Immortalised cells are those which grow and divide indefinitely, due to genetic mutation or targeted genetic engineeringGenetic engineering is a broad term that refers to the manipulation of an organism’s genetic (DNA). Immortalised cell lines bypass the Hayflick limitThe maximum number of replications a cell can make before cell division stops. Specifically, it desc and are therefore useful for processes that require an unlimited source of cells that are genetically identical, such as research investigating properties unique to a cell type, or production of therapeutic proteins (e.g. antibodies for clinical use). Immortalised cell lines that are not well characterised can show abnormal traits or mutate with increased time spent in culture.