Observation for cytopathic effect: evidence of growth of
virus in cell culture is by the
detection
of cytopathic effect (CPE). Cytopathic effect is defined as degenerative
changes
caused by the growth of viruses in cell culture or virus-induced damage in cell
culture.
The following are examples of cytopathic effect which are usually observed by
microscopy:
1.
Cell lysis or cell disintegration
2.
Syncythial formation: formation of multinucleated giant cell due to cell
fusion. This is
found
with lentivirus, herpesviruses, paramyxoviruses
3.
Rounding up of cell or cellular transformation (change from spindle shape to
spherical
shape)
4.
Formation of intranuclear (adenovirus, herpesvirus, parvovirus) or
intracytoplasmic
(poxvirus,
rhabdovirus, reovirus) inclusion bodies.
Viruses can be
categorized into burster or creeper viruses based on the type of
CPE
produced.
Burster (lytic)
viruses: these induce cell lysis and cellular transformation in cell culture
Creeper viruses: these
induce formation of multinucleated giant cells.
Plaques: Macroscopic/gross observation of CPE on monolayer
cell by overlaying with
molten
agar. Plaques are foci of dead virus-infected cells which do not take up the
stain
(acridine
dye) when stained and so appear as clear spots in a stained monolayer.
Haemadsorption: adherence of erythrocytes to monolayer
cells because of the growth
of
haemagglutinating virus in the cells. Haemagglutinin is expressed on the cell
membrane
of cells in monolayer and this attracts and binds erythrocytes. Feline
panleukopaenia
virus haemagglutinate porcine erythrocyte while porcine parvovirus
haemagglutinate
chick, guinea pig, monkey, human and cat erythrocytes.
Immunofluorescence
Interference
Virus neutralization test
Haemagglutination inhibition test
0 Comments:
Post a Comment