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MIIM30014 Virology > HIV, Retroviruses, Lentiviruses (18,30) > Flashcards

HIV, Retroviruses, Lentiviruses (18,30) Flashcards

1
Q

What is NOT a challenge in developing an AIDS vaccine?

a. There is a lack of knowledge on which antigens are needed for protection
b. There is a need for B cell approach vaccines as they are more successful than T cell approach vaccines
c. There is no immunological correlate of protection
d. Candidates need to elicit broadly neutralising antibodies to HIV as well as control HIV infection

A

b. There is a need for B cell approach vaccines as they are more successful than T cell approach vaccines

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2
Q

What is correct about Merck’s vaccine?

a. It elicited a robust neutralising antibody response in male Thai participants
b. It contained canary pox and gp120
c. It did not prevent HIV in subjects with pre-existing adeno5 antibodies
d. It had an efficacy of 31% against HIV subtype E

A

c. It did not prevent HIV in subjects with pre-existing adeno5 antibodies

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3
Q

What is INcorrect about the Sanofi study (RV144)?

a. The study demonstrated that HIV elicits cell mediated responses as opposed to neutralising antibody responses
b. It showed that vaccines would be most effective when delivered early and in low risk individuals
c. There was no difference in the amount of HIV infections recorded in the placebo group and vaccine group
d. It showed that protection is possible but boosting may be important

A

c. There was no difference in the amount of HIV infections recorded in the placebo group and vaccine group

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4
Q

What does 90-90-90 refer to?

a. The UNAIDS target of having 90% diagnosed, 90% on treatment and 90% virally suppressed
b. That 90% of retroviruses mutate 90% of their genome in 90% of the world’s population most susceptible to HIV infection
c. The UNAIDS target of eradicating AIDS in 90% of the world’s population
d. The WHO target of having 90% of AIDS suffers on HAART treatment by 2090

A

a. The UNAIDS target of having 90% diagnosed, 90% on treatment and 90% virally suppressed

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5
Q

What must be carried out to eliminate or silence HIV infected cells?

a. The viral genome must not be epigenetically modified
b. A HIV RNA assay must reveal that there is an undetectable viral load
c. Vaccines will only work against ‘silent’ HIV DNA
d. The latent infection must first be activated (e.g. HDACi)

A

d. The latent infection must first be activated (e.g. HDACi)

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6
Q

• Monkeys can be protected by SIV by immunisation with a live attenuated vaccine.

A

T

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7
Q

• The Sanofi study showed that AIDS vaccines will be most successful if based on neutralising antibody responses as opposed to cell mediated immunity.

A

F

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8
Q

• Late HAART era patients still have a 10year shorter life expectancy than those without HIV.

A

T

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9
Q

• Current HAART treatment often leads to death from AIDS as CD4+ T cells cannot be saved from depletion.

A

F

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10
Q

• When HAART is stopped, the amount of HIV RNA plummets rapidly.

A

F (RNA increases, rebound)

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11
Q

• HIV DNA in infected cells is always detectable.

A

T

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12
Q

Which statement about HIV prevalence in 2012 is INcorrect?

a. About 35.3 million people were infected
b. 2.3 million new infections arose
c. 1.6 million people died
d. 25 million infected people resided in Latin America

A

d. 25 million infected people resided in Latin America

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13
Q

What is cause of 70% of HIV cases acquired in Australia?

a. Injecting drug use
b. Male homosexual contact
c. Heterosexual contact
d. Undetermined causes

A

b. Male homosexual contact

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14
Q

What is cause of 80% of HIV cases acquired throughout the world?

a. Injecting drug use
b. Male homosexual contact
c. Heterosexual contact
d. Undetermined causes

A

c. Heterosexual contact

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15
Q

What does not influence a heterosexually transmitted HIV epidemic?

a. Social factors like large sexual networks
b. Behavioural factors like condom use
c. Social factors like high viral loads
d. Biological factors like low rates of circumcision

A

c. Social factors like high viral loads

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16
Q

What is a feature of HIV as a lentivirus?

a. It is enveloped and has helical symmetry
b. It has a diploid linear 9.2kb +ssRNA genome
c. HIV1 is the only human virus
d. The disease progresses rapidly

A

b. It has a diploid linear 9.2kb +ssRNA genome

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17
Q

What is a feature of the HIV-1 genome?

