Removal of impurities generated in the production of adeno associated virus (AAV) is an important step as they may pose a serious health risk, as well as deteriorate the economics of the production process. The most critical subsets of these impurities include: host cell nucleic acids, host cell proteins, chromatin, capsid aggregates, capsid DNA complexes and empty capsids.
This poster introduces two new column s for performing separation of empty (E) and full (F) capsids using multimodal approach. A PATfix ® HPLC system with three different detectors, i. e. absorbance, fluorescence, and light scattering in combination with three analytical columns traded as CIMac ™ AAV Empty/Full, CIMac PrimaS ™ (AAV) - Beta, and CIMac ™ PrimaT - Beta by BIA Separations Sartorius.
Adenovirus has after two decades gained new consideration and is now used as a COVID-19 vaccine delivery vehicle. To reduce side effects of the vaccine it’s purity is of utmost importance. Constant enhancement of the vaccine purity and improvement of the impurity detection methods is therefore necessitated. In this work we present second generation adenoviral vectors purification procedure based on monolith chromatography using CIMmultus QA to secure safer product, as well the accompanying analytical tools. The novel industrial process secures better purity at higher yields. The robustness of the process was verified using different upstream materials. Manufacturing of the vaccines in large quantities due to pandemic represent great challenges, mainly in terms of production time and costs. Higher capacity of the CIMmultus QA columns used in this process overcomes the raw material supply bottlenecks.
Density gradient ultracentrifugation (DGUC) is a well established tool for Empty/ Full AAV capsid separation based on density differences between AVV sub-populations. However DGUC practice is laborious and lacks any detection options, therefore fractions must be collected manually and analyzed later. Both of these shortcomings can be addressed by coupling post DGUC workflow to PATfix analytical HPLC. BIA Separations PATfix platform
provides sufficient tools for liquid extraction and fractionation as well as a comprehensive detector suite for precise fraction characterization. Baseline separation of capsid species was achieved in a density gradient of CsCl, producing a centrifugram that reveals information traditional DGUC and anion exchange chromatography cannot.
Removal of empty capsids is a particular goal of AAV purification. Multimodal PrimaT ligand offers new options for removal of empty and also
damaged capsids. Besides it also contributes to better clearance of contaminating DNA. PrimaT works for different AAV serotypes - for example AAV 2/8 and AAV 2/9. AAV 2/8 or AAV 2/9 clarified harvest from Sf 9 cells was first processed by tangential flow filtration (TFF) coupled with Kryptonase treatment to reduce host cell DNA. Initial AAV capture step was performed on CIMmultus SO3 cation exchange column. After elution with sodium chloride gradient AAV fraction was cleared of DNA and protein contaminants. Separation of empty and full AAV capsids was performed by multimodal metal affinity chromatography with CIMac and CIMmultus PrimaT.
AAV9 clarified harvest from Sf9 cells was concentrated and purified using combination of tangential flow filtration, nuclease treatment and cation exchange capture. First part was TFF coupled with Kryptonase treatment. Capture step was performed on CIMmultus SO3 cation exchange column. AAV elution fraction was cleared of DNA and protein contaminants and prepared for final polishing – empty capsid removal. PrimaT separation mechanism is based on ligand multimodality, one of them being metal-chelating ability. This was sucessfully exploited for AAV capsid separation.
Separation of empty and full AAV capsids is important analytically as a means of monitoring the effects of different transfection strategies, cell culture conditions, lysis methods, sample preparation and purification methods. It is at least as important on a prepartive level because it offers the possibility of removing empty capsids without ultracentrifugation. This poster introduces a new column for performing separation of empty and full capsids.
CIMac PrimaS™ (AAV) beta employs a new ion exchange-hydrogen bonding multimodal ligand that provides a new orthogonal option for separation of empty and full capsids. Gross selectivity is similar to strong (QA) anion exchangers eluted with salt gradients, but it generally provides better resolution. Its distinct separation mechanism is documented by the fact that it provides its best results when eluted with increasing pH gradients. This is directly opposite to QA exchangers where increasing pH causes capsids to bind more strongly.
CIMac PrimaS™ (AAV) beta can also be eluted with salt gradients and often provides better resolution than QA, but its best resolution is obtained with pH gradients. Separation of a free capsid protein (CP) occurs only with the pH elution format. CIMac PrimaS™ (AAV) beta can be used instead of classical anion exchange, for example following capture by cation exchange chromatography or affinity. Its distinct separation mechanism also makes it possible to perform orthogonal separations in which it is combined with QA.
Bioreactor cell supernatants or post lysis materials entering downstream purification are heterogeneous mixtures of empty, full, and misassembled AAV capsids mixed with host cell proteins, genomic DNA, chromatin complexes, and other contaminants. Monolith- based HPLC columns provide high resolution among these species but overlap of elution position among capsids and contaminants makes it impossible to estimate the relative content of full and empty capsids by UV absorbance. Simultaneous monitoring with multiple detectors however enables quantitative insights that extend far beyond the limitations of UV absorbance.
This poster demonstrates how the combination of fast high resolution separations with monoliths can be combined with multiple monitors to obtain much deeper characterization than traditional assays. Anion exchange fractionation of filtered lysate and cation exchange- purified AAV 8 was monitored by UV absorbance at 260 nm and 280 nm, simultaneously with tryptophan fluorescence to differentially detect proteins without interference by nucleic acids, and with Multi Angle Light Scattering (MALS) to detect capsids.
Fast, accurate, and meaningful characterization of cell culture harvests and in process samples is critical for both process development and for documentation of in process control. UV analysis of chromatography profiles has been a valuable tool for decades, but it has major limitations with respect to sensitivity and its ability to discriminate the product of interest from particular contaminant classes.
