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2014

One of the major requirements for pharmaceutical-grade pDNA is its high homogeneity, being mostly in supercoiled (sc) isoform. Chromatographic separation of sc pDNA from open coiled (oc) or linear isoform is challenging due to their similar interactions with the chromatographic phases. Promising separation efficiency of pDNA isoforms was proven on recently developed histamine modified monolithic chromatographic column in descending ammonium sulfate gradient. The aim of the study was to further optimise the chromatographic conditions for sample analysis, where all three isoforms would be baseline separated.

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Interactions between antibodies and their antigens are highly selective and therefore immensely popular for affinity chromatography. Consequently, numereous antibody immobilizations were performed on monolithic supports via different activation chemistries in the last decade. Despite the work already done there was no systematic study, where as many as possible activation chemistries were tested for the immobilization of a model monoclonal antibody with subsequent chromatographic characterization of the affinity support. In this work, various preactivated CIM monolithic columns were used for the immobilization of a model monoclonal IgG.

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Monolithic ion exchange CIM® (Convective Interaction Media) columns have been proven in quantitative analysis of different immunoglobulins such as IgM and IgG from human plasma or cell supernatants. The separation mechanism is based on ionic interactions between the ion exchange monolith and immunoglobulin that are controlled by salt concentration. Here we present another possibility of IgM determination based on monolithic CIM® OH columns where the interactions may be controlled by changes in salt concentration or by pH increase. A method for quantitative HPLC determination of IgM in cell supernatant with fluorimetric detection was developed on CIM® OH column (0.34 mL) by means of pH increase. Optimal separation of IgM from cell supernatant matrix was achieved by combining acetate and phosphate buffer in a suitable gradient profile. Two different quantification methods, i.e. calibration curve and standard addition.

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Enrichment of phosphopeptides prior to LC-MS analysis is a crucial sample preparation step because of their low stoichiometry in biological sample, longer retention on reversed phase columns, and lower ionization efficiency compared to non-phosphorylated peptides [1].The use of metal oxides, most prominently of TiO2 enabled efficient and relatively simple phosphopeptide-enrichment. In this study a new monolithic column from BIA Separations containing immobilized TiO2-nanoparticles was tested for its ability to enrich phosphopeptides. The TiO2-column was also tested for possible carryover originating from biological samples. In conclusion, tested monolithic TiO2 columns show significant binding ability for phosphopeptides and are considered as suitable for phosphopeptide enrichment.

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The demand for human immunoglobulin is invariably increasing on an annual basis. To satisfy demands, different manufacturing processes are used to isolate immunoglobulins from human plasma. A quest for alternative paths in manufacturing not only requires development of the most economical manufacturing process, but also a rapid method development and development of reliable analytics for manufacturing monitoring. For an efficient improvement of the purification methods as well as for in-process control during manufacturing stage, the usage of reliable and fast analytical techniques are of crucial importance.

Fast and reliable fingerprint-based method for characterization of immunoglobulin G (IgG) prepared from Cohn I+II+III paste in two chromatographic steps is presented. The fingerprint method bases on partial separation of proteins in linear gradient on CIMac QA 0.1 mL column. Partial separation of proteins does not allow simple quantitative analysis of the samples during the IgG production from Cohn I + II + III paste, however, a very accurate qualitative information about the composition of the sample can be obtained in less than 5 minutes.

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2013

The development of safe, effective, and affordable vaccines has become a global effort due to its vast impact on overall world health conditions. A brief overview of cancer vaccine characterization techniques, especially in the area of high-resolution mass spectrometry, is presented. It is highly conceivable that the proper use of advanced technologies such mass spectrometry, along with the appropriate chemical and physical property evaluations, will yield tremendous in-depth scientific understanding for the characterization of vaccines in various stages of the development. This work presents the physiochemical and biological characterization of two cancer vaccines: Racotumomab and Her1-ECD. Racotumomab monoclonal antibody is a murine anti-idiotypic antibody that mimics N-glycolyl-GM3 gangliosides. This antibody has been tested as an anti-idiotypic cancer vaccine, adjuvated in Al(OH)3, in several clinical trials for melanoma, breast, and lung cancer. The Her1-ECD is a vaccine preparation based on the extracellular domain of HER1 and it is being evaluated in Phase I clinical study in patients with refractory prostate cancer.

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2012

Monolith chromatography media coupled with metal affinity ligands proved superior to the conventional particle-based matrix as a plasmid DNA (pDNA) purification platform. By harnessing the differential affinity of pDNA, RNA. Host cell proteins and endotoxin to copper ions in the solution a majority of endotoxin (90%) was removed from the alkaline cell lysate using CuCl2-induced precipitation. RNA and remaining endotoxin were subsequently processed by copper immobilized metal affinity column employing either monolith or particle-based matrix where both RNA and endotoxin were removed below detection limit with almost complete recovery of pDNA in the monolith was found to have several advantages in terms of handling feedstocks crowded with RNA in a concentration-independent manner and exhibiting flowrate-independent dynamic binding capacity for RNA. This enabled monolith-based process to be conducted at high feed concentration and flow rate. Resulting in pDNA vaccine purification at a high yield and purity and the process conditions investigated, the use of monolith column gave at least three fold higher productivity for recovery of purified pDNA as compared to the particle- based column, demonstrating its potential as a more rapid and economical platform for pDNA vaccine purification.

