

Which of the following about Dendritic cells is false ?

A	Play a role in initiation of HIV infection
B	Express C-type lectin receptors (DC-SIGN)
C	Can trap HIV & mediate transinfection of CD4+ T cells
D	None of the above

Question 4

Which of the following about DC-SIGN is false ?

A	Expressed by Langerhans cells
B	DC-SIGN binds with high affinity to HIV envelope gp120
C	Facilitates CD4-mediated infection of dendritic cells
D	DC-SIGN allows efficient infection by aggregating virus on surface of dendritic cells

Question 4 Explanation:

DC-SIGN (dendritic cell-specific intercellular adhesion molecule 3-grabbing nonintegrin) is expressed on dendritic cells. Langerhans cells belong to the family of Dendritic cells

Question 5

Receptor that is abundantly expressed by macrophages facilitating HIV infection is ?

A	Heparan sulfate proteoglycans - Syndecan
B	DC-SIGN
C	CD90
D	CD8+

Question 6

Which of the following is the hallmark of HIV infection ?

A	Aberrant immune activation
B	Chronic, persistent infection
C	Profound immunodeficiency
D	All of the above

Question 6 Explanation:

HIV is an RNA virus whose hallmark is the reverse transcription of its genomic RNA to DNA by the enzyme reverse transcriptase. Aberrant immune activation and Chronic, persistent infection are also hallmarks of HIV infection. Profound immunodeficiency resulting from a progressive quantitative & qualitative deficiency of helper T cells. HIV is an RNA virus whose hallmark is the reverse transcription of its genomic RNA to DNA by the enzyme reverse transcriptase

Question 7

Which of the following is essential for efficient fusion & entry of HIV-1 into its target cells ?

A	CD4 molecule
B	CCR5
C	CXCR4
D	All of the above

Question 8

What proportion of individuals with primary HIV infection experience the “acute HIV syndrome” ?

A	~ 10 %
B	~ 25 %
C	~ 50 %
D	~ 75 %

Question 8 Explanation:

~ 50 % of individuals with primary HIV infection experience the “acute HIV syndrome”. They have high levels of viremia.

Question 9

Acute HIV syndrome symptoms resemble which of the following ?

A	Serum sickness like symptoms
B	Flu-like symptoms
C	Acute mononucleosis-like symptoms
D	Any of the above

Question 9 Explanation:

Acute mononucleosis-like symptoms are well correlated with the presence of HIV viremia.

Question 10

Slope of HIV disease progression correlate with the set point of the level of steady-state plasma viremia after how many months of infection ?

A	~ 3 months
B	~ 6 months
C	~ 12 months
D	~ 18 months

Question 10 Explanation:

Level of steady-state viremia is called the viral set point which correlate with the slope of HIV disease progression. Viral set point at ~1 year has important prognostic implications for the progression of HIV disease. HIV-infected individuals who have a low set point at 6 months to 1 year progress to AIDS much more slowly than individuals whose set point is very high. Levels of viremia generally increase and level of CD4+ T cells in the blood decreases as disease progresses

Question 11

Chronicity associated with persistent virus replication is seen in ?

A	HIV infection
B	HBV infection
C	HCV infection
D	All of the above

Question 11 Explanation:

Chronicity associated with persistent virus replication is seen in HIV, HBV and HCV infections.

Question 12

What is the mechanism of HIV infection to evade elimination by the immune system ?

A	Selection of mutants that escape control by CTLs
B	High rate of replication & continual mutation of virus
C	Disappearance of clones of CD8+ CTLs
D	All of the above

Question 12 Explanation:

Initial burst of viremia brings about several processes that help HIV survive. They are selection of mutants that escape control by CD8+ cytolytic T lymphocytes (CTLs), high rate of virus replication

Question 13

Mechanism by which HIV evades neutralizing responses is ?

A	Hypervariability in primary sequence of the envelope
B	Extensive glycosylation of the envelope
C	Conformational masking of neutralizing epitopes
D	All of the above

Question 13 Explanation:

Envelope proteins gp120 and gp41 are the principal targets of neutralizing antibodies against HIV. HIV employs three mechanisms to evade neutralizing responses: hypervariability in primary sequence of the envelope, extensive glycosylation of the envelope & conformational masking of neutralizing epitopes.

Question 14

Which of the following acts as a latent reservoir of HIV infected cells ?

A	Lymphoid tissue
B	Peripheral blood
C	CNS
D	All of the above

Question 14 Explanation:

Reservoirs of HIV infected cells, latent or otherwise, exist in lymphoid tissue, peripheral blood & CNS.

Question 15

Half-life of a circulating HIV virion is ?

