Nowadays, therapeutic monoclonal antibodies (mAbs) are predominantly produced with mammalian cell culture systems such as those using Chinese hamster ovary (CHO) cells. Efforts are underway to reduce the costs of this process to meet the increasing global demand in biopharmaceuticals; meanwhile, cheaper and faster expression systems are being investigated as alternatives. The yeast, Pichia pastoris, has become a substantial workhorse for recombinant protein production. However, the N-linked glycosylation in P. pastoris, namely high mannose glycosylation, is significantly different from that in CHO or other mammalian cells, including human cells. In this study, a SuperMan5 strain of P. pastoris was constructed using Pichia GlycoSwitch® technology to successfully produce a more mammalian-like immunoglobulin G (IgG) fragment crystallizable (Fc), which showcases the potential of P. pastoris as a next-generation mAb production platform. Importantly, in this study, a strong methanol-independent promoter, PUPP, was applied, which only requires glycerol feeding for protein production. Most P. pastoris promoters used for protein expression are derived from genes in the methanol metabolism pathway, creating safety concerns due to the flammable nature of methanol, especially at large scale. Here, a fed-batch SuperMan5 P. pastoris fermentation was carried out in which methanol induction, as well as its affiliated safety risks, were eliminated. Overall, this study provides insights into the development of safe and cost-effective industrial mAb production approaches independent of mammalian cell culture.
Tag: <span>glycosylation</span>
Glycosylation is one of the most common post-translational modifications in mammalian-expressed biologics, and is considered to be a critical quality attribute of therapeutic glycoproteins. Due to its biological relevance, physiochemical assessment on the glycosylation profile is always important to the success of a drug development initiative. This article describes the combination of experimental design and machine learning techniques applied to characterize and optimize a conventional, non-derivatized glycoprofiling method on glycans derived from a human immunoglobulin using high-performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD). Two independent experimental designs, a 16-run definitive screening design (DSD) and a 28-run central composite design (CCD), were incorporated with a machine learning technique known as “self-validating ensemble modeling (SVEM)” and used to build predictive models for four chromatographic responses. We show that the predictive models created using SVEM on the DSD data reliably predicted the behavior of the chosen responses when applied to CCD validation data. This demonstrates that the DSD is an efficient alternative to the larger, traditional CCD in which the combination of experimental design and machine learning can effectively characterize and optimize analytical methods.
Glycosylation drives protein quality and therapeutic benefits in protein-based therapies. Recently, there has been a push in the pharmaceutical industry to improve the consistency and quality of the glycan patterns on therapeutic proteins like monoclonal antibodies. Post-translational modification begins in the endoplasmic reticulum but is finished in the Golgi where more complex glycans are added. In this study, the addition of lipids via a novel mechanism provided by the medium supplement, Cell-Ess®, improves the consistency in glycan patterns so that they are more reproducible between product batches. The effect of media supplementation with Cell-Ess on the variation of glycan patterns was measured in two different media formulations across two separate experiments. Supplementation with Cell-Ess resulted in a statistically significant reduction in the variation of glycoforms when measured by the standard error of the mean. In addition, to improved consistency, there were increased higher glycoforms or galactosylation. There was also significantly more total galactosylation and significantly fewer lower glycoforms for antibodies produced by CHO cells supplemented with Cell-Ess. These data taken together suggest that the addition of lipids via Cell-Ess results in a more functional Golgi and an associated improvement of protein quality and consistency…
Biopharmaceuticals are predicted to become the main driving force of the pharmaceutical market in the near future. Other than blockbuster products such as erythropoietin, an increasing number of approved recombinant therapeutic proteins are based on antibody technology (e.g., fusion proteins or monoclonal antibodies [MAbs]). In contrast to relatively simple products produced in Escherichia coli bacteria (e.g., insulin), proteins which require complex posttranslational modifications such as glycosylation have to be produced in eukaryotic cells. In this context, production systems have been dominated by mammalian cell culture. Nevertheless, alternative eukaryotic expression technologies based on yeast, insect cells, transgenic animals, or transgenic plants are under development. Plants are a particularly promising alternative to mammalian cell culture because of their excellent safety aspects and estimated cost-efficient upstream/cultivation processes. In addition, plants are well known for their ability to express biologically functional monoclonal antibodies. In comparison to the seed plants most widely used for transgenic protein expression — tobacco, corn, and rice — mosses provide unique, beneficial features…
Today concentrated efforts are underway to improve the bioactivity of therapeutic proteins with the aim of reducing: (i) the number and concentration of the applied doses of the therapeutic protein, (ii) undesired side effects, and (iii) the cost of a therapy. A very promising strategy is to optimise the glycosylation of these biotherapeutics. A novel expression platform, GlycoExpress™, has been developed to produce proteins with fully human glycosylation, optimised sialylation, and improved bioactivity…
Glycosylation, a posttranslational modification that adds sugars to proteins, is required by many proteins to function properly. Glycosylation can modulate the biological activities of monoclonal antibodies (MAbs), including certain effector functions in the Fc region of IgG antibodies. Monoclonal antibodies produced at higher expression levels by mammalian cell culture may contain small amounts of nonglycosylated heavy chain (NGHC). Recent cell culture mini-reactor studies have shed light on the process parameters that most affect the occurrence of NGHC, and have greatly minimized NGHC levels in IgG MAb products…
The baculovirus-insect cell system consists of a recombinant baculovirus vector and its host, which may be a lepidopteran insect larvae or an established lepidopteran insect cell line. Hundreds of different recombinant proteins have been produced using the baculovirus-insect cell system, facilitating biomedical research on protein structure, function, and the roles of various proteins in disease. In addition, many biotechnology companies are using this system to produce recombinant proteins for potential clinical use as vaccines, therapeutics, or diagnostic reagents…
The insect cell/baculovirus expression system typically results in more rapid expression and higher concentrations of recombinant proteins than what can be achieved with other animal cell culture systems. The lack of complex glycosylation in the proteins produced by this system, however, limits its use in the commercial-scale production of therapeutics. Complex glycosylation is required in many cases for adequate protein activity and pharmokinetic characteristics. In contrast to the protein’s primary structure, which is encoded by the genetic material and is constant regardless of the host utilized, the extent of glycosylation is determined by the host, and by the protein itself. Even cells from different tissues of the same organism provide different glycosylation profiles. In addition, culture conditions and the cellular metabolic state can also influence protein glycosylation…