The Baculovirus Expression Vector System (BEVS) is widely used for the production of a broad variety of heterologous proteins that are often secreted into the culture medium as soluble, biologically active, properly glycosylated, and correctly folded. Downstream purification of a secreted protein is considerably easier due to the absence of many contaminating cellular proteins and nucleic acids in the culture supernatant. The BEVS system has also successfully been used for the production of virus-like particles (VLPs) for a broad variety of proteins derived from many different viruses…
Tag: <span>purification</span>
Proteins and their promise for revolutionizing drug discovery have come virtually full circle in just a few decades. The advent of genetic engineering and the emergence of early recombinant proteins such as insulin and interferon dramatically boosted the perceived value of proteins in pharmaceutical research and of protein drugs in particular. Although the lights dimmed somewhat on the promise of therapeutic proteins in subsequent years, more recent times have seen a resurgence of interest in proteins, particularly monoclonal antibodies. Perhaps most telling has been the dawn of the post-genomic era, which has cast a bright spotlight on proteins, long respected as the work-horses of the cell, for their usefulness in exploring cell function, unraveling biochemical pathways, understanding disease, and for their massive value as novel drug targets…
A growing number of separations’ scientists and process developers are looking beyond protein A sorbents for capture and initial purification of monoclonal antibodies. A variety of strategic and operational goals have prompted examination of alternative immunoglobulin-selective sorbents. Most broadly, many workers wish to eliminate design considerations associated with leached protein A. Also cited is a preference for sorbents that can withstand stringent cleanup using 1 M sodium hydroxide. In some applications, it is desirable to avoid the low-pH elution conditions typically employed with protein A sorbents — conditions that can foster aggregate formation. In still other cases, the target antibody may bind poorly to protein A. Finally, there may be interest in evaluation of immunoglobulin-selective sorbents less costly than protein A sorbents…
Process development is an investment. As with a personal retirement plan, the importance of making the investment is not in question, yet strategies for when, how much, and where to invest in process development vary significantly from company to company. For a personal retirement plan, the answers to these questions are straightforward: invest as early as you can and as much as you can, and take less risk the closer you get to retirement. This would also be sound advice for investing in process development (substituting “BLA filing” for “retirement”) were it not for two complicating factors. First, the majority of biotherapeutics that enter the clinic fail to make it to the market. This makes a large, early investment in process development less attractive. Second, there is extreme pressure to get into the clinic, and subsequently onto the market, as quickly as possible, minimizing the time available for process development…
Parvoviruses are one of the most prevalent infectious agents in the laboratory rodent. Their effect on research can range from immune dysfunction that may mislead researchers when interpreting results to lethal effects on animals. Until recently parvovirus infection in mice was thought to be caused by minute mouse virus (MMV) and in rats by rat viral agents in the KRV or H-1 serogroups. Relatively newly discovered viruses in these groups are mouse (MPV) and rat parvoviruses (RPV-1 and 2). Parvoviruses are 15–20 nm in diameter and are single-stranded DNA viruses of about 5,000 nucleotides, which replicate through a double-stranded DNA intermediate. The protein composition consists of three structural or capsid proteins providing the viral coat (VP-1, VP-2, and VP-3) and two non-structural proteins involved in viral replication (NS-1 and NS-2). Among the capsid proteins,VP-2 is the major protein…
At the onset of modern-day biotechnology, products typically fell into two distinct categories, the traditional high volume, low value products (e.g. beer and industrial enzymes) that had come to characterize the biotechnology industry, and low volume, high cost products. Recombinant proteins, the result of technological advances in molecular biology, have come to typify these latter products. Recombinant protein therapeutics have been hugely successful, potentially outstripping production capacity and continue to drive much of the biotechnology. Meanwhile, many recombinant proteins, those characterized as research tools and reagents, are governed by a price-volume relationship typical of industrial enzymes. In a competitive environment, they are fast becoming commodities — price sensitive, packaged as kits, coupled to instrumentation, and relying on heavy marketing and brand recognition. Ominously, the advantage protein therapeutics have enjoyed with patent protection and regulatory constraints on production is being threatened as patents expire and competition from generics increases…