Most cells can exhibit a biochemical pathway which mediates their own
destruction in a highly controlled and genetically defined manner. In
animal cells, a morphologically distinct form of this 'programmed cell
death' has been identified and extensively characterised. This phenom
enon, which has been named apoptosis, accounts for most of the cell de
aths that take place during the production of biopharmaceuticals from
animal cell lines. In the past few years, the factors responsible for
the induction of apoptosis in the bioreactor environment have been ide
ntified. Furthermore, a growing number of studies have demonstrated th
at the suppression of apoptosis by the overexpression of anti-apoptosi
s genes, most notably bcl-2, result in improved culture productivity.