L67

Question 1

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

Answer 1

dsDNA
- Nuclear replication
Naked + icosahedral

Question 2

What is the presentation of polyoma virus?

Answer 2

Usually nothing!

Only seen in IC pts

Question 3

Polyoma virus transmission

Answer 3

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

Question 4

What is the reading frame of polyoma virus vs HPV?

Answer 4

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

Question 5

How is polyoma virus released from host cells?

Answer 5

Lysis

Question 6

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

Answer 6

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

Question 7

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

Answer 7

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

Question 8

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

Answer 8

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

Question 9

How is HPV transmitted?

Answer 9

Direct contact of warts - hand to hand or sexual contact

Birth

Question 10

What are the 3 major regions of the HPV genome?

Answer 10

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

Question 11

What are 2 unique features about HPV?

Answer 11

1. Can cause cancer

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

Question 12

Explain HPV pathogenesis.

Answer 12

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

Question 13

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

Answer 13

Integration of HPV episome into host cell DNA

• Lose E2
• More direct upregulation of E6&7

Question 14

Describe how HPV can cause cancer.

Answer 14

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

Question 15

What types of cancer does HPV cause?

Answer 15

Cervical
Oral
Anal - increased in HIV+ gay men

Question 16

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

Answer 16

Recurrent respiratory papillomatosis

Question 17

Which strains of HPV are low risk?

Answer 17

6 & 11

Question 18

Which strains of HPV are high risk?

Answer 18

16 & 18

Question 19

What is CIN 1?

Answer 19

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

Question 20

What types of CIN are considered pre-cancerous lesions?

Answer 20

CIN 2 & 3

Question 21

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

Answer 21

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

Question 22

Gold standard of detecting HPV

Answer 22

Molecular DNA/RNA detection

1. PAP
2. Biopsy

Question 23

How does the vaccine work?

Answer 23

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