Retroviruses and HIV Flashcards

1
Q

PEP Regimen

A

Integrase Inhibitor + 2 NRTI’s given within 72 hours of infection

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2
Q

gp120

A

Surface envelope protein of HIV encoded on Env; Contains highly variable regions; Used for attachment

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3
Q

Technique to monitor HIV viral loads

A

RT-PCR

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4
Q

LTR

A

long term repeat; bind cellular and viral transcription factors (promoters and enhancers)

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5
Q

HIV Regulatory proteins

A

TAT, REV, and NEF

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6
Q

Mutation for HIV Resistance

A

CCR5 mutation; 10% of Caucasians are heterozygous, 1% are homozygous

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7
Q

Structural genes of HIV

A

Gag, Pol, and Env

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8
Q

Predictor of disease time course and progression to AIDS

A

viral load after acute infection

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9
Q

Nef

A

non-essential HIV protein that’s only required for disease progression; down-regulates CD4 and MHC Class I molecules

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10
Q

Defining feature of retroviruses

A

presence of Reverse Transcriptase

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11
Q

PrEP Regimen

A

Two NRTI’s taken daily

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12
Q

Properties of Oncoviruses

A

Can immortalize or transform cells because they contain growth-regulating oncogenes almost identical to genes involved in cellular growth

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13
Q

How is HTLV-1 transmitted

A

Sexually, through breastfeeding, and by IV drug use (US)

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14
Q

HIV Integrase Inhibitors

A

Inhibit HIV genome integration into host cell chromosome by reversibly inhibiting HIV integrase

Drugs have “tegr” in middle

Raltegravir

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15
Q

Unique features of Reverse Transcriptase

A

Protein dimer that: 1) Can act as DNA Polymerase while using either RNA or DNA as template 2) Can remove RNA strand from RNA:DNA duplex

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16
Q

HIV protein that down-regulates CD4 and MHC Class I molecules

A

Nef

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17
Q

HIV Antibodies appear when?

A

3-8 weeks after infection

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18
Q

Preferred HIV co-receptor for sexual transmission

A

CCR5

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19
Q

Genes in genome of Retrovirus

A

Gag, Pol, Env, and LTR

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20
Q

Tax and HBZ

A

genes on HTLV-1 that promote viral gene expression and host cell cycle by binding to LTR or other cellular growth factors

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21
Q

HIV protein that stabilizes viral mRNA containing RRE by preventing splicing

A

Rev

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22
Q

Tat

A

HIV protein that acts as positive regulator of transcription by binding to region in LTR and recruiting RNA Polymerase II

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23
Q

Provirus

A

Virus that has integrated into genome

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24
Q

Treatment for HTLV-1

A

ATLL: anti-cancer therapy

TSP: antiretrovirals

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25
Q

gp40

A

transmembrane envelope protein of HIV encoded on Env

26
Q

V3 Sequence

A

Can be used to predict whether HIV Strain will prefer CCR5 or CXCR4 as co-receptor

27
Q

Diagnosis of HIV

A

4th Generation Diagnostic Test detects Antibodies to HIV-1 and HIV-2 as well as the p24 Antigen (which allows this test to work during window period). Confirmatory test needed to distinguish HIV-1 vs HIV-2. Previous tests performed immunoassays which only detected antibodies

28
Q

Structure of Retroviruses

A

Enveloped, Icosahedral Viruses with two identical copies of Single Stranded Positive Sense RNA

29
Q

gene that encodes reverse transcriptase, protease, and integrase

A

pol

30
Q

gag

A

encodes the capsid and matrix proteins

31
Q

Purpose of Combination Therapy

A

Virus is unlikely to mutate and develop resistance to three different mechanisms at once

32
Q

HIV capsid protein and what gene it’s on

A

p24 Capsid encoded on Gag

33
Q

HIV Protease Inhibitors

A

Competitive inhibitors of HIV protease that prevents cleavage of Gag and Pol precursor peptides thus preventing viral maturation to infectious form

Drugs have -navir suffix

34
Q

Diseases caused by HTLV-1

A
  1. Adult T Cell Leukemia
  2. Tropical Spastic Paraparesis (myelopathy)
35
Q

HIV-1 vs HIV-2

A

HIV-2 is less virulent and less common

36
Q

When is LTR formed?

A

LTR’s are formed when a DNA copy is made from RNA by Reverse Transcriptase in order to allow integration into nucleus

37
Q

Rev

A

HIV protein that stabilizes viral mRNA containing RRE by preventing splicing

38
Q

env

A

gene that encodes surface and transmembrane proteins

39
Q

Where is HTLV-1 prevalent

A

Japan and Carribean

40
Q

Lentivirus family includes

A

HIV-1, HIV-2, and SIV

41
Q

Diagnosis criteria for AIDS

A

1) CD4 T Cell Count < 200 per uL 2) certain opportunistic infections

42
Q

Nucleoside/Nucleotide Reverse Transcriptase Inhibitors (NRTI’s)

A

Competitively inhibit nucleotide binding to reverse transcriptase and cause early termination; selectively inhibit HIV RT over host cell Polymerase.

Tenofovir is a nucleotide analog and does not require phosphorylation. Nucleoside analogs require phosphorylation before they are active

43
Q

Receptors for HIV

A

CD4 with co-receptor CCR5 or CXCR4

44
Q

Most important predictor of HIV disease stage

A

CD4 T Cell Count

45
Q

pol

A

encodes reverse transcriptase, protease, and integrase

46
Q

Important genes encoded on HTLV-1

A

tax and HBZ; HTLV-1 DOES NOT contain an oncogene.

These genes encourage expression of cellular growth factors and viral mRNA

47
Q

HIV viral enzymes and what gene they’re on

A

Protease, Reverse Transcriptase, and Integrase on Pol; Reverse Transcriptase and Integrase are packaged within the viron

48
Q

HIV Fusion Inhibitor (Enfuvirtide)

A

Blocks the fusion of gp41 on HIV envelope with host cell membrane

49
Q

Gene that encodes the capsid

A

gag

50
Q

Risk of HIV transmission from mother to fetus before ART vs after ART

A

30% vs < 2% ; women instructed not to breastfeed

51
Q

Importance of Variable Regions

A

Allow Quasi Species of HIV to form within host which can allow the virus to evade immune detection or become better at binding CD4

52
Q

HIV envelope proteins and what gene they’re on

A

gp120 and gp40 on Env

53
Q

Multilobulated lymphocytes known as “Flower Cells” are seen in what disease?

A

Adult T Cell Leukemia caused by HTLV-1

54
Q

bind cellular and viral transcription factors (promoters and enhancers)

A

LTR

55
Q

HIV Entry Inhibitors (Maraviroc)

A

Block gp120 from binding to CCR5 (chemokine receptor antagonist); ineffective against HIV strains that bind CXCR4

56
Q

Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTI’s)

A

Non-competitively bind to hydrophobic region of HIV Reverse Transcriptase Efavirenz, Nevirapine, Delavirdine

57
Q

ARV regimen for HIV+ Patient

A

Two different NRTI’s + one of the following: 1) Integrase Inhibitor 2) NNRTI 3) Protease Inhibitor

58
Q

Oncovirus Family includes what?

A

HTLV1

59
Q

HIV Accessory Genes

A

Vif, Vpr, and Vpu; these genes are involved in manipulating the host cell and promoting its survival

60
Q

gene that encodes surface and transmembrane proteins

A

env

61
Q

HIV protein that acts as positive regulator of transcription by binding to region in LTR

A

Tat