A	~ 30 - 60 minutes
B	~ 60 - 90 minutes
C	~ 90 - 120 minutes
D	~ 120 - 180 minutes

Question 15 Explanation:

Half-life of a circulating virion is ~30–60 min and that of productively infected cells is 1 day.

Question 16

What quantity of HIV virions are produced and cleared from the circulation each day ?

A	~ 1010 – 1011 virions
B	~ 1011 – 1012 virions
C	~ 1012 – 1013 virions
D	~ 1013 – 1014 virions

Question 16 Explanation:

Through studies of relatively steady level of plasma viremia and of infected cells, it is shown that ~1010 - 1011 virions are produced and cleared from the circulation each day.

Question 17

Minimal duration of the HIV-1 replication cycle in vivo is ?

A	~ 2 days
B	~ 7 days
C	~ 14 days
D	~ 21 days

Question 17 Explanation:

The minimal duration of the HIV-1 replication cycle in vivo is ~2 days

Question 18

With ARV therapy, decrease in virus replication occurs in ?

A	Spleen
B	Lymph nodes
C	Peripheral blood
D	All of the above

Question 18 Explanation:

Decrease in plasma viremia after ARV therapy correlates closely with a decrease in virus replication in lymph nodes, confirming that lymphoid tissue is the main site of HIV replication and the main source of plasma viremia.

Question 19

CDC case definition of AIDS includes all HIV-infected individuals with CD4+ T cell counts ?

A	< 200 / μL
B	< 250 / μL
C	< 300 / μL
D	< 350 / μL

Question 19 Explanation:

CDC case definition of AIDS includes all HIV-infected individuals with CD4+ T cell counts < 200 / μL.

Question 20

Median time from primary HIV infection to development of AIDS in untreated patients in developed world is ?

A	~ 3 years
B	~ 5 years
C	~ 10 years
D	~ 15 years

Question 20 Explanation:

The median time from primary HIV infection to the development of AIDS in untreated individuals in the developed world is ~10 years.

Question 21

Individuals are considered to be long-term survivors if they remain alive for how many years after initial infection ?

A	5
B	10
C	15
D	20

Question 21 Explanation:

Individuals are considered to be long-term survivors if they remain alive for 20 years after initial infection. Previously, it was 10 - 15 years.

Question 22

Which of the following is not a characteristic feature of long-term nonprogressor ?

A	Infected with HIV for a long period (>10 years)
B	CD4+ T cell counts in the normal range
C	Received ARV therapy
D	Relatively low, but detectable levels of plasma viremia

Question 22 Explanation:

Characteristic features of long-term nonprogressor are : infected with HIV for a long period (>=10 years), CD4+ T cell counts in normal range, who had not received ARV therapy, relatively low detectable levels of plasma viremia, normal immune function, normal-appearing lymphoid tissue architecture on lymph node biopsy. In general, long-term nonprogressors manifested robust HIV-specific immune responses, both humoral (neutralizing antibodies) and cell-mediated (HIV-specific CTLs). Long-term nonprogressors are by definition long-term survivors, however, the reverse is not always true.

Question 23

Elite nonprogressors have HIV RNA levels of ?

A	< 50 copies per milliliter
B	< 100 copies per milliliter
C	< 150 copies per milliliter
D	< 200 copies per milliliter

Question 23 Explanation:

Elite nonprogressors have HIV RNA levels < 50 copies per milliliter.

Question 24

Which of the following plays a direct role in restriction of virus replication ?

A	HLA B*3701
B	HLA B*4701
C	HLA B*5701
D	HLA B*6701

Question 24 Explanation:

HLA B*5701 or HLA B*2705 alleles plays a direct role in restriction of virus replication

Question 25

Host genetic factors that delay the progression of HIV disease include all except ?

A	Heterozygosity for CCR5-32 deletion
B	Heterozygosity for CCR2-64I mutation
C	Heterozygosity for SDF1-3’A mutation
D	Heterozygosity for RANTES-28G mutation

Question 25 Explanation:

Host genetic factors that delay the progression of HIV disease include heterozygosity for CCR5- 32 deletion, heterozygosity for CCR2-64I mutation, homozygosity for SDF1-3’A mutation and heterozygosity for RANTES-28G mutation.

