Dr. Martin Philpott from Auckland Medical School explains that cell lines are made from cells that are immortal, or don't die. An example of an immortal cell is a cancer cell. It keeps growing and dividing uncontrollably. It does not have the triggers that cause it to die.
Dr Martin Philpott Faculty of Medical and Health Sciences, The University of Auckland Most cells from your body won’t grow indefinitely in tissue culture. If you put a single one of your cells, some of them will divide a few times and keep growing and then realise that they are not really supposed to be doing that. All cells in your body have a set lifetime, and they will just over time slowly die out. So all of our cell lines have had to be immortalised in one way or another.
