Flashcards in Viral sexually transmitted infections I Deck (46)
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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
