Lecture 5- Retroviruses, AIDS, Tumor Viruses Flashcards

1
Q

HIV appears to have evolved from… and spread through the rest of the world through an increasingly mobile population and aberrant sexual behaviors

A

simian virus in africa

SIV–>HIV2–>HIV1 ~1930s

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2
Q

A unique feature of retroviruses is that they have an… even though they are an RNA virus

A

DNA intermediate

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3
Q

Many retroviruses are… but other have significant pathogenicity causing disease and cancer

A

benign

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4
Q

Retroviruses are… in vertebraes

A

ubiquitous

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5
Q

Spumaviruses do not cause… and they make … structures inside cell

A

human disease

“foamy”

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6
Q

2 subfamilies of retroviridae

A

orthoretroviridae

spumaviridae

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7
Q

The genome of retroviridae is…. and it is also … which is unique

A

(+)ssRNA

diploid (has 2 identical copies of its genome in the cell)

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8
Q

Are retroviridae viruses enveloped?

A

yes

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9
Q

What proteins do retroviridae viruses have?

A
  1. reverse transcriptase unique
  2. integrase
  3. protease
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10
Q

Historically, retroviruses were characterized by … and…

A

nucelocapsid structure and location in the particle

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11
Q

Retroviruses are now classified as either… or…

A

simple or complex

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12
Q

Simple retroviruses only encode for…. and complex includes others besides these

A

Gag, Pro, Pol, Env genes

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13
Q

Retroviruses are able to execute… at the cellular surface and do not require…

A
  • membrane fusion

- receptor mediated endocytosis

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14
Q

The main 2 steps in the replication cycle of a retrovirus is…. which is when… is made into… and then…. which is when the virus dsDNA integrates into host making provirus

A
  • reverse transcription

- ssRNA–>dsDNA

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15
Q

… is a defining feature of retroviruses and it initiates once nucleocapsid is in…
Need higher levels of…
Low levels of… prevent reverse transcription

A
  • cytoplasm

- NTPs

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16
Q

Reverse transcription is …. between genome copies so it is … when copies are identical and there are many different … when different genomes are in the virion

A
  • promiscuous
  • silent
  • recombinations
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17
Q

Integration of virus DNA is…

A

permanent

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18
Q

If integration is into the germ-line then provirus is… and is called…

A
  • inherited

- endogenous

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19
Q

Integration may disrupt host genes causing diseases such as

A

cancer

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20
Q

Integration identified oncogenes (4)

A
  1. transcription factors
  2. secreted growth factors
  3. growth factor receptors
  4. cell signal transduction pathways
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21
Q

In retrovirus replication, it is commong to have … viruses made during replication. These are viruses that are missing at least one of gag, pol or env

A

defective

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22
Q

Defective retroviruses require… to make progeny

A

complementary infection

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23
Q

Most retroviruses infections are… and are usually not…

They have little impact to … and…

A
  • benign
  • cytopathic
  • replication
  • physiology
24
Q

Chronic infections of retroviruses exert… demand on cell and host resources

A

small

25
Q

Retroviruses can cause … and elicit immune response, but host animals can live normal lives for many months or years

A

viremia

26
Q

Retroviruses are …. eliminated by the host response

A

nerver

27
Q

There are 3 categories of retroviruses that can cause significant disease:

A
  1. slow retroviruses
  2. cytopathic retroviruses
  3. acute transforming viruses
28
Q

Retroviruses that carry cytopathic genes are the…. and they cause tissue damage directly

A

minority

29
Q

…retroviruses have an effect that is like high level mutagenesis and eventually results in tumorigenesis

A

-slow

30
Q

…. viruses induce rapid tumor formation and they carry host genes ( mitogenic or antiapoptotic) and these are usually replication defective because host gene replaces an essential gene

A

acute transforming

31
Q

Human T-cell leukemia virus (HTLV) has 4 distinct types, which one is most often associated with humans?

A

HLTV-1

32
Q

HTLV is a… and it was first isolated in patient with cutaneous T-cell lymphoma in the late 1970s.

A

deltaretrovirus

33
Q

HTLV-1 transmission is usually…. to…

A

person to person

34
Q

HTLV-1 can be transmitted person to person by… (4)

A

breastfeeding
sharing needles
blood transfusions
sex (less efficient)

35
Q

An HTLV-1 disease is….. which follows mucosal exposure and occurs in 2-4% of cases and its latent period is 30-50 years and it infects memory T-cells

A

Adult T-cell Lymphoma/Leukemia (ATLL)

36
Q

Another HTLV-1 disease is…. which occurs in 1-2% of cases, this follows transfusions and it happens when infected T-cells enter CNS, activate astrocytes and microglial cells and recruit inflammatory cells causing further damage

A

Associated Myelopathy/Tropical Spastic Paraparesis (HAM/TSP)

37
Q

HAM/TSP symptoms typically have an onset of …. after infection. It starts with… and then progresses to lower back pain, leg weakness or stiffness in hips or knees. Men suffer impotence or erectile dysfunction

A
  • 3 years

- bladder control issues

38
Q

2 preventative measures for HTLV-1

A
  • dont breastfeed

- increased screening for blood products

39
Q

Treatment for ATLL (from HTLV-1) …

A

treat the leukemia with chemotherapy regardless of HTLV infection

40
Q

Treatment for HAM/TSP (from HTLV-1)

A

corticosteroids

41
Q

There are… main types of HIV and they are considered ….viruses. HIV was identified in 1984 and due to immune deficiency occuring in previously healthy gay men

A

2

lentiviruses

42
Q

HIV had the biggest impact in…

A

Sub-saharan africa

43
Q

… showed a decrease in AIDS incidence which targets reverse transcriptase. This drug helps with mother- child tansmission

A

AZT

44
Q

HIV transmission happens 3 different ways

A
  1. sexual
  2. parenteral- transfusion or needle sharing
  3. mother to infant
45
Q

What is the latent period for AIDS?

A

6 months to 25 years

46
Q

HIV targets….

A

memory T-cells (CD4+)

47
Q

Infection of HIV begins with ….

A

virus containing blood or body fluid to a mucosal surface or blood

48
Q

The initial acute infection of HIV is usually…. after infection

A

2 weeks

49
Q

What symptoms are indicative of HIV disease

A

mucocutaneous ulceration and weight loss

50
Q

…. seeded as a result of acute infection (reservoir)

A

Gut Associated Lymphoid Tissue (GALT)

51
Q

HIV disease causes … infections to increase

A

opportunistic

52
Q

Prevention for HIV

A
  • sexual behavior and protection

- blood screening

53
Q

Is there a vaccine or antivirals for HIV?

A

vaccine- no

antivirals-yes

54
Q

Retroviruses are an…. particle and are the only ones that are ….
Their genome is…

A

enveloped
diploid
(+)ssRNA

55
Q

The 2 unique features of retroviruses replication cycle are…

A
  1. reverse transcription

2. integration into host DNA