Monoclonal antibodies constitute a significant percentage of the protein-based therapeutic molecules currently in clinical trials. The broad applicability and proven commercial success for this class of molecules suggest a larger future market potential. The current biopharmaceutical manufacturing capacity is widely anticipated to be a rate-limiting factor in the growth of the biotech sector. Because antibody therapeutics represent such a large part of this market, and because the therapeutic dosages of antibodies tend to be greater than most biopharmaceuticals, there is an immediate need for novel antibody manufacturing approaches that deliver significantly greater productivity…
BioProcessing Journal Posts
Over 25 years have elapsed since Kohler and Milstein electrified the immunology community with their article describing the reliable preparation of monoclonal antibodies (MAbs) by fusing immune splencytes with immortalized myeloma cells. This discovery not only garnered the pair of scientists a Nobel Prize, but also led to the development of a technology which has yielded a number of important therapeutic, prophylactic, and diagnostic products for in vivo human use, and hundreds of in vitro diagnostic products. Some of these products proved to be significant in meeting previously unmet medical needs, and a few have been commercial successes. But the path, from Kohler and Milstein’s discovery to commercial products, was discontinuous and a bit bumpy, and the technology continues to evolve…
Xenotransplantation has been defined by the US Public Health Service (PHS) as any procedure that involves the transplantation, implantation, or infusion into a human recipient of either (a) live cells, tissues, or organs from a nonhuman animal source, or (b) human body fluids, cells, tissues, or organs that have had ex vivo contact with live, nonhuman animal cells, tissues, or organs (PHS Guideline on Infectious Disease Issues in Xenotransplantation). In the US, several xenotransplantation clinical trials are in progress under US Food and Drug Administration (FDA) oversight. The PHS and the FDA have issued guidelines and guidance documents to address the potential for cross-species infection posed by the use of xenotransplantation products in humans. To minimize the infectious disease risk, these documents provide recommendations on how to screen and maintain source herds, individual source animals, and when possible, xenotransplantation products themselves. However, while precautions can be put in place to remove exogenous infectious agents, the endogenous retroviruses that a source species may carry cannot be removed…
Organizations developing biopharmaceuticals are often faced with the challenge of developing, as rapidly as possible, a production system for a recombinant protein or antibody intended for use in clinical trials. For expression of antibodies and other proteins with complex post-translational modifications, Chinese hamster ovary (CHO) cells are often the host of choice. However, isolation of CHO cell lines producing even moderate levels of a protein of interest is usually a lengthy process due to the need for at least one and usually several gene amplification steps. Gene amplification, which is usually accomplished through the dihydrofolate reductase (dhfr)/methotrexate system, is a requirement for most CHO expression vectors because the absolute expression level from each copy of an integrated expression plasmid is generally very low…
Large scale genomics spurred the development of massively parallel methods of automated DNA purification and sequencing. These methods started with the 1962 development of a 96-well microtiter plate for miniature-scale serology studies. This simple laboratory device has since been greatly modified and extended to include numerous specialty multiwell plates contructed and/or coated with different materials for various purposes. The original 96-well (8×12 matrix) has expanded to include 384-well and higher densities. More recently, functionality and versatility have been greatly augmented by the incorporation of a filter, or thin membrane, into the bottom of the well. These multiwell microfilter plates can thus be employed in a flow-through mode, in addition to the familiar “put in” and “take out” pipetting and rinsing steps associated with traditional enzyme-linked immunosorbent assay (ELISA) microtiter plate methods…
More than 130 drug and vaccine approvals for 95 entities over the last 20 years have generated roughly $30 billion in revenue for the biotech industry. The vast majority of this revenue comes from 30 proteins that have manufacturing bottlenecks resulting from the complexities of consistent protein production. The lag times involved in constructing mammalian cell fermentation facilities keeps supply of immensely successful high-volume drugs like Enbrel, Rituxan, and Remicade well below estimated demand. In other cases, the complexities of peptide synthesis threaten the potential of soon-to-be-launched or recently approved drugs like Fuzeon. The Pharmaceutical Research and Manufacturers of America (PhRMA) has documented more than 371 new biotech drugs in development, supporting the view that demand for many biopharmaceuticals will continue to outstrip supply. That number does not include the multitude of biotech drugs still in research stages…
Peptones are protein digests composed mainly of amino acids and small peptides. Peptones have been used in mammalian cell culture medium as a serum substitute to enhance cell growth and product formation. The first part of this study describes our evaluation of peptones from different sources (soy, wheat, yeast, and casein) on the cell growth and productivity of Sp2/0 myeloma cells expressing recombinant prourokinase (r-ProUK). The results of these studies demonstrated that wheat peptone was the most effective plant peptone to increase r-ProUK yield. Addition of 2 g/L wheat peptone to the culture medium increased batch r-ProUK production between 28-67% compared to cells grown in the absence of peptone supplements. Peptones did not increase cell productivity, but increases r-ProUK yield through increased culture longevity…
Electron microscopy (EM) provides data for viral clearance studies, information on the presence and quantitation of endogenous retroviruses, and the detection and characterization of other potential contaminants. The technique is favored in this field because it is simple, reliable, and can give reliable quantitation for risk assessments. This article describes the main EM techniques currently used for testing cell cultures, culture supernatants, and bulk harvests. It also includes an in-depth description of a thin sectioning technique used to estimate virus titre in culture supernatants and bulk harvests…
Testing for parallelism is a fundamental requirement for assessing the validity of bioassay data used to calculate relative potency. When a test sample and the reference material are diluted and assayed, the assumption is that their dose response curves have an identical shape. The standard statistical approach to demonstrate that two curves are parallel involves testing the null hypothesis for equality. This article explains why that approach is not appropriate and presents an argument for testing the null hypothesis for a specified difference to statistically ascertain parallelism…
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…