Expression Platforms

Recombinant Protein Expression with a Baculovirus–Insect Cell System

Proteins create cellular matrices, catalyze biochemical reactions, and form signaling pathways to respond to external stimuli. Studies of protein structure and function increase researchers’ understanding about the foundations of life. However, because most proteins are difcult to obtain commercially, it is important to establish sources that can provide researchers with plentiful supplies of proteins. In recombinant protein expression, a gene encoding a protein of interest is cloned into an expression vector (usually a plasmid) and transferred into a host cell…

Synthetic Biology for Adapting CHO Cells to Challenging Bioprocesses

Biopharmaceuticals are produced mainly by Chinese hamster ovary (CHO) cell lines, for which advances in protein formats, bioprocesses, and bioprocess control are introducing novel challenges (1). Thus far, those challenges have been tackled either by technical innovations and media optimization or by advances in host-cell engineering (2, 3). Some technical innovations bring further challenges, such as those related to the compatibility of CHO cultures with highly automated bioprocesses and continuous high-density culture modes (4). With regard to host-cell engineering, most…

BioProcess Insider Interview: Greg Bleck, Catalent

Moderator: Dan Stanton, Co-founder and Editor, BioProcess Insider. Featuring: Greg Bleck, Vice President of Research and Development, Catalent. In July 2021, Catalent released its GPEx Lightning expression construct for Chinese hamster ovary (CHO) cell-line development (CLD). Bleck characterized it as a novel combination of the company’s original GPEx retrovector gene-insertion technology, a glutamine synthetase (GS) knockout sequence, and a recombinase gene-insertion system. A key advantage of the platform, Bleck explained, is that it can reduce CLD timelines by three months.…

Biomanufacturing from 2002 to 2022: How Far the Biopharmaceutical Industry Has Come

It has been two decades since the theatrical release of the first Spider Man film with Tobey Maguire, the euro became the official currency for the European Union, and Anne Montgomery and Cheryl Scott began piecing together the inaugural issue of BioProcess International. In celebration of the 20th anniversary of this staple publication in the bioprocessing arena, we compared products and manufacturing capacity in 2002 with those in 2022 and delved into what has driven the changes that have occurred.…

Pseudomonas fluorescens: Cell-Line Development of a Commercially Proven Platform for Biopharmaceutical Manufacturing

A number of factors contribute to delivering a robust, highly productive, and reliable process for manufacturing a therapeutic protein. They begin with a cell-host system and a gene-expression strategy that determine a developer’s ability to optimize growth and expression titers. But for many therapeutic proteins, initial attempts to develop a production process are based on evaluation of limited factors and tend to yield only small quantities or poor product quality. Automation can enable parallel building and expression screening of diverse…

Plant-Based Protein Expression: Emerging Systems Bring Viable Approaches to Biopharmaceutical Manufacturing

The application of plant-based systems to produce biopharmaceuticals for human and veterinary indications is a rapidly expanding field. Available systems range from stable transgenic root-cell culture to transient expression in whole plants. Products that have been expressed include monoclonal antibodies (MAbs) (1), subunit vaccines (2), virus-like particles (VLPs) (3), specialty enzymes (4), and structural proteins such as collagen (5). “Traditional” bioproduction platforms such as Chinese hamster ovary (CHO) cells, Escherichia coli, and Pichia pastoris have long histories of patient safety…

Posttranslational Modifications and Their Control in CHO Culture

The Chinese hamster ovary (CHO) cell line was first established by Theodore Puck in the 1950s and was used mainly for cytogenetics studies (1). Since the 1990s, CHO cells have increased in popularity as expression host cells because they can be adapted easily into suspension culture and genetically modified. The CHO cell line also has a human-like glycosylation profile (2–4). Therapeutic proteins undergo different posttranslational modifications (PTMs) during manufacturing. Some modifications can lead to undesired effects such as decreased stability,…

Ask the Expert: A Novel Escherichia coli System for Controlled Release of Difficult-to-Secrete Proteins

Although Escherichia coli often enables dependable, highly productive expression of nonglycosylated recombinant proteins, the efficiency with which it secretes a target protein into culture supernatant can depend greatly on that molecule’s physicochemical properties. Some proteins remain trapped in periplasm, thus diminishing process yield and productivity. In June 2021, Marcel Thoen (head of Wacker Biotech’s Global Competence Center for Cell Line Development) described how his company’s improved ESETEC (E. coli secretion technology) solutions can address productivity challenges raised by difficult-to-secrete recombinant…

Avenues for Innovation: The Latest in Cell-Line Engineering and Development

Plato wrote in ancient Greece that “our need will be the real creator,” which transformed over time into the English proverb, “Necessity is the mother of invention.” Advancements in medicine and biomanufacturing technology in 2020 have epitomized that idea. Even as technologies such as mRNA vaccines have rocketed into the public’s awareness, biomanufacturing experts have worked behind the scenes with renewed vigor spurred on by hard lessons from the pandemic. Cell-line development and engineering are no exception. Already undergoing a…

Increasing Expression Titers: New Technologies Could Help Other Cell Lines Catch Up to CHO

Fang Tian is a lead scientist and head of cell biology research and development at the American Type Culture Collection (ATCC) in Manassas, VA. She is a member of both the International Cell Line Authentication Committee (ICLAC) and the US technical advisory group for the ISO/TC276 technical committee. At ATCC, she oversees preparation, authentication, characterization, quality control, and cryopreservation of more than 3,400 accessioned animal cell lines and hybridomas in the cell biology general collection. She holds a PhD in…