Viral sexually transmitted infections I Flashcards Preview

Year 1 Microbiology > Viral sexually transmitted infections I > Flashcards

Flashcards in Viral sexually transmitted infections I Deck (46):
1

What is the major nucleocapsid protein for HIV?

p24

2

What is the major matrix protein for HIV?

p17

3

What is the HIV attachment protein?

gp120

4

What is the HIV fusion protein?

gp41

5

What is the genome for HIV?

+ssRNA

6

Is HIV enveloped or non-enveloped?

Enveloped

7

HIV belongs to what virus family?

Retroviridae

8

What is required for maturation of HIV virions?

Extracellular protease-mediated cleavage of polypeptide

9

Where does gp120 bind during HIV infection?

CD4

10

Conformational change in gp120 allows binding to what coreceptors?

CCR5 and CXCR4

11

What is required for HIV entry into the cell?

Binding of coreceptor

12

R5 tropic HIV viruses infect what cell types best?

Monocytes / macrophages, microglia

13

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

40%

14

Deletion in what coreceptor gene inactivates binding to gp120?

CCR5 delta-32 gene

15

What mediates the fusion between viral envelope and plasma membrane?

gp41

16

What kind of genome copy is made by reverse transcriptase?

Linear dsDNA copy of HIV RNA genome

17

What is the HIV provirus?

When viral DNA is incorporated into host genome (permanent)

18

How do HIV virions exit the cell?

Budding through plasma membrane at lipid rafts

19

Viral proteases cleave what polyproteins during virion maturation?

Gag and gag-pol

20

What is required for infectivity of the HIV virion?

Protease cleavage

21

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

Male-to-female

22

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

25%

23

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

50-65%

24

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

0.3%

25

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

0.09%

26

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

p24 capsid and viral genome

27

When does chronic lymphadenopathy occur during HIV infection?

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

28

When does acute HIV infection occur?

3-6 weeks following infection

29

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

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

30

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

10 years

31

What is the HIV set point?

Predicts progression rate to AIDS in untreated patients

32

What causes oral hairy leukoplakia?

Epstein Barr virus

33

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

1. RNA 2. p24 3. HIV antibody

34

What is the order of testing for HIV?

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

35

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

Anti-p24 antibody and viral antigen

36

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

Antibody differentiation immunoassay

37

What are the contraindications for HIV entry inhibitors?

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

What are the two HIV entry inhibitor types?

1. Chemokine coreceptor antagonists 2. Fusion inhibitors

39

What do the chemokine receptor antagonists do?

Bind to coreceptor and prevent interaction with gp120

40

What do the fusion inhibitors do?

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

41

What are the two types of reverse transcriptase inhibitors?

1. Nucleoside inhibitors (NRTIs) 2. Nonnucleoside inhibitors (NNRTIs)

42

What do the nucleoside inhibitors do? (NRTIs)

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

43

What do the nonnucleoside inhibitors do? (NNRTIs)

Bind to reverse transcriptase and inhibit its activity

44

What do integrase inhibitors do?

Block integration of DNA copy of viral genome into cellular genome

45

What do the protease inhibitors do?

Bind to active site and inhibit protease activity

46

What is the standard of care for ARV therapy?

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