Smaller, simpler biotherapeutics pave the way for new production methods
Mammalian expression systems have driven the rise of biotherapeutics. Their ability to introduce proper protein folding, post-translational modifications, and product assembly means that they are currently used to produce almost all therapeutic antibodies to ensure correct structure and minimize the risk of immunogenicity. But the advent of smaller, simpler biotherapeutics means that prokaryote expression systems such Escherichia coli (E. coli) are playing a new role in antibody therapy. These bacteria can deliver high expression levels, with simpler bioprocessing at a lower cost together with an extensive molecular toolbox based on well-characterized genetics. This development is increasing the need for sensitive methods to monitor bioprocess development and manufacturing based on E. coli-based expression systems, including the sensitive analysis of host cell proteins.