a. Pol encodes enzymes like RT, IN and PR
b. Env encodes structural proteins such as MA, CA and NC
c. Gag encodes envelope proteins SU and TM
d. Tat and Rev are spliced from the gag-pol polyprotein

A

a. Pol encodes enzymes like RT, IN and PR

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18
Q

What is correct about reverse transcription?

a. It cannot be targeted by antiviral drugs
b. The process has a low error rate
c. It leads to the formation of LTRs in viral cDNA
d. It requires host cell integrase and reverse transcriptase

A

c. It leads to the formation of LTRs in viral cDNA

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19
Q

What is a feature of HIV integration?

a. HIV cDNA integrates at OriP in host DNA
b. Integration cannot occur in terminally differentiated cells
c. Viral integrase is resistant to antiviral drugs
d. The 5’ LTR of the provirus acts as the HIV gene promoter

A

d. The 5’ LTR of the provirus acts as the HIV gene promoter

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20
Q

What is NOT a feature of the LTRs in the HIV provirus?

a. U5 at the 5’ end contains a polyadenylation signal
b. U3 at the 5’ end contains enhancer sequences and transcription start signals
c. NfKb is produced by activated T cells and can bind to the 5’ LTR
d. The 5’ LTR contains a cap site between U3 and R

A

a. U5 at the 5’ end contains a polyadenylation signal

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21
Q

What acts as the HIV gene promoter following integration into host DNA?

a. The 3’ LTR
b. Gag-pol sequence
c. The 5’ LTR
d. The Rev responsive RNA element

A

c. The 5’ LTR

22
Q

What is a feature Tat?

a. It binds to RREs on the 4kb and 9kb HIV RNA transcripts and exports them to the cytoplasm
b. It regulates structural gene expression
c. It represses transcriptional to initiate HIV latency
d. It binds 5’ TAR and activates CDK9 which phosphorylates and activates RNApolII

A

d. It binds 5’ TAR and activates CDK9 which phosphorylates and activates RNApolII

23
Q

Which statement about HIV accessory proteins is correct?

a. Vpu promotes infectivity by blocking cell defences and targeting ssCDNA
b. Nef down modulates MHC1 and Cd4
c. Vpr regulates particle release and Env processing and the degradation of MHC1 and CD4
d. Vif aids the nuclear import of cDNA and is involved in cell growth arrest

A

b. Nef down modulates MHC1 and Cd4

a. Vpu promotes infectivity by blocking cell defences and targeting ssCDNA (Vif)
c. Vpr regulates particle release and Env processing and the degradation of MHC1 and CD4 (Vpu)
d. Vif aids the nuclear import of cDNA and is involved in cell growth arrest (Vpr)

24
Q

What is a feature of the CCR5 co recptor?

a. Highly pathogenic, used late in infection, macrophage tropism
b. Naturally binds SDF1, T cell tropism, moderate pathogenicity
c. No syncytium, used early in infection, macrophage tropism
d. Moderate pathogenicity, induces syncytium, t cell tropism

A

c. No syncytium, used early in infection, macrophage tropism

25
Q

What is not a phase of untreated HIV infection?

a. Primary infection
b. Asymptomatic infection
c. Secondary infection
d. Symptomatic infection

A

c. Secondary infection

26
Q

What occurs during the primary infection of HIV?

a. There is an increase in blood and body CD4 T cells
b. There is a massive loss of memory T cells in the GALT
c. About 40% of mucosal T cells are killed
d. HIV levels rise due to the abundance of CD4

A

b. There is a massive loss of memory T cells in the GALT

27
Q

What can be detected following the sero-conversion window seen in HIV1 infection?

a. A HIV-1 EIA can be used after 5 days
b. A p24 antigen EIA can be used after 28 days
c. vRNA PCR can be used after 50 days
d. A HIV1/HIV2 EIA can be used after 75 days

A

b. A p24 antigen EIA can be used after 28 days

28
Q

What would NOT be used by HIV1 to avoid the immune response?

a. Sequence variation achieved through the low error rate of reverse transcription
b. Down-regulation of MHCI molecules
c. Variability in env V regions to escape antibody
d. Replication in privileged sites like the brain

A

a. Sequence variation achieved through the low error rate of reverse transcription

29
Q

What is NOT a way that HIV can cause T cell depletion?

a. By directly destroying infected cells
b. By damaging the GALT, leading to the release of microbial products and an inflammatory response
c. Indirectly destroying uninfected cells by down-regulating CD4 and CD8 T cell activation
d. Chronic immune activation of T lymphocytes

A

c. Indirectly destroying uninfected cells by down-regulating CD4 and CD8 T cell activation

30
Q

• HIV has caused 42.5 million deaths and 75,800,000 people have been infected.