In this study we use filtered lysate containing AAV 8 to demonstrate the ability of a strong cation exchange monolith (CIMac ™ SO3-0.1) coupled with multiple monitors to enable high sensitivity detection of AAV capsids while characterizing the relative distributions of DNA and protein contaminants. This approach can be used to evaluate cell culture methods, influence of harvest time, lysis methods, and effectivity of purification methods across a process.
AAV vector lots are generally a heterogeneous mixture of empty particles (i e do not contain DNA) and full particles (i.e. contain DNA). Different spectrometric based methods can be used to establish the ratio between full and empty AAV particles, but accurate evaluation of empty/full ratio is often obstructed due to complex spectroscopic behavior of empty and full AAV particles, such as poor separation and impurity overlapping. An approach that takes difference in physical chemical properties between empty and full capsids into account overcomes limitations of spectrometric based evaluation of empty and full AAV particle ratio.
Chromatographic separation of empty and full AAV 2 8 capsids was achieved on the CIMac AAV full/empty analytical column (strong anion exchanger, QA quaternary amine chemistry) with the PATfix TM HPLC system using a linear NaCl gradient at pH 9.0 Signal response from three different detectors connected in series was analyzed fluorescence (excitation 280 nm emission 348 nm), light scattering 90 angle, LS) and UV absorbance 260 nm and 280 nm).
Serotype 10 adeno-associated virus (AAVrh_10mCherry) was analysed on the PATfix™ HPLC system with the CIMac™ AAV full/empty analytical column to estimate the ratio of empty and full AAV particles based on the peak area of the chromatogram given with three different detectors. AAV included a protein capsid containing single stranded DNA. CIMac™ AAV column consisted of a strong anion exchanger with QA chemistry (quaternary amine).
Poster was prepared by Blaz Goricar and presented at ISBioTech 9th Spring Meeting where it was awarded the first prize. Congratulations!
This poster presents fully scalable non-affinity purification strategy that has been proven to be effective for all AAV serotype tested to date. Cell lysate is directly subjected to column purification after removal of cell debris without requiring a concentration step using tangential flow filtration. The process consists of three chromatographic steps. Hydrophobic interaction chromatography on a CIMmultus OH monolith is used for initial virus capture and purification. Precipitating salts are used at 1.0–2.0 M to achieve virus binding. Most of the small molecule contaminants and proteins are eliminated in the flow-through. AAV co-elutes with a highly reduced population of contaminating proteins. DNA-protein complexes are very strongly retained and require NaOH for removal. Intermediate polishing is performed with a CIMmultus SO3 cation exchange monolith. The AAV fraction from the capture step is titrated to a pH value of 3.5—5.0 and diluted to binding conditions. Sugars and surfactants are added to suppress non-specific interactions with tubing and containers, and the product is eluted in a salt gradient. Final polishing is conducted on a CIMmultus QA anion exchange monolith which separates empty capsids from full capsids. This is achieved in a salt gradient at alkaline pH. For more information please refer to BIA Application note A048 (www.biaseparations.com/applications).
Chromatography is a useful purification method for large biomolecules and virus manufacturing and it is easily scalable to large production volumes. Convective Interaction Media (CIM) monolithic columns constitute of large flow-through channels and consequently have high surface accessibility of binding sites. Preferences of CIM monolithic columns are flow independent performance, resulting in fast separation, concentration, purification, impurities removal, and analytics of biopharmaceuticals.
The aim of the study was to develop Influenza virus purification platform, which can be used for several virus strains. The main objective was to develop a process with as little as possible of intermediate steps, especially omitting Tangential Flow Filtration (TFF) or other sample pre-treatments with high host-cell DNA and protein removal, as well as to achieve high binding capacity of the Influenza virus per mL of monolithic support.
During recombinant adeno associated virus (rAAV) downstream processing, a large amount of host-cell and product related impurities needs to be removed from the product. Succesful process on laboratory scale, such as Cesium chloride purification, lacks scalability when the process is due to be transfered to larger industrial scale. The aim of the study was to develop robust, fast and effective rAAV virus purification platform, which can be used for several AAV serotypes with various inserts. Lysed harvest and supernatant of rAAV9 were first captured and concentrated on CIMmultus™ OH column, followed by intermediate step on CIMmultus™ SO3 column and further polishing on CIMmultus™ QA column. Derived purity of industrial scale monolith purification product was compared to laboratory scale purification.
New vaccines against Influenza A are required each year to keep up with the most virulent evolving strains. This highlights a need for predictive analytical tools that can aid purification process development and validation. Rapid and reliable quantification of Influenza A virus is therefore of the utmost importance for enabling good yields and controlling the costs of the downstream processing. Here we demonstrate the ability of monolithic chromatography media to produce process predictive profiles that can document ability to remove impurities and obtain high product recoveries.
CIMac™ Analytical Columns are short bed high performance monolithic columns offering all the advantages of CIM® monolithic technology. Their small volume and short column length allow the operation at high volumetric flow rates enabling to receive the information about the product quantity and purity in just a few minutes. Hence, the CIMac™ Analytical Columns can be effectively used for the in-process and final control of various samples from different purification process steps.
Adeno-associated virus (AAV) vectors of various serotypes are considered to have high potential for gene therapy applications. Currently, manufacturing of AAV vectors faces the challenge of co-production of incompletely formed particles lacking a recombinant viral genome. Empty capsids increase the dose of total AAV administered for efficient transduction and are thought to cause unwanted immunological reactions against the virus.Removal of empty capsids during manufacturing, as well as analysis of empty/full AAV particle content is therefore a critical requirement for any AAV production process. This poster demonstrates how CIMmultus™ QA monolithic columns can be used to remove empty AAV capsids from the product chromatographically in a single step.
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.