Part 4: Methods Flashcards
- microscopic examination for viral inclusions
- less sensitive than culture
- helpful for viruses that are difficult to grow
Cytology/ Histology
- rarely used because it’s labor-intensive and expensive
- useful for virus that can be cultured
Electron Microscopy
- antiviral antibodies are used to stain viral antigens in specimen and cultures
Immunofluorescent Microscopy
- usually solid-phase and membrane Elisa are used
- the basic test consists of antibodies bonded to enzymes; the enzymes remain able to catalyze a reaction yielding a visible discernible end product while attached to antibodies
Enzyme Immunoassay (EIA)
- baby hamster kidney cell culture with B-galactosidase gene that is expressed when cells are infected with the virus
Enzyme Linked Virus Inducible System (ELVIS)
- different viruses grow on different cell lines
- growth takes about 1 – 28 days
- microscopically examined for cytopathic
effects (CPE) - confirmed with immunofluorescent stains
Conventional Cell Culture
cell rounding, clumping, vacuolation, granulation, giant multinucleate cell formation, cell fusion, syncytium formation, lysis, plaques (groups of killed cells), inclusion bodies.
cytopathic effects (CPE)
- derived from animals’ tissue slices
- tends to die after a few generations
Primary Cell Line
- derived from sub cultivation of primary cell line
- from human embryo can be maintained up to 100 generations
Diploid Cell Line
- derived from malignant tissue or transformed cells
- indefinite number of generations
Immortal Cells / Continuous Cell Line
- modified conventional culture
- detection in 1 – 2 days
* specimen is centrifuged onto a monolayer of cells
growing on coverslips
* coverslips are stained with viral specific
immunofluorescent conjugate - for viruses that are slow in producing CPE
Shell Vial Culture
- direct test
- latex beads are coated with antivirus antibodies - - rapid and cheaper
Latex Agglutination
- molecular method of detecting virus
- multiplication of viral structure for easier identification
Polymerase Chain Reaction (PCR)
- detects viruses in serum (Western Blottting)
- useful in evaluating immune status or diagnosing viral infections where culture is difficult and impossible
Serology
- results when a virus mistakenly infects a cell that does not permit viral replication
- no effect on host cell
Abortive Infection
- results to cell lysis and release of large
number of viruses
Cytolytic Infection
Persistent Infection
a.
b.
c.
Persistent Infection
a. Productive
b. Latent
c. Transforming
- with virus reproduction
- causes senescence
Productive
- no effect
Latent
RNA- _________ production, immortalization
DNA - _________ production, immortalization
Transforming
RNA- no virus production, immortalization
DNA - with virus production, immortalization
