Adenovirus

Question 1

Outline adenovirus structure and replication.

Answer 1

Structure: non-enveloped 68-80 nm icosahedral
Replication:
1. Virus attachment to receptors on the host cell surface.
2. Internalization of the virus by endocytosis.
3. Low pH results in endosomal acidification and partial disassembly of the virion.
4. Virion released from endosome and trafficked to the nuclear pore complex where it releases viral DNA into the nucleus.
5. Early phase; transcription and subsequent translation of early genes to the regulatory early proteins.
6. Late phase; transcription and subsequent translation of late genes to the late structural proteins.
7. Assembly of progeny virion
8. Cell lysis resulting in release of mature virus.

Question 2

What are the functions of early genes and late genes?

Answer 2

Early genes: host and viral transcription control, and viral DNA replication.
Late genes: virion structure.

Question 3

Discuss the differences of Lytic, latent, oncogenic adenovirus infections.

Answer 3

Lytic:
- Entire replicative cycle.
- Epithelial cells.
- Results in cell death.
- Produces 10,000 to 1,000,000 viruses per cell only 1% to 5% are infectious.
Latent:
- Lymphoid cells (tonsillar infection).
- Small numbers of virus produced.
- Cell death outpaced by cell multiplication.
- Inapparent infection.
Oncogenic:
- Early steps of viral replication only.
- Viral DNA integrated into and replicated with in host cell DNA.
- No infectious virus produced.
- High oncogenic potential with low G + C viral DNA conntent.

Question 4

Discuss the clinical symptoms associated with Adenovirus respiratory infection, Pharyngoconjuctival fever, Keratoconjuctivitis, Cystitis, and Infantile diarrhea.

Answer 4

• Adenovirus respiratory infection: fulminant bronchiolitis, pneumonia, mild pharyngitis, cough, fever, sore throat, rhinorhea.
• Pharyngoconjuctival fever:
  conjunctivitis, pharyngitis, rhinitis, cervical adenitis, fever.
• Keratoconjuctivitis:
  keratitis begins as conjunctivitis resolves.
• Cystitis:
  blood in urine, dysuria, frequency.
• Infantile diarrhea:
  watery diarrhea, fever.

Question 5

What are the advantages of using adenovirus as a vector for gene delivery?

Answer 5

infects many different human cell types, dividing and non-dividing cells, non-integrating virus, high level of protein expression.