A cell line is a cell that has undergone mutation and series of genetic manipulations, and will not undergo apoptosis after a limited number of passages (sub-culturing). Apoptosis is defined as programmed cell death. It is a cell death that occurs by a biologically-controlled intracellular process that involves the fragmentation and cleavage of the host cells nucleic acid (particularly the DNA). When cells from the first culture (usually taken from the organism) are used to make subsequent cultures, a cell line is established. Immortal cell lines can replicate indefinitely due to manipulations of their genetic material and the maintenance and sustenance of optimum nutrient and environmental conditions. Cell lines are cells or cell cultures obtained after the first subculture of a primary cell culture.
This primary cell culture becomes known as a cell line or sub-clone after the first subculture has taken place. Cell lines derived from primary cultures usually have a limited life span. But as these cells are passaged, those cells with the highest growth capacity predominate. This will result in a degree of genotypic and phenotypic uniformity of the population of cells that will be produced. Such cells produced in this way are generally referred to as cell lines. Cell lines are obtained or sourced for research purposes in any of the following ways:
- Through primary culture
- Through Passaging or sub-culturing
- Through buying and borrowing either from already established cell collection centers such as the American Type Culture Collection (ATCC). Cell lines can also be sourced from research laboratories and institute in possession of cell lines. Cell lines obtained by borrowing are usually not too good because they can be contaminated by bacteria or mycoplasmas
Some established cell lines include: Chinese hamster ovary (CHO), HeLa cell lines, 3T3 cell lines and BHK21 cell lines. These established cell lines can be commercially obtained and used for cell culture experimentations.
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