Immunology 4 - HIV infection Flashcards

1
Q

Using which enzyme does HIV replicate inside cells?

A

Reverse Transcriptase

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2
Q

How many genes are inside the HIV genome?

A

9

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3
Q

What is the role of reverse transcriptase in HIV?

A

Converts RNA into DNA which can be incorporated into host cells’ genes

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4
Q

What are the two key glycoproteins encoded by the HIV virus?

A

gp120

gp41

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5
Q

Which cell of the immune system is particularly affected by HIV?

A

CD4+ T cells

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6
Q

Recall the receptor and co-receptors for HIV on CD4+ T cells

A

CD4 receptors

CCR5 CXCR4 coreceptors

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7
Q

In people who have natural immunity to HIV, what antibodies may be present in serum?

A

Anti-gp120 and anti-gp41 (Nt) antibodies

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8
Q

How does HIV infection affect CD8+ T cells?

A

Interferes with activation, as CD4+ T cell and antigen-presenting cell help are not present due to the virus

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9
Q

How does HIV infection affect monocytes and dendritic cells?

A

Not activated by CD4+ T cells and so cannot prime naive CD8+ T cells

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10
Q

How does HIV affect immunological memory?

A

CD4+ T cell memory is lost

CD8 memory cell not activated by antigen-presenting cell

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11
Q

Why is there so much variation/mutation in HIV infection?

A

HIV lacks same checking mechanisms in DNA transcription

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12
Q

Why is HIV mutation within the host problematic?

A

Escape from neutralising antibodies.

Escape from HIV-1-specific T cells.

Resistance and escape from antiretroviral drugs.

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13
Q

Recall the 7 steps of the HIV life cycle

A
  1. Attachment/Entry
  2. Reverse Transcription and DNA Synthesis
  3. Integration
  4. Viral Transcription
  5. Viral Protein Synthesis
  6. Assembly of Virus and Release of Virus
  7. Maturation
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14
Q

Which drugs are capable of inhibiting the action of reverse transcriptase in HIV infection?

A
  1. Nucleoside analogues

2. Non-nucleotide reverse transcriptases

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15
Q

Which class of HIV drugs can prevent integration of viral DNA?

A

Integrase inhibitors

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16
Q

Which HIV drugs can prevent modification of translated viral proteins?

A

Protease inhibitors

17
Q

What is the median time of infection with HIV to AIDS development?

A

8-10 years

18
Q

What does it mean if someone is an HIV exposed seronegative individual?

A

Partner of individual with HIV who remains uninfected

19
Q

What are the 3 major markers used to monitor HIV?

A

CD8
CD4
Plasma viral load

20
Q

What is long-term nonprogression of HIV?

A

Individual who is asymptomatic 10 years after infection

21
Q

How can HIV be detected?

A

anti-HIV antibodies (ELISA)

Viral load (PCR) - more sensitive

ELISA = screening

Western Blot = Confirmatory test

22
Q

How are CD4+ T cell levels measured in HIV infection?

A

Flow cytometry

23
Q

What are the two methods of testing for ARV resistance?

A

Phenotypic

Genotypic (involves directly sequencing the amplified genome)

24
Q

Which drugs make up a HAART regimen?

A

Three or more drugs + one or more binding agents

25
Q

When should HAART treatment be initiated?

A

Immediately

26
Q

Give 2 examples of NRTI HIV drugs

A

Zidovudine

Lamivudine

27
Q

Recall 2 examples of protease inhibitor HIV drugs

A

Tenofovir

Truvada

28
Q

What class of drug is raltegravir?

A

Integrase inhibitor

29
Q

Which drugs make up the HAART regimen initially?

A

2 NRTIs + PI

30
Q

What CD4 count defines AIDS?

A

<200 cells/ nanolitre

31
Q

Which drugs make up the atripla pill?

A

Emtricitabine + tenofavir + efavirenz

32
Q

Which ARV is best to use in pregnancy?

A

Zidovudine

33
Q

How can CD8+ T cells provide HIV entry into cells?

A

Producing chemokines MIP-1A, MIP-1b and RANTES