Thursday, August 14, 2008 - 8:30 AM
S145
Engineering of Novel Platform Cell Lines with Phenotypic Traits Advantageous for Bioproduction
Florence Wu, Paula Ravnikar, Xiaoguang Liu, Tasha Williams, Jian Liu, Gregory Vanslyke, Changlin Dou, Peggy Lio, and Laurel Donahue-Hjelle. PD-Direct, Invitrogen Corporation, 7335 Executive Way, Frederick, MD 21704
Much of our industry’s focus to improve productivity of production cell lines has been to engineer higher levels of gene transcription, increase cell densities or manipulate feed culture conditions during the production run. Achieving further significant improvements is debatable due to the many recent advances in all of these areas. Therefore, we are investigating a novel approach that allows engineering of new host cell lines to overcome difficult-to-solve bottlenecks in bioproduction that have not been previously addressed. One example is to design a cell line with tolerance to the high osmolarity of culture medium after concentrated nutrient feeding for high cell density cultures. In recent studies, application of Invitrogen’s RevolutionTM technology has indicated that genetic selection may play a key role in isolating CHO DG44 clones with resistance to high osmolarity. RevolutionTM, which creates a genetically diverse cell population by temporarily inhibiting mismatch repair, appeared to allow the isolation of cells that could tolerate conditions as harsh as 600 mOsm/kg, with treated cells doubling in cell number and demonstrating prolonged viability, compared to untreated cells which did not grow and dropped viability rapidly. Significantly, upon transfection, treated cells tolerated greater numbers of concentrated nutrient feeds in fed-batch systems, resulting in a higher volumetric productivity of monoclonal antibody compared to untreated controls. Taken together, this approach is valuable towards systematically engineering a mammalian host cell with novel phenotypic traits that are both advantageous for bioproduction and as yet not fully exploited.