Determining the concentration of viruses is a crucial step in any production process. The most commonly used methods for virus quantification are either based on the infectivity of the virus (plaque assay, TCID50) determination of their genomic material (qPCR), or protein content (SRID, ELISA) and are very cumbersome and time consuming. HPLC analytical methods represent a fast alternative to these assays since they provide information on the virus content and purity in a matter of minutes. Due to the structural properties of the monolithic supports, monolithic analytical columns offer a great advantage over particle based HPLC columns in terms of time and their ability to separate large biomolecules, like viruses, VLPs, pDNA.
In this poster the performance of the CIMac™ Adeno Analytical Column – a monolith based anion exchange column, designed for fast and reproducible analyses of adenoviruses was evaluated. CIMac Adeno column can be used for designing a fast finger printing method that is applicable for monitoring the DSP production process of adenoviruses. Once the basic analytical parameters like linearity and sensitivity are determined using a purified adenoviral standard, the metod can be applied for quantitative determination of adenoviruses.
The challenge of efficient purification of gene therapy vectors
• The most commonly used gene transfer vectors are adenoviruses, lentiviruses, adeno-associated viruses, retroviruses, vaccinia viruses, and pDNA
• Due to their large size and sensitivity to pH, temperature and shear stress, purification is challenging and time-consuming
• A fast and efficient downstream processing purification method is required to isolate sufficient amounts of vectors with the final purity and state that conforms to stringent regulatory demands.
Solution: Convective Interaction Media Monoliths
• Convective interaction media (CIM) monolith chromatography
• Functionalised polydimethacrylate (QA, DEAE, OH, SO3)
• Precisely defined pore sizes
• Radial flow of solute
• Convective mass transfer
A monolith is a stationary phase made of single piece of porous material. Unlike conventional particle-shaped chromatographic supports, the pores of the monolith are interconnected and form a network of channels with diameters ranging around 1500 nm. The binding sites in these channels are highly accessible for target molecules and since the predominant mass transfer depends on convection rather than diffusion, the dynamic binding capacity is flow independent. These characteristics make the monolithic supports suitable for fast separation and purification of large biomolecules such as proteins, DNA and viruses, which sometimes exceed 200 nm in size and thus have low diffusion constants.
In this work we tried to quantify influenza A virus using an analytical CIM monolith column. First a screening of available CIM stationary phases was performed in order to establish the optimal stationary phase for the binding of the virus. The effect of the mobile phase composition and pH on the recovery and peak shape of the virus was investigated. Linearity was examined. The amount of virus in the flow-through and elution fractions was determined with the haemagglutination assay and the purity of the fractions with SDS PAGE. All experiments were performed with an inactivated Influenza A/Wisconsin PZC whole virus sample that was produced in eggs.
Recombinant Adenovirus (rAd) is commonly used for vaccination and gene transfer for cancer applications. This vector is widely used in phase I/II clinical trials. Therefore we believe that upstream and downstream processes should be improved.
We developed a production manufacturing process for rAd serotype 5 n HEK293 grown into disposable fixed-bed iCELLis™ bioreactors (ATMI LifeSciences). The purification process was reduced to one single chromatography step using the Convective Interaction Media, anion exchanger (CIM ® QA monolithic column, Bia Separations).
Briefly, rAd particles were extracted from cells using Triton X-100, depth filtered to discard cell debris, captured and purified out on CIM ® QA. The shallow gradient used for the elution of the vector allowed the separation of different rAd particles populations more or less enriched in full particles. A final step based on Tangential Flow Filtration (TFF) in hollow fibers allowed the removal of remaining impurities and the formulation of the vector batch.
In addition, we developed an analytical method on CIMac™ QA analytical column (Bia Separations) to characterize the different steps of the process, and to track the differences linked to the production runs to increase the robustness of the process. This method provided elution profiles for each step as well as titer of the purified rAd in the final step.
The rAd was produced in an iCELLis™ nano fixed-bed bioreactor (0.5-5.3 m2), purified in a 8mL CIM ® QA monolithic column, scaled up in a medium-scale size 80mL column. We are currently extending the rAd production in a 133m2 iCELLis I000™ bioreactor with a purification step using a 8L CIM® QA monolithic column to purify out up to 1x1015 vector particles.
