Isolation of a HeLa Sub-strain exhibiting Stem-lines of 138 and 148 Chromosomes

IN HeLa strains, the lowest stem-line reported is 68 (refs. 1 and 2), and the highest stem-lines recorded have been 81–90 (refs. 1, 3 and 4), whereas the highest stem-line reported for long-term cultures of human cells (originally obtained from human synovial lining) is 133 (ref. 5). In this laboratory investigations are being undertaken on the possibility of ‘transformation’ of mammalian cells in culture by treating HeLa cells with cell-free preparations obtained from characteristic sub-lines.