Cultivation of Viruses
Dr. Emad AbdElhameed Morad
Lecturer of Medical Microbiology and Immunology
Viruses are obligate intracellular organisms.
So, they must be cultivated on living cells.
So, viruses could be cultivated on either:
Cell culture monolayer is the most commonly used system for
isolation of viruses.
Cell culture has three types:
1) Primary cell line:
Prepared for example from monkey kidney.
These cells can divide for 4-6 passages then die.
2) Human diploid cell line:
Prepared from human embryo fibroblasts.
These cells can divide for 50 passages then die.
3) Continuous cell line:
Prepared from tumor cells.
Example, HeLa cell line derived from carcinoma of the cervix.
These cells can divide indefinitely.
Detection of viral growth in tissue culture
Cytopathic effect (CPE)
They are changes which occur in the cells of the cell
1. Cell death.
2. Rounding and grape like cluster formation.
3. Syncytium formation (multinucleated giant cell
4. Cell transformation (the cells become malignant
Plaques are virally infected areas in the cell
Each plaque is produced by a single virus.
These plaques are seen by the naked eye as
unstained areas when using vital stains as
They are sites of assembly of the virus
components inside the infected cells.
May be intranuclear or intracytoplasmic.
Could be seen by the light microscope.
When red blood cells are added to the
infected cells, they will appear as rosettes.
This is useful in case of influenza and mumps
Some viruses do not produce CPE on cell
However, the growth of these viruses on cell
culture is detected by interference with the
formation of CPE by other viruses.