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The present study describes a new methodology to quantify and monitor the quality of supercoiled (sc) plasmid DHA (pDLIA), using a monolithic column based on anion-exchange chromatography. This analytical method with UV detection allows distinguishing the plasmid isoforms by a NaCl stepwise gradient. The selectivity, Linearity, accuracy, reproducibility and repeatability of the method have been evaluated, and the lower quantification and detection limits were also established. The validation was performed according to the guidelines, being demonstrated that the method is precise and accurate for a sc plasmid concentration up to 200 µg/mL. The main advance achieved by using this monolithic method is the possibility to quantify the sc plasmid in a sample containing other plasmid topologies, in a 4 minutes experiment. This work also intends to evaluate the possibility to assess the sc pDNA present in more complex samples, allowing the control of the samples recovered from different bioprocess steps.

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Glycosylation is one of nature mechanism for invreasing the diversity of protein structures affecting biophysical vjaracterostocs and bioactivity. Glycoproteins exist as mixture of different isoforms ("glycoforms"). In this mixture a group od different glyco components is attached to individual glycosylation site. Different glyco componets attached to the same site may have diggerent effect on biophysical charachteristics of glycoproteins. The type of glycosylation and the degree of heterogenity are important for many reasons starting from stability, activity, clinical efficency (toxicity, pharmacokinetics, immunogenicity), to standardization and patentability.

Thus, it is necessary to separate glycoforms and as much as possible to difine the heterogenity i.e. population of of glyco components attached to the singele glycosysilation site.

External invertase is a widely usef model for studying the influance of the glyco-component on protein stability. External invertase from yeast Sccharomyces cerevisiae has 14 potential N-glycosylation sites in the sequence, 13 of which are fully or partially glycosylated with olygomannans of varying sizes.

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Extensive research in the last two decades has led to the realization of Immunoglobulin M (IgM) as a potential therapeutic and diagnostic agent for autoimmune diseases, infectious diseases and as an AIDS and cancer vaccine. Growing interest in these molecules has created a need for an accurate, rapid and simple analytical method to measure IgM concentrations during the production (in-process control) in cell culture supernatants as well as in all purification steps in the downstream processing.

Convective interaction media (CIM) monolithic columns has been increasingly recognized as a quantification tool for large molecules. Affinity ligands like protein A and protein G are the most common ligands used for antibody capture and analysis.

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There is an increasing demand for highly purified immunoglobulin G since they have found wide range of potential application in immunodiagnostics and immunotherapy.

Human IgG (hIgG) consists of four subclasses (IgG1, IgG2, IgG3 and IgG4) that show differences in some of their physicochemical characterictics and biological properties.

The present research project aims to separate subclasses of hIgG using monolithic stationary phase by SMB technology.

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2010

Application of plasmid DNA for gene therapy and vaccination has gained huge interest in last two decades. Topological homogeneity and impurity content are crucial for therapeutic usage of pDNA. Major influence on achieving regulatory demands in pDNA production has downstream processing and in order to get optimal purity different purification techniques have to be included. It was demonstrated that methacrylate monoliths can be used for efficient purification process of plasmid DNA. High dynamic binding capacities and high flow rates of methacrylate monolith enabled excelent purity and productivity.

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Protein L binds certain types of kappa light chains containing Fv and Fab fragments prepared from antibodies. In the case of IgG's the strong binding affinity refers only to human, mouse and rat species. It offers an advantage over Protein A and G as it binds to kappa light chains regardless of heavy chain subclass and can therefore binds up to 60% of IgG antibodies from human serum sample.

The main goal of our work was the preparation and characterization of CIM Protein L disks. First, Protein L disks with different densities of Protein L on the support were prepared in order to define the dependance of the IgG capacity on the amount of the bound Protein L. Further on, the method of characterization of Protein L disk using IgG was developed. In the end, the stability of the developed CIM Protein L disks in different solutions was tested in order to define the operating and storage conditions.

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2009

Application of plasmid DNA for gene therapy and vaccination has gained substantial interest in the last two decades. Topological homogeneity and impurity content are crucial for therapeutic usage of pDNA. Downstream processing has major influence on achieving regulatory demands in pDNA production and in order to get optimal purity different purification techniques have to be applied. It was demonstrated that methacrylate monoliths can be used for efficient purification process of plasmid DNA. High dynamic binding capacities and high flow rates of methacrylate monolith enable excellent purity and productivity.

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2008

Anion-exchange chromatography is fundamental in downstream processing of plasmids both as a process and analytical technique. CIM anion-exchange monolithic columns have already been successfully used for the industrial scale purification of pharmaceutical grade small plasmid DNA [1].

