Monoclonal antibodies (MAbs) destined for use in drug-specific assays must meet specific binding criteria, and therefore require much more in the way of development than many protein-specific antibodies. This article describes one way to facilitate the development of well-characterized, high specificity MAbs. Essentially the same techniques have also been used for producing MAbs that are cancer markers and MAbs that are specific for infectious agents. Monoclonal antibody development, as in other endeavors, requires clearly defined goals and an examination of proposed methods to attain them. This has been succinctly stated by the phrase “Start with the end in mind.” Unfortunately, the vast majority of hybridoma development could be more appropriately described by Yogi Berra, “If you don’t know where you are going, you will wind up somewhere else.” In most laboratories, fusions are carried out with the goal of reducing the amount of cell culture and handling required and using the minimum amount of screening. Little or no consideration is given to ensuring that single clones are subjected to the screening tests. Under these conditions, it is little wonder that dozens of fusions can be carried out, each with the same result — no specific antibody found…
BioProcessing Journal Posts
G protein-coupled receptors (GPCRs) comprise a “superfamily” of cell surface receptors that play a prominent role in cell signalling and are classified into more than 100 subfamilies according to sequence, ligand structure, and receptor function. They are cell surface receptor proteins with seven transmembrane domains which transduce extracellular signals to the interior of cells through heterotrimeric G proteins. GPCRs’ exposure at the exterior cell surface and strong role in cell regulation has provided a rich target family for small compound therapeutics. Of the estimated 35,000 genes in the human genome, approximately 750 encode for GPCRs; half likely encoding sensory receptors, the remaining half representing potential drug targets. Only about 30 of these potential targets are currently modulated by existing pharmaceuticals with approximately 400 remaining potential pharmaceutical targets for validation…
lation components that stabilize the molecule in order to provide the desired product storage stability. Generally, an aqueous formulation is preferred; however, the instability of proteins, both physical (e.g. aggregation) and chemical (e.g. deamidation and oxidation), often necessitates the development of lyophilized formulations. In these formulations, selection of the appropriate stabilizing cryoprotectants, lyoprotectants, and bulking agents is critical. Accelerated stability studies are typically used to evaluate the effect of a single factor at a time in order to identify the optimum pH, buffer, and stabilizing excipients. This approach is limited in that many independent time-consuming experiments must be run, the results are obtained only at the evaluated set points, and additional experiments are required to assess potential interactions between the evaluated factors…
Conventional medical technologies to address tissue and organ dysfunction have resulted in a host of approaches, largely device-based. Examples include maintenance dialysis for renal dysfunction, use of pacemakers, stents, oxygenators, and valves to neutralize the effects of cardiovascular dysfunction, and replacement of large joints with mechanical substitutes. Advances in transplantation science have led to increasing success in replacing diseased kidneys, livers, hearts, pancreata, and lungs. There are, however, significant and severe limitations to these conventional therapies, most notably the demand by a growing and aging population. There is a well-recognized limitation in the supply of tissues and organs. In the year 2000, for example, 77,000 people were awaiting organ transplants, while only 23,000 were performed. High tech medicine is costly; U.S. healthcare expenditures as a percent of gross domestic product are expected to reach 16.7% by 2007…
On January 31, 2003, FDA under the leadership of Commissioner Dr. Mark McClellan, issued a report entitled “Improving Innovation in Medical Technology: Beyond 2002.” One of the goals described in this report is to “speed potentially important emerging technologies to the market by reducing regulatory uncertainty and increasing the predictability of product development.” The technology areas of cell therapy and gene therapy were specifically identified. This article highlights some of the challenges for manufacturers and regulators of these products and describes ongoing efforts at FDA — as well as opportunities to partner with FDA — to improve the product development process for cell therapy and gene therapy products…
A clinical-scale manufacturing process has been developed for the ex vivo expansion of autologous cytolytic T lymphocytes (CTLs) directed against cells infected with the hepatitis B virus (HBV). The process is based on the Rapid Expansion Method (REM) technology originally developed at the Fred Hutchinson Cancer Research Center in Seattle, WA by Greenberg and Riddell. Preparations are underway to initiate a company-sponsored Phase I clinical trial in which REM will be used to expand rare autologous HBV-specific CTLs that will then be infused to patients chronically infected with HBV. Earlier studies have shown that such patients mount only a weak CTL response to HBV. Chronic hepatitis B can lead to severe liver damage such as cirrhosis and hepatocellular carcinoma. By infusing clinical-scale quantities of autologous HBV-specific CTLs into chronic HBV patients, it may be possible to boost the immune system so that it can control the viral infection…