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…
Tag: <span>protein expression</span>
The Sf-9 insect cell/baculovirus expression system is one of the most commonly used protein expression systems. It is the preferred system for generating large amounts of protein in a short period of time, and it has been successfully used to express several hundreds of different proteins. A representative list of the different proteins made in our laboratory over the past decade with the Sf-9 insect cell/BEVS system is given in Table 1. These proteins are often used in drug screening studies and structure function analysis. Proteins intended for therapeutic purposes are not normally produced using this technology, although a few examples do exist. There is also an unexplored potential for the cells to be used for the production of recombinant viral vectors. Recent reports demonstrating the ability of baculoviruses to express proteins in mammalian cells, with mammalian promoters, indicate that BEVS technology might soon have a major role to play in the field of gene delivery…
It is well known that the characteristics of a cultured cell line do not always remain stable and may change upon continuous passage. Most continuous cell lines, even after cloning, possess several genotypes that are constantly changing. There are numerous selective and adaptive culture processes, in addition to genetic instability, that may promote phenotypic changes in cell growth, virus susceptibility, gene expression, et cetera. Similar detrimental effects of long term passaging of insect cells have also been reported for continuous cell lines. In this paper, we describe the isolation of cell clones from low passage BTI Tn5B1-4 cells (High FiveTM Cells), and report their growth characteristics and high level of recombinant protein production…
The K562 cell line is a human myelogenous leukemic cell which has been used by several groups, including ours, as a vehicle for cell-based vaccines and immuno-gene therapies. The attractiveness of K562 cells is the ease with which they can be cultured, plus the fact that they express very low levels of MHC proteins. Low MHC expression facilitates the use of these cells in patients with different MHC backgrounds, and it may improve the in vivo survival of the cells by delaying immune rejection. Based largely on these properties, we have been developing the K562 cell line as a universal platform for expressing cytokines, tumor antigens, and other immuno-modulating proteins…
Baculovirus expression technology, or BEVS, gained its first broad industry exposure in the early 1980s, primarily through the many papers published by students and post-doctoral fellows in Dr. Max Summers’ laboratory at Texas A&M University (College Station, Texas). This technology fostered popular appeal because of its simplicity and high protein expression capabilities. As more work was done, it became even more evident that this was a very rapid, and relatively inexpensive method for producing proteins. It was also postulated that BEVS would offer a valuable means of producing recombinant proteins for use in human therapy, especially since baculovirus was considered non-infectious to human cells. It was thought that any problems with post-translational modifications of the manufactured proteins could be worked out, and fully functional glycoproteins could be manufactured…