Virus-virus interaction Flashcards
1
Q
Examples of a virus’ environment
A
- Another virus
- Host cell
- Host organism
2
Q
When does virus-virus interaction occur?
A
- During multiplication
- Simultaneous infection of the same cell
- Usually between related viruses
3
Q
Give the types of virus-virus interaction
A
- Advantageous
- On NA level (recombination)
- On protein level
- Disadvantageous (Interference)
- Neutral (Virusexaltation)
4
Q
Whose best?
A
Luke’s best
Cian Ryan is gay
5
Q
Recombination
A
Exchange of genetic information
- New virus generation - inherited new properties
- At least 20-40 nucleotide homology between the viruses is needed
6
Q
Intramolecular recombination
A
- Derailing of the polymerase during replication
- Aujeszky’s disease virus: 70% transfer
- Sometimes between non-related viruses
- Also with RNA viruses
7
Q
Genetic reassortment
A
- Viruses with a segmented genome
- Exchange of segments during viral assembly
- Sudden, major antigenic changes
- Antigenic shift
8
Q
Reactivation
A
- Cross reactivation
- Attenuated vaccine strain + related virus
- Repair of the defected virulence-genes
- i.e herpesvirus
- Multiple reactivation
- Between two attenuated virus-strains
- Different defected genomic regions
- Mutual completion
9
Q
Two different live vaccines shouldn’t be used when?
A
Within a short time interval
10
Q
Complementation
A
- Between defective and competent (helper) viruses
- Exchange of enzymes (polymerase)
- Multiplication of the defected virus
- Heat sensitive-mutant + wild type virus
- Avirulent virus + inactivated virulent virus
- Dependovirus + adenovirus
- Multiplication of the defected virus
11
Q
Phenotype mixing
A
- Exchange of structural proteins
- Leukosis + sarcoma virus: Acquiring envelope proteins
- Transcapsidation
- Non-heritable
12
Q
Interference
A
One virus inhibits the multiplication of the other:
- Adsorption interference
- Autointerference
- Heterologous interference
13
Q
Adsorption interference
A
- Competition for the same cell-surface receptor
- Related viruses or
- After phenotype mixing or
- Different viruses but the same receptor
14
Q
Autointerference
A
- Complete and incomplete forms of the same virus
- Also at adsorption
- Incomplete virion:
- Shorter nucleic acid
- Higher mobility, polymerase affinity
- Competition for enzymes, ribosomes
- Defective interfering particles (DI)
- Large amounts of incomplete progeny viruses
- Self-limiting infections
15
Q
Heterologous interference
A
- Non-related viruses
- Vital suppressor protein production