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See all quizzes of HIV / AIDS- Part 4 here:

1 What proportion of HIV/AIDS patients are females ?
A. ~ 10 %
B. ~ 33 %
C. ~ 50 %
D. ~ 66 %

2 Which one of the following statements about ‘Dendritic cells’ is
false ?
A. Capture antigens in bone marrow
B. Transport captured antigens to lymphoid organs
C. Digest captured antigens & display resulting peptides to T cells
D. Moderately susceptible to HIV infection because they
express low levels of CD4, CXCR4 & CCR5
3 Which of the following about Dendritic cells is false ?
A. Play a role in initiation of HIV infection
B. Express C-type lectin receptors (DC-SIGN)
C. Can trap HIV & mediate transinfection of CD4+ T cells
D. None of the above
4 Which of the following about DC-SIGN is false ?
A. Expressed by Langerhans cells
B. DC-SIGN binds with high affinity to HIV envelope gp120
C. Facilitates CD4-mediated infection of dendritic cells
D. DC-SIGN allows efficient infection by aggregating virus on
surface of dendritic cells

5 Receptor that is abundantly expressed by macrophages facilitating
HIV infection is ?
A. Heparan sulfate proteoglycans – Syndecan
B. DC-SIGN
C, CD90
D. CD8+
6 Which of the following is the hallmark of HIV infection ?
A. Aberrant immune activation
B. Chronic, persistent infection
C. Profound immunodeficiency
D. All of the above

7 Which of the following is essential for efficient fusion & entry of
HIV-1 into its target cells ?
A. CD4 molecule
B. CCR5
C. CXCR4
D. All of the above

8 What proportion of individuals with primary HIV infection
experience the “acute HIV syndrome” ?
A. ~ 10 %
B. ~ 25 %
C. ~ 50 %
D. ~ 75 %

9 Acute HIV syndrome symptoms resemble which of the
following ?
A. Serum sickness like symptoms
B. Flu-like symptoms
C. Acute mononucleosis-like symptoms
D. Any of the above

10 Slope of HIV disease progression correlate with the set point of
the level of steady-state plasma viremia after how many months
of infection ?
A. ~ 3 months
B. ~ 6 months
C. ~ 12 months
D. ~ 18 months

11 Chronicity associated with persistent virus replication is seen in ?
A. HIV infection
B. HBV infection
C. HCV infection
D. All of the above

12 What is the mechanism of HIV infection to evade elimination by
the immune system ?
A. Selection of mutants that escape control by CTLs
B. High rate of replication & continual mutation of virus
C. Disappearance of clones of CD8+ CTLs
D. All of the above

13 Mechanism by which HIV evades neutralizing responses is ?
A. Hypervariability in primary sequence of the envelope
B. Extensive glycosylation of the envelope
C. Conformational masking of neutralizing epitopes
D. All of the above

14 Which of the following acts as a latent reservoir of HIV infected
cells ?
A. Lymphoid tissue
B. Peripheral blood
C. CNS
D. All of the above

15 Half-life of a circulating HIV virion is ?
A. ~ 30 – 60 minutes
B. ~ 60 – 90 minutes
C. ~ 90 – 120 minutes
D. ~ 120 – 180 minutes

16 What quantity of HIV virions are produced and cleared from the
circulation each day ?
A. ~ 1010 – 1011 virions
B. ~ 1011 – 1012 virions
C. ~ 1012 – 1013 virions
D. ~ 1013 – 1014 virions

17 Minimal duration of the HIV-1 replication cycle in vivo is ?
A. ~ 2 days
B. ~ 7 days
C. ~ 14 days
D. ~ 21 days

18 With ARV therapy, decrease in virus replication occurs in ?
A. Spleen
B. Lymph nodes
C. Peripheral blood
D. All of the above

19 CDC case definition of AIDS includes all HIV-infected individuals
with CD4+ T cell counts ?
A. < 200 / μL
B. < 250 / μL
C. < 300 / μL
D. < 350 / μL

20 Median time from primary HIV infection to development of AIDS
in untreated patients in developed world is ?
A. ~ 3 years
B. ~ 5 years
C. ~ 10 years
D. ~ 15 years

21 Individuals are considered to be long-term survivors if they remain
alive for how many years after initial infection ?
A. 5
B. 10
C. 15
D. 20

22 Which of the following is not a characteristic feature of long-term
nonprogressor ?
A. Infected with HIV for a long period (>10 years)
B. CD4+ T cell counts in the normal range
C. Received ARV therapy
D. Relatively low, but detectable levels of plasma viremia

23 Elite nonprogressors have HIV RNA levels of ?
A. < 50 copies per milliliter
B. < 100 copies per milliliter
C. < 150 copies per milliliter
D. < 200 copies per milliliter

24 Which of the following plays a direct role in restriction of virus
replication ?
A. HLA B*3701
B. HLA B*4701
C. HLA B*5701
D. HLA B*6701

25 Host genetic factors that delay the progression of HIV disease
include all except ?
A. Heterozygosity for CCR5-32 deletion
B. Heterozygosity for CCR2-64I mutation
C. Heterozygosity for SDF1-3’A mutation
D. Heterozygosity for RANTES-28G mutation

HIV / AIDS

[MCQ] HIV / AIDS- Part 4

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HIV / AIDS- Part 4

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