Vaccine bioprocess development and production
Only clean drinking water can match vaccination in its ability to save millions of lives every year. In the case of the ongoing COVID-19 pandemic, the availability of a vaccine is considered a prerequisite for a return to normal life worldwide. But transforming antigens into robust vaccine products is a lengthy process. In the second article of this two-part series we will look at some examples of how immunoassays can play a key role in delivering reliable vaccine bioassay data to support efficient bioprocess development and production to ensure that vaccine production lots meet targets, time and time again.
Robust, accurate, precise, and time effective ligand binding assay platforms are crucial for the development of advanced bioassays for analyzing therapeutic antibody mixtures due to the inherent complexity of these drugs. This is why Symphogen A/S, Denmark chose Gyrolab system to develop assays to support chemistry, manufacturing, and controls (CMC) release and stability programs, and pharmacokinetics preclinical and clinical studies on Sym015, a novel anti-cancer biotherapeutic comprising two humanized monoclonal antibodies (mAbs).
With the need to increase analytical throughput in biotherapeutic R&D and cell and gene therapy, multiplexing assays can appear to be an obvious approach. There are certainly potential advantages, but also disadvantages and considerable challenges involved in multiplexing immunoassays – assays must be carefully matched to function in the same buffer and in the same analytical range. An alternative approach – to miniaturize singleplex ELISAs and run them in parallel – may be even more attractive.
Immunoassays have become invaluable in the generation of data for preclinical and clinical studies, process development/optimization and manufacture of biotherapeutics, and also for new applications such as determining viral titer in cell and gene therapy. Having confidence in the data based on the accurate and precise determination of analytes in complex matrices means overcoming many challenges. These can include interference that reduces robustness, selectivity and specificity, the poor performance of cross-reacting antibody reagents, and time-consuming methods that threaten time plans. Such challenges can be overcome by choosing the right reagents, using the right approach on the right immunoassay platform to deliver reliable data as quickly as possible.
Harnessing the power of cell and gene therapy involves a large range of analytical methods that can deliver robust results to support rapid data driven decision-making. One assay development team has used immunoassays to track a transgene IgG product. Their choice of immunoassay platform enabled them to generate high quality data that supported Design of Experiments to quickly optimize cell culture.
Cell and gene therapy promises to revolutionize medicine by correcting underlying genetic causes of disease or conferring new functions to cells to combat disease and has already seen spectacular successes in health care, ranging from curing rare eye diseases, to the treatment of sickle cell disease and a number of cancers. Immunoassays can be important analytical tools in cell and gene therapy and the careful choice of an immunoassay platform can improve productivity by boosting workflows, data quality and greatly reducing the consumption of precious samples, for example in detecting antibodies against lentivirus vectors that are commonly used in cell and gene therapy. 
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. 
