VPB 321: Animal Biotechnology (2+1)

PRIMARY CELL CULTURE 

• A primary cell culture is established by inoculating cells taken directly from animal or human tissue into growth medium. The tissue is generally fragmented into small pieces and the execised fragments are treated with a proteolytic enzyme, Trypsin, which disaggregates the tissue into individual cells.
• Primary cell cultures retain most of the characteristics of the cells from which they originated and generally they are anchorage dependant. These cells exhibit a phenomenon called “ contact inhibition” which results in cells lining up in strongly oriented parallel strands. In any vessel these cells multiply until they reach a maximum density after which they stop growing further.With regard to chromosomal number, these type of cells usually retain their diploid karyotype.

Primary culture

• Freshly isolated cultures from mammalian systems are known as primary cultures until it is subcultured. At this stage they are usually heterogenous but still closely representative of the parent cell types and in the expression of tissue specific properties.
• After the first sub culture- or passage the primary culture becomes cell lines and may be propagated or subcultured several times. After several subcultures onto fresh media, the cell line will either die out or transform to become a continuous cell line.
• Such cell lines show many alterations from the primary cultures, including changes in
• Cytomorphology
• Increased growth rate
• Increase in chromosome variation
• Tumorigenicity
• In vitro transformation is primarily the acquisition of an infinite life span. Animal cells can be grown either in an unattached suspension culture or attached to a solid surface. They do not exhibit the property of contact inhibition and some are anchorage independent and could be established in suspension cultures. Cell lines show a great variation in karyotype. Continuous cell lines are usually aneuploid and often have a chromosome number between the diploid and tetraploid value.
• There are two types of cells
• Anchorage dependant cells: Cells attach to a solid surface Eg. Primary or normal diploid cells.
• Anchorage independent cells: Cells do not require any solid surface for their attachment. Suspension cultures: Eg. Hela, BHK 21 (Razi).
• Roller tubes and bottles are used for anchorage dependent cells.