Sample displacement chromatography exploits the different relative binding affinities of components in a sample mixture to achieve accummulation of a desired substance on the column before elution. In pharmaceutical applications, requirements for purity and efficacy of plasmid DNA (pDNA) as a therapeutic product are stringent. The separation of linear, supercoiled (sc) and open-circular (oc) pDNA isoforms has already been established on CIM® butyl (C4 HLD) monolithic columns at preprative scale. This process requires high concentration of ammonium sulphate for loading which increases the overall production requirements. Competing adsorption in sample displacement chromatography utilises the binding capacity of the chromatographic resin more efficiently and increases productivity of the chromatographic step.
This application note investigates three monolithic chromatographic supports with different hydrophobicities regarding their applicability for sample displacement of pDNA. CIMac™ C4 HLD (butyl, high ligand density) as a commercial product and pyridine and histamine as custom immobilised columns are compared.
Plasmid DNA (pDNA) as a pharmaceutical product has stringent requirements of purity and efficacy and often one or more chromatographic steps are used in the downstream process. High ligand density butyl-modified chromatographic monolith (CIMmultus™ C4 HLD, part of CIMmultus™ HiP² Plasmid Process Pack™ 1-1, product number 100.0011-2) is currently used in a polishing step of a pDNA purification process (1), is mainly used for separation of supercoiled (sc) pDNA separation from open circular (oc) and linear pDNA isoforms as well as for removal of remaining gDNA and RNA.
This application note presents a comparison of two different polishing processes employing monoliths, namely bind-elute (BE) and the more recently described (2) sample displacement purification (SDP).
DNA immunization can potentially induce both, humoral and cellular immune responses, and thus comprises an attractive approach for the development of an effective vaccine against HCV. The pIDKE2 plasmid is the main component of the CIGB's candidate vaccine against Hepatitis C virus (HVC), which is being used in HCV chronically-infected individuals during clinical trials phase 1 and 2.
In order to satisfy the high demanding plasmids consumption for clinical trials, the downstream process was improved to reach the quantities need it for clinical trials.
Filamentous phage M13 is a rod shaped non-lytic bacterial virus. M13 genetic material is used for many recombinant DNA processes, and the virus has also been studied for its uses in nanostructures and nanotechnology. The phage has been intensively studied for purposes of phage display and as a delivery vehicle for gene therapy. Phage display was first demonstrated with M13 bacteriophages and the filamentous phage remains a workhorse for this technology. Because of its typical size and rod shape it is considered as a challenging for purification. With large and highly interconnected pores monolithic chromatographic supports are also bridging that problem.
The ability to improve the purification process of M13 and other phages can have a significant impact on the market. By using phages for gene therapy, there will be a decrease in manufacturing time and production costs while enhancing the gene insertion. For phage display, a quicker method for phage purification will allow this powerful tool, which shortens the new drug discovery path and illuminates the basic interactions between different proteins, to be used with higher frequency.
Bacteriophages are used in a broad range of applications, including phage therapy and phage display. With the growing problem of antibiotic resistance leading to untreatable bacterial infections, they are becoming very interesting as antimicrobial agents, not only in medicine, but also in veterinary medicine, food industry and agriculture. Phages intended for use as antimicrobial agents, especially those for human use, need to be purified of contaminants.
Here we present efficient single step purification method for a Staphylococcus aureus phage VDX-10 from bacterial lysate on a CIM® QA Disk Monolithic Column (Figure 1). The described method can be used also on a larger scale using a CIM® QA-8 mL Tube Monolithic Column (Figure 2).
Bacteriophages, viruses that infect bacteria, are being used as antibacterial agents, in phage display screening, as gene therapy delivery systems, and for bacteria typing. To use phages in these applications, they must be free of all impurities. A purification and concentration process was recently developed using an ion exchange monolithic column . One of the key challenges faced in phage purification is the monitoring of genomic DNA (gDNA) released to the growth medium which can interfere with the various applications of phages. CIMac™ DEAE Analytical Columns can be used to monitor the fermentation process, evaluate the amount of degraded gDNA to determine the optimal fermentation endpoint and then to efficiently purify the phage particles.
As the demand for plasmid DNA (pDNA) based gene therapy and vaccines increases, large scale, cost effective, and reproducible pDNA production will be required. The key to success is a real time in-process control method that ensures a high percentage of supercoiled pDNA in the final product. CIMac™ pDNA Analytical Column allows the monitoring of degradation products (open circular and linear pDNA), the removal of impurities (RNA), and ensures that each production step is yielding the amount of supercoiled pDNA anticipated.