L67 Flashcards

1
Q

What is the genome and viral structure of polyomavirus & HPV?

A

dsDNA
- Nuclear replication
Naked + icosahedral

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2
Q

What is the presentation of polyoma virus?

A

Usually nothing!

Only seen in IC pts

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3
Q

Polyoma virus transmission

A

Respiratory
1ary inoculation of lungs
2ary inoculation of trophic organs

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4
Q

What is the reading frame of polyoma virus vs HPV?

A

Polyoma = open reading frame on BOTH strands
- Coded in counter vs clockwise fashion accordingly
HPV = reading frame on 1 strand only, therefore coded directionally

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5
Q

How is polyoma virus released from host cells?

A

Lysis

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6
Q

What are the 3 major parts of the polyoma virus genome?

A

Early = non-structural
- Large T antigen, inactivates p53 & Rb
Late = structural
Non-coding

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7
Q

What is the polyoma virus that infects the CNS? What disease does it cause?

A
JC virus
PML 
- Infects oligiodendrocytes 
- Demyelinating, white matter
- "Non-enhancing brain lesions"
- Gait, vision, speech changes
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8
Q

What is the polyoma virus that infects the kidneys? What diseases does it cause?

A

BK virus
Nephropathy
Ureteral stenosis
Hemorrhagic cystitis (more common in stem cell transplant pts)

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9
Q

How is HPV transmitted?

A

Direct contact of warts - hand to hand or sexual contact

Birth

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10
Q

What are the 3 major regions of the HPV genome?

A
Early = E1-7
- Cancer proteins
Late = structural proteins
- L1 = major capsid
- L2 = minor capsid
LCR region
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11
Q

What are 2 unique features about HPV?

A
  1. Can cause cancer

2. Associated with cells at specific stages of differentiation - actively dividing cells

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12
Q

Explain HPV pathogenesis.

A

Microtrauma
HPV + basal layer epithelium
Codes early genes = host cell growth –> wart
Replicate viral episome with HOST DNApol
Late genes on in terminally differentiated epithelial layers (top, keratinized)
Virus assembles in nucleus - sheds with dead upper layers

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13
Q

What event increases the likelihood of a carcinogenic strain of HPV?

A

Integration of HPV episome into host cell DNA

  • Lose E2
  • More direct upregulation of E6&7
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14
Q

Describe how HPV can cause cancer.

A
@ transition zones
Increased:
- E6: decreased p53 
- E7: degrade Rb
Net: loss of regulation of cell cycle, neoplasia
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15
Q

What types of cancer does HPV cause?

A

Cervical
Oral
Anal - increased in HIV+ gay men

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16
Q

What disease does HPV cause if newborns get it from the birth canal?

A

Recurrent respiratory papillomatosis

17
Q

Which strains of HPV are low risk?

A

6 & 11

18
Q

Which strains of HPV are high risk?

A

16 & 18

19
Q

What is CIN 1?

A

Cervical intra-epithelial neoplasia
Overgrowth due to 6 & 11
Lesions that are NOT considered cancer precursor

20
Q

What types of CIN are considered pre-cancerous lesions?

A

CIN 2 & 3

21
Q

What characteristic of an HPV infection is a good predictor of a carcinogenic strain?

A

Persistence = 2+ infections of the same strain in 6-12mo

22
Q

Gold standard of detecting HPV

A

Molecular DNA/RNA detection

  1. PAP
  2. Biopsy
23
Q

How does the vaccine work?

A

Recombinant
L1 subunit self assembles into BLPs to create Ab response 4x greater than natural Ab response to infection (which is generally ineffective)