Monolithic supports represent a new generation of chromatographic media. Due to their large inner channel diameters and enhanced mass transfer characteristics, methacrylate monoliths (CIM® monolithic columns) offer efficient and fast separation of large biomolecules like pDNA, viruses and monoclonal antibodies. High binding capacity for viral particles, good product recovery and resolution are also benefits of monoliths. During loading of MDCK cell-derived H1N1 inactivated influenza virus particles onto monolithic columns, increased back pressure is sometimes observed. This is especially an issue if a large amount of virus needs to be purified since the back pressure depends on the loading volume. The goal of this work was to determine the factors contributing to this effect. We tried to prevent the increased back pressure by treating virus harvests with different precolumn phases (LRATM - Lipid removal agent, Amberlite® XAD 7HP, epoxy monolithic column) and by filtering the virus material before loading it onto the column. To compare different pre-treatment strategies of the virus material the dynamic binding capacity of CIMac QA for virus was first determined, resulting in approximately 1x1013 virus particles per ml. Than loadings of the pre-treated virus material at 75% of the column capacity were performed and mass balances for the virus, DNA and proteins were investigated. Another goal of this work was to find a good regeneration strategy for the columns where increased back pressure occurred. For this reason different regeneration procedures using lipase, benzonase, 2-propanol and NaOH treatment were tested on the columns with increased back pressure.
Traditional waste water treatment usually does not remove or inactivate all of the potentially pathogen microorganisms present in the waste water. This is especially true for enteric viruses that are introduced into the environment through the discharge of effluent from waste water treatment plants - WWTP (Simmons et al, 2011). Although discharged concentrations of viruses are low they can still lead to infection. For some enteric viruses ingestion of only 10 - 100 virus particles is enough to initiate the disease, what calls for very sensitive detection methods. It has been previously shown that CIM-quaternary amine (QA) monolithic supports are a good tool for concentration of viruses in water (Gutierrez-Aguirre et al, 2011). Here we go one step further and evaluate CIM monoliths not just for concentration of enteric viruses but also for their removal from effluent waters.
Potato spindle tuber viroid (PSTVd) is the causal agent of a number of agriculturally important diseases. It is a single-stranded, circular and uncapsidated RNA molecule with 359 nucleotides and no coding capacity. Because of its complex secondary/tertiary structure it is very stable ex vivo and it is easily transmitted mechanically by contaminated hands, tools, machinery, etc. In this work, we describe the development and optimization of a method for concentrating PSTVd using CIM monolithic supports.
Objective – Influenza VLP
• Complex structure
• Different protein components
• Host cell derived lipid membrane
• ESAT6 epitope of M. tuberculosis engineered into influenza hemagglutinin [1,2]
• Optimal vaccine candidates
• Induce strong immune response 
• Contain no genetic information
Over the last two decades,the potential of virus-based biopharmaceuticals for application in gene therapy and vaccination brought new challenges in bioprocess development. Particularly, the downstream processing (DSP) of enveloped viruses shifted from bench-scale towards robust, scalable and cost-effective strategies to produce clinical grade viralvectors. Lenti viralvectors(LVs) hold great potential in gene therapy due to their ability to transduce non dividing cells and their capacity to sustain long-term transgene expression in several target cells, invitro and invivo1. However, despite significant progress, the quality of LV preparations, the purification and the concentration of high titers of these vectors is still cumbersome and costly. In this work, disposable membrane technologies, involving microfiltration, anion-exchange chromatography (AEXc) and a final ultrafiltration step, were the basis for the development of an optimized purification process for LV.
Over the last years, lentiviral vectors have emerged as valuable tools for transgene delivery because of their ability to transduce non-dividing cells and their capacity to sustain long-term transgene expression in target cells in vitro and in vivo. However, despite significant progress, the purification and concentration of high titer and high quality vector stocks is still time-consuming and scale-limited. We aimed to develop a simple and cost-effective capture purification step capable of separating the produced lentiviral vectors from the preparation originally containing a load of recombinant baculoviruses used to transiently transfect 293T producer cells. Even though recombinant baculoviruses do not present major safety concerns1, the final product (purified lentiviral vectors) should be pure enough to be tested in (pre-)clinical studies2. A capture step has been preliminarily evaluated. Both lentiviruses and baculoviruses are enveloped, thus per se prone to degradation through processing. Furthermore, both show overall surface negative charges at physiological pH3,4. As such, our rationale was to use an anion-exchange bind-elute step with enough resolution to separate the two viruses upon elution. It was likely that the difference in the overall electrostatic charges of the two viruses can be used to our advantage if a sufficiently extended salt elution gradient is used.
Biomanufacturing of antibodies, therapeutic proteins and vaccines or gene delivery vectors (either DNA or virus based) is a very complicated process where many things can go wrong. This is even more pronounced as the target biomolecules are extremely susceptible to the environmental conditions both during cultivation (upstream processing) as well as during isolation and purification (downstream processing). One can always doubt whether we have enough information about our complex biomolecule samples to consistently develop a safe product by running a robust and efficient purification bioprocess.
