Item – Theses Canada

OCLC number
777303269
Link(s) to full text
LAC copy
LAC copy
Author
Sunley, Kevin Michael.
Title
The adaptation of Chinese hamster ovary cells to hypothermic temperatures increases yields of monomeric recombinant interferon-beta.
Degree
Ph. D. -- University of Manitoba, 2009
Publisher
Ottawa : Library and Archives Canada = Bibliothèque et Archives Canada, [2011]
Description
3 microfiches
Notes
Includes bibliographical references.
Abstract
<?Pub Inc> Mild hypothermic conditions (30°C to 33°C) have previously been shown to increase cell specific productivity (QP) of recombinant proteins from mammalian cells. However, this is often associated with a lower growth rate which off-sets any potential advantage of higher product titres. This thesis describes the isolation of a novel population of Chinese Hamster Ovary (CHO) cells that have been adapted to low temperature growth by continuous subculture at low temperature for a duration of 400 days. This adapted cell population achieved a growth rate 2-fold greater than non-adapted cells under low temperature conditions (32°C) while maintaining an elevated level of cell-specific expression of recombinant beta-interferon. The volumetric titre of beta-interferon was enhanced by 70% in stationary cultures and by more than 2-fold by application of a temperature-shift strategy involving a growth to production phase. However, the low temperature-adapted cells were fragile and demonstrated an increased sensitivity to hydrodynamic stress in agitated cultures. This problem, caused by a weakened vimentin intermediate filament network, was resolved by the use of macroporous microcarriers which were demonstrated to entrap and protect the cold-adapted cells. Cold-adapted microcarrier cultures were able to achieve high cell densities (greater than 5x106 nuclei/mL) cultures under hypothermic conditions. This resulted in a 3-fold enhancement of volumetric titre of monomeric beta-interferon compared to the original control culture at 37°C.
ISBN
9780494642795
0494642793