A couple of new papers have appeared in the past few months describing gene knock outs in CHO cells using ZFNs that conferred properties than enhanced cell productivity or efficacy of a produced model monoclonal antibody. Both papers were authored by groups from Genentech (lead authors) and Sangamo Biosciences and appear in Biotechnology and Bioengineering in print and/or on-line.
The first authored by Cost et al, Biotech & Bioengin. 105(2):330-340, 2010, describes use of ZFNs to knock out bax and bak genes in CHO producing apoptosis-resistant cells. Knocking out both genes results in cells resistant to entering apoptosis under normal apoptotic stimuli - like starvation, or exposure to staurosporine or sodium butyrate - in a scale down bioreactor model. Under such starvation conditions, double knock out cells produced 2-5 fold more IgG than wt CHO in this study.
The second abstract, Malphettes et al, Biotech & Bioengin, published on-line April 8th, again describes the use of ZFNs to knock out the fut8 gene. This resulted in CHO cells capable of producing model IgG1 antibodies that were completely non-fucosylated as compared to the heavily fucosylated antibodies from wt cells. Cell growth and antibody production levels in the fut8 knock outs remained unchanged as compared to the wt CHO cells. Other glycosylation was completely normal.
Among authors listed on both papers is our own Trevor Collingwood, then of Sangamo Biosciences and now a member of Sigma-Aldrich Research Biotechnology.
Posted by Bruce Lehr April 9th 2010.