By using and understanding novel technologies one can design new process analytic technology (PAT) initiatives to overcome some of these problems. Here, we present novel monolithic analytical columns — CIMac columns — that can bridge this gap. In the first example, CIMac columns were applied for monitoring the purification process of virus like particles (VLP) which are used for production of vaccines and as delivery systems in gene therapy. In the second example, the monolithic analytical columns were also applied for monitoring the fermentation process of bacteriophages.
Avir Green Hills Biotechnology is developing innovative seasonal and pandemic influenza vaccines based on the deletion of the NS1 gene (del NS1 vaccine).The vaccine is replication-defective and applied intranasally. Recently,clinical phase I studies for H1N1 monovalent vaccine and H5N1 avian influenza vaccine were completed. Both were confirmed to be safe and immunogenic for humans. A production and purification process, which was successfully employed for the pilot-scale production of H1N1 and H5N1 influenza A vaccine virus, will be presented and compared to standard ultracentrifugation method. Details on obtained life virus yields as well as impurity removal will be given. The vaccine virus is produced in static cell culture using Vero (African Green monkey kidney) cells. After clarification the vaccine virus bulk is purified using the same(chromatography-based) scheme for all different subtypes: Concentration by tangential ultrafiltration, AEX chromatography using a CIM QA monolith, and an SEC polishing step allowing for buffer exchange. This purification scheme guarantees the thorough depletion of host cell DNA and total protein. For the ultracentrifugation approach chromatographic steps were replaced by a gradient ultracentrifugation step, comparison data are shown. In addition, an HPLC method for quantifying influenza virus in the vaccine with the use of CIM monolithic columns will be presented and the results will be compared with haemagglutination method.
Rabies virus cause acute encephalitis. It is widely distributed around the globe and more than 55,000 people perish yearly and an additional 10 million post-exposure treatment are reported. About 95% of human deaths occur in Asia and Africa. In countries that are endemic to rabies an immense need for cost-effective large-scale production of the Rabies vaccine occurs. Achieving required quality is challenging because majority of rabies vaccines are produced in Vero cells. This makes Rabies vaccine difficult to manufacture due to low titre of vaccine with lots of residual cellular DNA and serum proteins.
The objective of this work was to improve purity of rabies vaccine regarding residual DNA presence. Different mobile phases with different pH values were explored. Moreover, to develop cost-efficient downstream process for Rabies vaccine, monolith-based purification step was performed in different stages of downstream processing. Chromatographical fractions were analyzed for efficiency of DNA removal. In addition, recovery of Rabies vaccine was monitored. Finally, knowing the optimal conditions, a step-wise gradient was used for purification of larger amount of Rabies vaccine.
Adeno-associated virus (AAV) vectors continue to hold immense promise as gene transfer vehicles for a variety of gene therapy applications. Numerous pre-clinical and human clinical studies have been undertaken with rAAV, employing several of the identified serotypes to leverage their differing tissue tropism to correct a broad spectrum of genetic diseases. Despite the advantageous characteristics of rAAV and the extensive research into pre-clinical applications, production and purification scale-up continues to limit recombinant AAV (rAAV) use in large clinical trials that require even moderate vector doses. Therefore, AGTC has developed a high-yielding, scalable rAAV production system in suspension BHK cells that employs co-infection with two hybrid rHSV-rAAV vectors to provide all cis and trans-acting rAAV elements and the requisite helper virus functions for rAAV manufacturing.
In contrast to traditional, resin-based chromatography methods for rAAV purification, we have developed a two-step chromatographic process that employs a novel anion exchange Convective Interaction Media® monolithic column (CIM® monolith, BIA Separations) capture step followed by affinity chromatography (AVB Sepharose™, GE Healthcare), which yields rAAV vector stocks in very high purity. This scalable process allows significant reduction in processing time due to the high capture step dynamic binding capacity, flow rates and resolution. The resulting overall chromatography recovery compares favorably to our first and second generation processes which used three-step, resin-based column chromatography and membrane-based two step chromatography, respectively.
The CIM QA-AVB process was scaled to accommodate 10 L suspension production runs and was successful at recovering as much as 1 × 1015 purified AAV1 DRP in a single day. The process is highly reproducible and it is applicable for the purification of multiple AAV serotypes with over 95% purity and overall yield of > 30%.
Avir Green Hills Biotechnology is developing innovative seasonal and pandemic influenza vaccines based on the deletion of the NS1 gene (delNS1 vaccine). The vaccine is replication-defective and applied intranasally. Currently, an H1N1 monovalent vaccine is being tested in a clinical phase I study, with an H5N1 avian influenza vaccine soon to be initiated. A production and purification process, which was successfully employed for the pilot-scale production of H1N1 and H5N1 influenza A vaccine virus, will be presented. Data on the selection of chromatographic media, relevant to eliminate downstream purification bottlenecks will also be discussed.