A

T

31
Q

• HIV is more prevalent in Australia than other blood borne virus infections such as hepatitis B and C.

A

F

32
Q

• There is a high degree of variability for gag and env proteins due to the high error rate during reverse transcription.

A

T

33
Q

• HIV accessory proteins are critical in in vitro replication and in vivo pathogenesis.

A

F

34
Q

• Dendritic cells do not display CXCR4 receptors.

A

T

35
Q

• A Quasi steady state exists when viral production = viral clearance and this is known as the virological set point.

A

T

36
Q

What is a feature of Rev?

a. It activates HIV transcription elongation
b. It binds to RREs on the 4kb and 9kb HIV RNA transcripts and exports them to the cytoplasm
c. It binds and activates CDK9 in order to initiate splicing of late HIV RNA transcripts
d. It is expressed from the 9kb un-spliced HIV RNA transcript

A

b. It binds to RREs on the 4kb and 9kb HIV RNA transcripts and exports them to the cytoplasm

37
Q

What is not a host factor that determines HIV disease progression?

a. Having a CCR5 mutation
b. Having a high titre of neutralising antibody
c. Down regulation of HIV-1 specific CD8+ T cells
d. HLA type

A

c. Down regulation of HIV-1 specific CD8+ T cells

38
Q

What is not a reservoir for HIV?

a. Proliferating B cells
b. Macrophages in lymph nodes
c. The brain
d. LN germinal centres, trapped on follicular DCs

A

a. Proliferating B cells

39
Q

What is a feature of HIV latency in CD4+ T cells?

a. It is common
b. It is established at the level of translation
c. Latent HIV is successfully treated with HAART therapy
d. The latent provirus sequence doesn’t evolve

A

d. The latent provirus sequence doesn’t evolve

40
Q

What is true about the efficacy of biomedical interventions against HIV?

a. The prime boost HIV vaccine is 90% effective
b. Circumcision is 60% effective
c. Immediate ART for positive partners is only 5% effective
d. Tenofovir gel is 10% effective

A

b. Circumcision is 60% effective

41
Q

• AIDS can lead to the reactivation of EMV or CMV.

A

T

42
Q

• HIV is only active when patients are symptomatic.

A

F

43
Q

• HIV can survive in quiescent T cells from months to years.

A

T

44
Q

HIV is difficult to cure due to the nature of the host cells it resides in.

A

T

45
Q

Cells could become resistant to HIV by modifying surface proteins. (e.g. CCR5 - )

A

T

46
Q

Knocking out CCXR4 successfully prevents the escalation of HIV infection.

A

F (it is a critical chemokine receptor)

47
Q

Which is one of the main challenges of a current AIDS vaccine?

a. Control HIV infection as well as live attenuated SIV
b. Elicit specific antibody responses to single HIV strains
c. Implementing HDAC inhibitors together with IFN
d. Duplicating the gp120 based molecule used in Vaxgen

A

a. Control HIV infection as well as live attenuated SIV

48
Q

The Sanofi vaccine has showed the most promise with an efficacy of 90%.

A

F (31%)

49
Q

What is INCORRECT about the “shock and Kill” approach against HIV?

a. It aims to make the latent virus visible to the immune system
b. Targeting epigenetic modifiers is inefficient
c. HDAC inhibitors could be used as the HIV provirus is silenced by methylation
d. Methods involves PKC activators, T cell activators, DNMT inhibition and HMT inhibition

A

b. Targeting epigenetic modifiers is inefficient

50
Q

Reverse transcriptase is often targeted by HIV antivirals. Which of the following drugs targets the enzyme itself (and not the process carried out by the enzyme) ?

a. AZT
b. NNRTI
c. Raltegravir
d. NRTI

A

b. NNRTI

AZT and NRTI’s are nucleoside analouges that interfere with replication by RT

MIIM30014 Virology (23 decks)

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