In this work we report about the use of the newly developed monolithic analytical column intended for plasmid DNA determination in terms of its analytical performance. Higher degree of sensitivity, precision and accuracy is necessary in order to determine the quality of clinical grade DNA intended for therapeutic use. Plasmids purified from Escherichia coli fermentation exist predominantly in the supercoiled form (SC) the other two topoisomers present in the final product are mostly the open circular (OC) and linear forms [2]. Different chromatographic conditions were tested and the separation was optimized in terms of buffer and pH selection as well as in terms of gradient slope and column length. The results were compared to the results obtained with established analytical methods.

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2007

A number of IgM monoclonal antibodies are currently in development for treatment of autoimmune disease, infectious disease, and cancer. Growing interest in these molecules has created a need for an accurate, rapid, simple analytical method to measure IgM levels in cell culture supernatants, and to document the distribution of IgM and protein contaminants in chromatography fractions. High performance protein A columns are used for this application with IgG monoclonals, but IgMs are easily denatured by the harsh conditions required for elution of most affinity ligands. However, IgM monoclonals often exhibit strong retention on either cation exchangers, or anion exchangers, or both, making ion exchange chromatography a potential candidate for this application.

The large size of IgMs makes them a major challenge to particle-based chromatography media. Pentameric IgM has a mass of about 0.96 Md, and hexameric IgM about 1.15 Md. Their diffusion constants are about 2.5 x10-7 cm2/sec, about twice as slow as IgG. Since particle-based chromatography media mostly rely on diffusion for mass transport, both resolution and capacity are im- Figure 4 illustrates a modified anion exchange gradient configuration for monitoring the amount of IgM expressed in cell culture supernatants. A wash step was introduced to better remove con- paired, and increasingly so at higher flow rates.

Monolithic ion exchangers are characterized by an interconnected system of channels with diameters ranging 0.5 to 2.0 microns. This pore architecture supports convective flow, which conserves high resolution at high flow rates.[1] The lack of a void volume removes the major source of dispersion in chromatographic systems. This contributes to sharper peaks, which improves both resolution and sensitivity. Capacity is also conserved at high flow rates. This permits use of a microcolumn format that minimizes assay time and buffer consumption. This combination of features should make monoliths effective analytical tools for IgM.

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IgM can be used for several purposes such as early detection of certain diseases or, when labelled, localized cancer tumours. For their purification commonly chromatography is used. Methods for purifying such big molecules (M.w. around 950 kDa) are usually long and time consuming since these molecules have extremely low mobility therefore mass transfer between mobile and stationary phases is significantly reduced. When purified using affinity mode, serious decrease in IgM activity can occur because of long exposure to low pH in which they are unstable. Furthermore, because of their size, the IgM capacity of convenctional resins is rather low. CIM monoliths were already successfully used for fast separation of large molecules. In this work we tested applicability of anion-exchange CIM monolithic columns for preparation of IgM.

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2006

Gene therapy has already shown some great results in treatment and cure of some monogene diseases, such as diabetes. While the use of genetically modified viruses raises safety concerns, synthetic formulations of genes inserted in plasmids are regarded as safer. At present, most clinical trials involve plasmids smaller than 10 kb. However, the concern that regulation of the functioning of the gene is ensured together with the expectation of the progression of gene therapy to multigene disfunctions, like cancer or complex nevrodegenerative disfunctions (Alzheimer disease), will require the production of larger plasmids [1].

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2005

The Inter-alpha inhibitor protein family is comprised of complex plasma proteins that consist of a combination of multiple polypeptide chains (light and heavy chains) covalently linked by a chondroitin sulfate chain. The major forms found in human plasma in high concentration are Inter-alpha inhibitor (Ial), which consists of two heavy chains (Hl & H2) and a single light chain, and Pre-alpha Inhibitor (Pal), which consists of one heavy (H3) and one light chain (Fig 1). The light chain (bikunin) is known to inhibit several serine proteases, such as trypsin, human leukocyte chistase, plasmin and cathepsin G which are involved in inflammation, sepsis, tumor invasion and formation of metastasis. Recently, a monoclonal antibody against human inter-alpha inhibitor proteins (MAli 6931) was developed in our laboratory.

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Plasmids are excellent genetic vectors and have been widely used in gene manipulation and recombinant DNA technology for a long time. In recent years, plasmids are intensively investigated for gene therapy purposes and genetic vaccination. In this case, plasmid DNA (pDNA) of high purity is required. To follow such demands, several chromatographic steps are commonly needed. In the case of buffer compatibility, columns can be connected in-line to overcome time consuming and yield lowering multiple chromatographic steps. Since each of the unit operations contributes to the dispersion, the resolution is further decreased by each chromatographic step. This drawback might be surmounted by combining several chromatography steps into a single chromatography column. This approach is known as multidimensional or conjoint liquid chromatography (CLC).

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