Details on obtained virus yields as well as impurity removal will be given. The vaccine virus is produced in static cell culture using Vero (African Green monkey kidney) cells. After clarification the vaccine virus bulk is purified using the same scheme for all different subtypes: Concentration by tangential ultra filtration, AEX chromatography using a CIM QA monolith, and an SEC polishing step allowing for buffer exchange. This purification scheme guarantees the thorough depletion of host cell DNA and total protein. In addition, an HPLC method for quantifying influenza virus in the vaccine with the use of CIM monolithic columns will be presented and the results will be compared with haemagglutination method.
In an average influenza season, we face hundreds of thousands of influenza cases. Up to 50,000 deaths per year can be ascribed to influenza epidemics. Nevertheless, this is relatively harmless compared to the current, permanent threat of a worldwide pandemic caused by avian influenza.
AVIR Green Hills Biotechnology is developing innovative seasonal and pandemic influenza vaccines based on the deletion of the NS1 gene (ΔNS1 vaccine) . The vaccine is replication-defective and applied intranasally. Currently, an H1N1 monovalent vaccine is being tested in a clinical phase I study and clinical trials with H5N1 avian influenza vaccine will follow in fall 2007.
A production process, which was successfully employed for the pilot-scale production of H1N1 and H5N1 influenza A virus is presented here. The upstream process is performed according to the specific requirements of the respective influenza subtypes. Currently, 15 L batches are produced in cell factories using Vero (African green monkey kidney) cells. The vaccine bulk is purified by using the very same scheme for all different subtypes. For purification, the cell culture supernatant is clarified by centrifugation and the virus is concentrated by tangential ultra filtration. The concentrated virus is subsequently purified in two chromatographic steps which were co-developed with BIA Separations d.o.o.: First, an anion exchange monolithic column is used. This is followed by size exclusion chromatography for polishing and buffer exchange.
This purification scheme guarantees the thorough depletion of host cell DNA and total protein, and recovers at least 25% of the infectious virus.
During last decades different methods for purification of influenza viruses have been described. Most of these methods were developed for purification of egg derived influenza virus which is still the main production system for influenza vaccine viruses. Since cell culture based technology is gaining more and more importance, the need for alternative, efficient and scaleable purification methods has risen. Chromatography is becoming a method of choice for purification of viruses. Relevance of this technique was recently demonstrated also for influenza viruses. Methacrylate monoliths are characterized by large channel diameter, high surface accessibility and convective mass transport. As a consequence they have high binding capacity for large molecules, enable high flow rates at low pressure drop and therefore increase productivity. Recently it has been proven that methacrylate monolithic columns can also be used for purification and concentration of different viruses.
It was the purpose of this work to explore possibilities for purification of influenza viruses on ion exchange methacrylate monoliths. Different subtypes of influenza A and influenza B virus were tested employing various ion exhange monolithic columns.
During the last decade important developments in molecular medicine and adenoviral vector design have been achieved, leading to an increased use of adenoviral vectors in clinical gene therapy protocols. One of the main advantages of the adenovirus is their ability to replicate at high titres in permisive cell lines. The availability of large quantities of adenoviral vector preparations is recognized as an important limitation to pre-clinical and clinical studies. Consequently there is a global focus on large scale production of adenoviral vectors, providing high titres combined with fast, effective and reliable purification methods.
Viruses have proven to be useful vectors for gene therapy purposes. As therapeutics for human use they must be pure and contaminant free. Traditionally, viruses are purified by complicated and time consuming methods such as CsCl density gradient centrifugation or similar. In recent years liquid chromatography has became interesting method for virus purification. It provides high level of purity required for human use and increases productivity. Traditional chromatographic supports were mostly designed for purification of proteins and as such are commonly inappropriate for viruses. Alternative to traditional chromatographic support are methacrylate monoliths (CIM monoliths), characterized by large channel diameter, high surface accessibility and convective mass transport.
The aim of this work was to characterize CIM supports for separation and possible purification of a model virus Tomato mosaic virus (ToMV) from crude plant material.
Traditionally, viruses are purified by time consuming methods such as CsCl density gradient centrifugation or similar. These methods are often inefficient and limited to small scale. In recent years different methods for virus purification, based on ion exchange, gel filtration and affinity chromatography have became popular. Recently, CIM® disk monolithic columns were used for successful concentration of two plant viruses (1) and for improved detection of two human viruses (2). Cucumber mosaic virus (CMV) and Tomato mosaic virus (ToMV) were concentrated and subsequently detected from extremely diluted samples in which they were initially undetectable. Successful concentrations of both viruses encourage us to explore the possibilities of CIM® supports for virus purification. As a model virus ToMV was selected. ToMV is a rod shaped plant virus with a typical size of 300 x 18 nm and isoelectric point at pH 4.6.