An
immortalised cell line is a population of
cells from a
multicellular organism which would normally not proliferate indefinitely but, due to mutation, have evaded normal
cellular senescence and instead can keep undergoing division. The cells can therefore be grown for prolonged periods
in vitro. The mutations required for immortality can occur naturally or be intentionally induced for experimental purposes. Immortal cell lines are a very important tool for research into the
biochemistry and
cell biology of multicellular organisms. Immortalised cell lines have also found uses in
biotechnology.