Cells of a single type taken from an animal or human and grown in the laboratory. cohort study - A research study that compares a particular outcome, such as lung cancer, in groups of individuals who are alike in many ways but differ by a certain characteristic - for example, female nurses who smoke compared with those who do not smoke.
Population of cells of plant or animal origin capable of dividing indefinitely in culture.
A population of cultured cells, of plant or animal origin, that has undergone a change allowing the cells to grow indefinitely, in contrast to a cell strain. Cell lines can result from chemical or viral transformation and are said to be immortal.