Expression Platforms

eBook: Microbial Expression — The Right Choice for Large Peptides and Small Proteins

Although animal cell culture has dominated the biopharmaceutical industry for some years now, microbial expression remains important for producing proteins that don’t require posttranslational modifications — or only those that prokaryotic microbes can perform. It also offers an affordable option for antibody fragments and gene therapies. Microbes may be less fragile than animal cells, and they do require simpler media, but they present other challenges related to temperature management and oxygen transfer in culture. Wherever practical, bacterial expression is preferred…

Improving Bioprocess Expression Systems: A Clean Alternative to CRISPR/Cas9

Chinese hamster ovary (CHO) cells have emerged as a robust platform for bioprocessing serving both early and late-stage biotherapeutic drug supply. However, these cells and other hosts (e.g., HEK293), can be optimized for even greater potential through advanced gene editing. For example, when the endogenous glutamine synthetase (GS) gene is knocked out in CHO cells, a sixfold increase in high-producing cell lines is achieved (1). In another study, CHO with annexin A2 (ANXA2) and cathepsin gene (CTSD) knockouts were introduced…

eBook: Viral Vectors for Vaccines — A Virtual Conversation on Production and Analysis

Although today’s vaccines are safer, more effective, and more accessible than they were even 20 years ago, the emergence of new, complex pathogens has exposed limitations in traditional vaccine strategies. Viral vector vaccines (VVVs) hold great promise for confronting those now-intractable pathogens. Combining the best features of live-attenuated and DNA-vaccine approaches, these next-generation prophylactics seek to harness the infectivity of non- or low-immunogenicity viruses to shuttle antigen-encoding DNA from target pathogens into host cells. The resulting transduced cells then initiate…

Capacity Analysis for Viral Vector Manufacturing: Is There Enough?

Advanced therapy medicinal products (ATMPs) are engineered to replace defective, disease-causing genes to compensate directly for a genetic defect or to encode a therapeutic protein construct (e.g., chimeric antigen receptor, CAR) for disease treatment. In most instances, a viral vector delivers the engineered genetic payload, targeting cells in situ or ex vivo through cellular modification, expansion, and infusion into a patient. Clinical successes of ATMPs bolstered by regulatory approval of products such as Luxturna (voretigene neparvovec-rzyl, Spark Therapeutics), Kymriah (tisagenlecleucel,…

eBook: Addressing Production Complexities — Strategies for Working with Difficult and Susceptible Proteins

All proteins are complex — but some are more complex than others, particularly when it comes to recombinant protein expression and production in commercial quantities. What works in a research laboratory to make a milligram of pure protein for study won’t necessarily work on a manufacturing floor to make kilogram batches for drug-product formulation. An increasing number of technological options are available, however, from a simple switch in expression host or adding folding steps in downstream processing to special genetic…

Creating Novel Cell Lines By Genome Editing: Simplifying Cell-Based Assays and Improving Production of Biomolecules

Cultured cell lines have a diverse range of applications. They are used broadly by cell biologists, clinicians, tissue engineers, biotechnology scientists, and bioengineers. The most important uses of cell culture are in the cell-based assays and production of biologically active recombinant proteins. In recent years, genome editing has been used widely to study the structure, function, and localization of endogenous proteins in cultured cells. However, applying the same genome editing techniques to cell lines also could improve the propagation of…

eBook: Expression Systems — Increasing Productivity and Reducing Costs

Biopharmaceutical manufacturers are facing increasing pressures to improve productivity and reduce time to clinic and market. Increasing productivity begins with selecting the appropriate expression system for each protein. Current efforts to boost expression titers also are focused on implementing selection/screening technologies, engineering Chinese hamster ovary (CHO) expression systems, and accelerating timelines for the development of complex next-generation therapies. BioProcess International asked three representatives of the industry’s leading companies to comment on current expression system technologies and strategies Just fill out this…

Improving CHO Cells for Biomanufacturing

Chinese hamster ovary (CHO) cells have been used in biomanufacturing for decades because of their robust capacity to express a range of proteins, such as therapeutic enzymes and monoclonal antibodies (MAbs) at titers measured in multiple grams per liter of culture. Within the available suite of CHO cell lines, the glutamine synthetase knockout (GS-KO) selection system provides industry-leading speed to the identification of high-producing clones for use in biomanufacturing. The GS-KO selection system allows for identification of multiple-gram/L clones in…

Monoclonal Antibodies: Beyond the Platform in Manufacturing

The vast majority of monoclonal antibody (MAb) production processes are based on fed-batch Chinese hamster ovary (CHO) cell culture and protein A affinity column chromatography capture. Increasing cost-consciousness — among innovator companies as well as biosimilar makers — has many companies looking “beyond the platform” for less expensive alternatives that may provide better results. Here the BPI editors review some state-of-the-art alternatives in upstream and downstream MAb drug substance bioprocessing as well as drug-product manufacturing. The current “gold standard” platform…

eBook: The Commercial Expression Systems Market — What Has Changed in the Past Decade

A decade ago, BioPlan Associates prepared the findings of its 2008 directory of expression system technologies that were being promoted or considered likely to be suitable for commercial licensing for biopharmaceutical manufacturing (1). Due in part to the relatively slow advances in this critical area of bioprocessing, this study remains perhaps the only directory of biopharmaceutical-relevant expression systems available for licensing. Here I discuss aspects of related bioprocessing technologies that have and have not changed in the past decade. Expression…