Retrovirus Oncogenesis Flashcards
DNA viruses that cause cancer (5)
- Herpes
- Hepadna
- Adeno
- Papova
- Pox
RNA viruses that cause cancer (2)
- Flavi
2. Retro
Whats an oncogene
Any genetic element that causes cancer
What is a c-oncogene
A cellular (host) oncogene
Involved in regulation of cell growth, division, differentiation
Activated via:
- Insertional mutagenesis
- Transposition
- Gene amplification
- Mutation
What is a v-oncogene
Viral oncogene
Usually code only for exons
Under control of LTRs
Mutations of LTRs can cause what
Uncontrollable amplification
What is replication competent
Virus can replicate entirely by itself
What is replication defective
Virus requires interaction with another virus (helper virus) to complete infectious cycle
Are retroviruses replication competent or defective? Which cause cancer
Can be either - both cause cancer!
How are replication competent viruses oncogenic?
Cis-activating
Provirus inserted either on c-onc (knocking it out) or near it (upstream - causing upregulation via LTR)
How are replication defective viruses oncogeneic
Transducing
Which has shorter tumor latency period (transducing or cis-activating)
Transducing
Which has a higher efficacy of tumor formation (transducing or cis-activating)
Transducing
Can cis-activating transform cultured cells
No
What does cellular and humoral immunity do to virus
Cellular: clears virus
Humoral: protects against re-infection
List some ways the immune system can enhance viral damage
- Increased secondary response to killer T-cells
- ADCC or complement mediated cell lysis
- Binding virus-Ab complexes to Fc receptors —> more cells involved
- Immune complex depositions in eye, brain, etc
IgG is dominant maternal antibody in
Cows, horses
IgA is dominant maternal antibody in
Dogs, pigs
What is translocation cutoff time
Time to absorb maternal antibodies (usually around 2 days)
List reasons failure of antibody transfer
- Premature/weak
- Delay to suckle
- Death of dam
- Low colostrum
etc etc
What is most common immunodeficinecy disease in domestic animals
Failure of transfer
Why is vaccinating too early dangerous
Neonate may have maternal antibodies that attack vaccine, reducing titer
Why are boosters important
If you vaccinated too early, boosters will boost immune response to titer
Why is vaccinating too late dangerous
Maternal antibodies will drop below protective levels and animal will be susceptible to infection
What is window of susceptibility
Maternal antibody level that kills vaccine is below the minumum level needed for protection! When you vaccinate in this window, animal is not protected adequately
