Expression Platforms

eBook: Expression Systems — Innovative Techniques for Conventional Cell Lines

Although Chinese hamster ovary (CHO) and Escherichia coli cells have become the biopharmaceutical industry’s preferred platforms for producing recombinant proteins, perennial challenges have limited the capabilities of those expression systems. New CHO lines and improved upstream methods steadily are increasing expression titers, yet researchers continue to decry CHO’s relatively low growth rate. E. coli exhibits strong growth kinetics but cannot perform posttranslational modifications necessary for complex therapeutic proteins. Researchers need advanced technologies and analytical methods to overcome such limitations. This…

Application of Targeted Locus Amplification for Enhanced Apollo X CHO Clone Screening

Speed to market is an important consideration for the development of lifesaving therapies, including recombinant monoclonal antibodies. However, increased speed must be balanced with quality to enable quick and efficient delivery of biopharmaceuticals to patients. Important determinants of quality include the genomic location and integrity of the transgene sequence within a recombinant cell line. Traditional methods of genetic characterization can provide incomplete information and results can be difficult to interpret. However, next-generation sequencing (NGS) approaches such as Targeted Locus Amplification…

Get to IND Faster: Accelerated and High-Performance Cell-Line Development

In April 2020, Samsung Biologics hosted a webinar with John Gill, the company’s director of cell-line development (CLD). He focused first on chemistry, manufacturing, and controls (CMC) activities needed for preparing an investigational new drug (IND) application. Then he introduced a fast timeline for managing CLD programs to accelerate client projects to success. CMC Activities Samsung Biologics is a fully integrated contract development and manufacturing organization (CDMO). Starting with a client’s gene of interest (GoI), Gill’s group tailors CLD to…

Anticipating Cell-Line Challenges to Drive CMC Readiness

Development of a safe and high-quality Chinese hamster ovary (CHO) cell line is of paramount importance for the chemistry, manufacturing, and controls (CMC) portion of studies that support investigational new drug (IND) applications (1, 2). Desirable attributes of a CHO cell line include its ability to produce high titers of biotherapeutic proteins facilitate quick recoveries and selection processes maintain phenotypic and genetic stability throughout in-vitro aging of a culture. A CHO cell line also should be scalable to high-capacity culture…

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…