Viral sexually transmitted infections I Flashcards

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1
Q

What is the major nucleocapsid protein for HIV?

A

p24

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2
Q

What is the major matrix protein for HIV?

A

p17

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3
Q

What is the HIV attachment protein?

A

gp120

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4
Q

What is the HIV fusion protein?

A

gp41

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5
Q

What is the genome for HIV?

A

+ssRNA

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6
Q

Is HIV enveloped or non-enveloped?

A

Enveloped

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7
Q

HIV belongs to what virus family?

A

Retroviridae

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8
Q

What is required for maturation of HIV virions?

A

Extracellular protease-mediated cleavage of polypeptide

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9
Q

Where does gp120 bind during HIV infection?

A

CD4

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10
Q

Conformational change in gp120 allows binding to what coreceptors?

A

CCR5 and CXCR4

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11
Q

What is required for HIV entry into the cell?

A

Binding of coreceptor

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12
Q

R5 tropic HIV viruses infect what cell types best?

A

Monocytes / macrophages, microglia

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13
Q

What percentage of patients transfer from R5 to X4 viruses during HIV infection?

A

40%

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14
Q

Deletion in what coreceptor gene inactivates binding to gp120?

A

CCR5 delta-32 gene

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15
Q

What mediates the fusion between viral envelope and plasma membrane?

A

gp41

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16
Q

What kind of genome copy is made by reverse transcriptase?

A

Linear dsDNA copy of HIV RNA genome

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17
Q

What is the HIV provirus?

A

When viral DNA is incorporated into host genome (permanent)

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18
Q

How do HIV virions exit the cell?

A

Budding through plasma membrane at lipid rafts

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19
Q

Viral proteases cleave what polyproteins during virion maturation?

A

Gag and gag-pol

20
Q

What is required for infectivity of the HIV virion?

A

Protease cleavage

21
Q

Is HIV infection more efficient male-to-female or female-to-male?

A

Male-to-female

22
Q

What is the overall HIV transmission risk for mother-to-child transmission?

A

25%

23
Q

What is the HIV transmission risk for mother-to-child transmission AT BIRTH?

A

50-65%

24
Q

What is the risk of HIV transmission risk for needle stick?

A

0.3%

25
Q

What is the risk of HIV transmission from mucous membrane contact?

A

0.09%

26
Q

What can be measured in blood during the acute phase of HIV infection?

A

p24 capsid and viral genome

27
Q

When does chronic lymphadenopathy occur during HIV infection?

A

After viral replication goes down and anti-HIV antibodies (gp120) start going up

28
Q

When does acute HIV infection occur?

A

3-6 weeks following infection

29
Q

What are some of the ways in which HIV escapes the immune system?

A
  1. Antigenic drift of gp120
  2. Inactivation of key immune response elements
  3. Cell to cell fusion
30
Q

What is the median time of clinical latency in untreated patients?

A

10 years

31
Q

What is the HIV set point?

A

Predicts progression rate to AIDS in untreated patients

32
Q

What causes oral hairy leukoplakia?

A

Epstein Barr virus

33
Q

In order of diagnostic detectability, what HIV antigens are present in blood first?

A
  1. RNA
  2. p24
  3. HIV antibody
34
Q

What is the order of testing for HIV?

A
  1. HIV 1/2 antigen/Ab combination immunoassay
  2. HIV 1/2 Ab differentiation immunoassay
  3. HIV-1 PCR
35
Q

What does the HIV 1/2 antigen / Ab combination assay look for?

A

Anti-p24 antibody and viral antigen

36
Q

What test is performed if the antigen / Ab combination assay is positive?

A

Antibody differentiation immunoassay

37
Q

What are the contraindications for HIV entry inhibitors?

A
  1. Not recommended for initiation of treatment in newly diagnosed patients
  2. Generally reserved for people who have been on antiretroviral therapy for a while
38
Q

What are the two HIV entry inhibitor types?

A
  1. Chemokine coreceptor antagonists

2. Fusion inhibitors

39
Q

What do the chemokine receptor antagonists do?

A

Bind to coreceptor and prevent interaction with gp120

40
Q

What do the fusion inhibitors do?

A

Bind to gp41 and prevent conformational change needed for fusion of viral envelope with cellular plasma membrane

41
Q

What are the two types of reverse transcriptase inhibitors?

A
  1. Nucleoside inhibitors (NRTIs)

2. Nonnucleoside inhibitors (NNRTIs)

42
Q

What do the nucleoside inhibitors do? (NRTIs)

A

Incorporated into growing DNA chain during provirus synthesis - cause chain termination

43
Q

What do the nonnucleoside inhibitors do? (NNRTIs)

A

Bind to reverse transcriptase and inhibit its activity

44
Q

What do integrase inhibitors do?

A

Block integration of DNA copy of viral genome into cellular genome

45
Q

What do the protease inhibitors do?

A

Bind to active site and inhibit protease activity

46
Q

What is the standard of care for ARV therapy?

A
  1. Combinations of at least three drugs
  2. 1 NNRTI + 2 NRTIs
  3. 1 PI + 2 NRTIs
  4. 1 II + 2 NRTIs
  5. Note - 2 NRTIs always used