Cells, removed from animal tissues or whole animals, will continue to grow, if supplied with nutrients and growth factors. This process is called cell culture. It occurs "in vitro" ("in glass") as opposed to "in vivo" ("in life"). The culture process alllows single cells to act as independent units much like any microorganism such as bacteria or fungi. The cells are capable of division by mitosis and the cell population can continue growth until limited by some parameter such as nutrient depletion.
Cultures normally contain cells of one type. The cells in the culture can be genetically identically (homogenous population) or may show some gentic variation (heterogenous population). A homogenous population of cells derived from a single parental cell is called a clone. Therefore all cells within a clonal population are genetically identical. Cell culture is a widely used technique.1
Cell culture has become in integral part of the daily routine of most biological laboratories. Many genetic tests, chemo-resistance testing for chemotherapy, and the study of deregulated cell proliferation in cancer, cannot be performed without cultured cells.
Advantages and Disadvantages of Using Cell Culture
Biochemists have traditionally used homogenized liver as a source of cells for enzyme or metabolic studies. So, why use animal cell culture which may require far more time in preparation and may require specialized equipment? The major advantage to using cell culture is the consistency and reproducibility of the results that can be obtained by using a batch of cells of a single type and preferable a clonal population. The use of cell culture techniques in toxicological testing may allow a greater understanding of the effects of a particular compound on a specific cell type such as liver cell.
The major disadvantage to using cell culture si that after a period of continous growth, cell characteristics can change and may be quite different from those originally found in donor animals. Cells can adapt to different nutrients. The adaptation involves changes in intracellular enzyme activities. The changes in the growth and biochemical characteristics of a cell population may be a particular problem when using cultures to develop an understanding of the behavior of cells in vivo. After a period of culture, the cells may be significantly different from those that are highly differentiated in vivo where growth has ceased.
Many basic advances in cell physiology, genetics and cancer research have come about through the use of cells grown in vitro. In the middle of the last century, many attempts were made to to culture human cells using tissues obtained from biopsies or surgical procedures. Those cells died after a few days or weeks in culture, most without having divided. These difficulties continued until 1951 when the first cell line called HeLa was succesfully created and grew outside the human body. Thousands of cell lines, representing different human and animal tissues, are maintained in cell banks, such as The American Type Culture Collection (ATCC), the European Collection of Cell Cultures (ECACC) and the Interlab Cell Line Collection (ICLC).
White blood cells congregating in an effort to protect the body from, in this case, unknown pathogenic agents
Source: CDC/ Dr. Gilda Jones
Applications of Cell Lines
An important application of cell lines is the maintenance of renewable genetic resources from particular human patients. This is required for a nmber procedures, from quality control in tissue typing laboratories to linkage analysis and marker-based mapping.4
- Basic cell culture protocols. Jeffrey W. Pollard, John M. Walker
- Animal Cell Culture and Technology. Mike Butler
- Human Physiology: From Cells to Systems. Lauralee Sherwood
- Human molecular genetics 3. T. Strachan, Andrew P. Read