Virus Isolation

Cell cultures, eggs, and animals may be used for isolation. However eggs and animals are difficult to handle and most viral diagnostic laboratories depend on cell culture only. There are 3 types of cell cultures:

2.1. Types of cell cultures

1. Primary cells - e.g. Monkey Kidney. These are essentially normal cells obtained from freshly killed adult animals. These cells can only be passaged once or twice.
2. Semi-continuous cells - e.g. Human embryonic kidney and skin fibroblasts. These are cells taken from embryonic tissue, and may be passaged up to 50 times.
3. Continuous cells - e.g. HeLa, Vero, Hep2, LLC-MK2, BGM. These are immortalized cells i.e. tumour cell lines and may be passaged indefinitely.

Primary cell culture are widely acknowledged as the best cell culture systems available since they support the widest range of viruses. However, they are very expensive and it is often difficult to obtain a reliable supply. Continuous cells are the most easy to handle but the range of viruses supported is often limited.