Stable expression of recombinant protein therapeutics in CHO cells often relies on random or semi-random genomic integration events which results in a widely heterogenous cell population. This leads to significant effort in clone screening during cell line development in order to identify clones with high expression, growth and product quality.
In this publication, we focus on:
- the development of two targeted integration systems that express high levels of recombinant protein in CHO cells by:
- the installation of rationally designed piggyBac-based chromosomal landing pads
- the use of site specific recombinases including PhiC31 and CRE
- demonstration of the functional integration of several donor vectors encoding various therapeutic proteins including two monoclonal antibodies and one Fc-fusion molecule