Quantification of Viruses Flashcards
What is virus quantification?
Counts the number of viruses in a specific volume to determine virus concentration
What is the virus titer?
- Lowest concentration of virus that still infects cells
2. The number of infectious units p/ml of sample
What are the two types of viral quantification tests?
- Biological
2. Physical
What are the 5 types of physical quantification tests?
- Viral Particle counts
- Hemagglutination (Ag conc.)
- Immunological assays, like ELISA
- Quantitative PCR assays
- Flow cytometry
What are two ways to directly count viral particles in solution?
- Direct particle count by TEM
2. Virus counter 2100
What does single radial immunodiffusion (SRID) assess?
Assessment based on antigen concentraion
What does qPCR assess?
Gene expression
What are 3 types of biological tests?
- Plaque assays
- Pock assays
- Various endpoint titration methods
What is a monolayer plaque assay?
A plaque, circular zone of necrotic cells, surrounded by viable cells in a monolayer
What does the PFU measure?
Measures number of virus particles capable of forming plaques per unit volume
What are the units for a monolayer plaque assay?
Plaque-forming units/ml (PFU)
What are the units for a pock assay?
Pock-forming units/ml
What is a pock assay?
Necrotic area on chorioallantoic membrane (CAM) of embryonated egg
What is a transformation assay?
Quantitative determination of titers of oncogenic viruses
What are the units for transformation assay?
Focus-forming units/ml
