No abstract

Centrifugal elutriation was used to produce cell cycle enrichedfractions of four commercially relevant recombinant cell lines,chosen to allow for variation in properties due to construct,expression system and parent cell type, from normally growingheterogeneous batch cultures. As these fractions had identicalculture histories and had not been subjected to any insult orstress which was likely to have adversely affected cellularmetabolism, they were ideal for further study of cellularproperties. Specific productivity, cell size and cell cyclestate of replicate elutriated fractions were measured for eachcell line. Results showed that cell size was the major cellulardeterminant of productivity for all cell lines examined. Productformation was not restricted to any particular cell cycle phaseand in all cases, production occurred irrespective of cell cyclephase. Specific productivity was lowest when the majority ofcells in the fraction were G(1), intermediate when themajority of cells in the fraction were S phase and greater whenthe majority of cells in the fraction were in G(2)/M. However, the evidence suggests that size is the major cellulardeterminant of productivity; the apparent relationship betweencell cycle and productivity is secondary and can simply beascribed to the increasing size of cells as they progress thoughthe cell cycle. Thus, in addition to cell density and viabilitycell size is the cellular parameter which should be incorporatednot only into mathematical models of recombinant mammalian cellproduction processes but also into process monitoring andcontrol strategies.

No abstract

No abstract

Cell synchronization methods have provided effective tools in cell cycle research along with the development in control of proliferative diseases and in vitro cell growth. Several chemically induced synchronization methods, for accumulating and isolating cells in the various phases of the cell cycle have been developed for adherent and non‐adherent cells, and although widely accepted they have major drawbacks. Physical methods such as centrifugal elutriation do not perturb cell cycle progression and produce highly synchronized viable cell populations. In this article, conventional and recent developments of methods for cell synchronization for various cell types and for monitoring and measurement of cell cycle and cell cycle phase duration are described.