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Optimization of recombinant protein production in animal cell culture
Kyselá, Hana ; Španová, Alena (referee) ; Ševčík,, Mojmír (advisor)
V této diplomové práci je popsána přechodná transfekce buněk 293 HEK adaptovaných na růst při suspenzní kultivaci bez přítomnosti séra za použití polyethyleniminů (PEI). Buňky byly transfekovány plasmidem pcDNA5/SEAP, který exprimuje sekretovanou formu lidské placentální alkalické fosfatázy. K porovnání účinnosti jednotlivých transfekcí byla měřena koncentrace exprimované fosfatázy v buněčném supernatantu. Cílem této práce bylo optimalizovat různé faktory ovlivňující účinnost transfekcí s důrazem na nalezení optimálního poměru DNA:PEI.
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Application of tissue culture test plates for production of recombinant protein in HEK293 cells; determination of optimal conditions
Krzyžanková, Marcela ; Španová, Alena (referee) ; Ševčík, Mojmír (advisor)
Efficient production of the recombinant proteins (r-proteins) must be based on previous testing of an expression of a small amount of the r-proteins. This work focuses on optimizing the expression of the r-proteins in 12-well plates. It includes testing of an appropriate speed of shaking, production and transfection volume. It compares all the current testing vessels (it compares a 50-ml centrifugation tube to new tested plates that can substitute the unsuitable tubes). It also compares these new tested plates to production square bottles in order to compare the r-protein expression in the plates to the r-protein expression in the bottles. It monitors effects of carbon dioxide on a number of vital cells, their viability, a relative frequency of positive cells on GFP in various cultivation vessels (plates, tubes, bottles), and pH of HEK 293 cellular cultivation during the 4-day cultivation process as well. On the basis of the results and statistical processing of the results, we have set the optimal agitation speed of 230 rpm for the 12-well plates. We have also set the appropriate production and transfection volume of 2 and 0.5 ml for the 12-well plates. In order to evaluate variables and compare cultivations in all the vessels, the tubes could be substituted by the plates. There is a statistically significant impact of carbon dioxide on the number of cells, their variability, relative frequency of cells (positive on GFP) and pH of the cellular HEK 293 cultivation in the cultivation vessels. There is the strongest r-protein expression in carbon dioxide conditions. The results of this work allow to employ the 12-well plates when we aim to test the expression of the r-proteins in a small amount and in carbon dioxide conditions. On the basis of the findings, the expression of the r-proteins in the 12-well plates and carbon dioxide conditions can substitute the expression of the r-proteins in the production bottle and in carbon dioxide free conditions.
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Transient transfection of a serum free cell culture using polyethyleneimines
Čutová, Michaela ; Španová, Alena (referee) ; Ševčík, Mojmír (advisor)
Master’s thesis deals with the transient transfection of the serum free animal cell culture using polyethyleneimines. In the theoretical part formation of recombinant DNA molecules, used expresion vectores, used DNA transfer and detection of recombinant proteins are discussed. The experimental part deals with efficiency of the polyethylenimine mediated transient transfection under various experimental conditions. 293HEK/EBNA cell line was chosen as an experimental model. First the most effective plasmide - pCEP4/SEAP was selected. Then three transfection methodes were tested: Muller (2005), Durocher et al. (2007) and Backliwal et al. (2008). The highest recombinant protein expresion was reached using the method of Backliwal et al. (2008).
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Development of transient transfection protocol for HEK293 EBNA1 cells
Šmíd, Jiří ; Španová, Alena (referee) ; Ševčík, Mojmír (advisor)
Recombinant proteins belong to considerable biofarmaceutics products used in biomedical research and in the treatment of human disease. Recombinant protines can be produced by stable transfection in big amount or by faster transient transfection with smaller amounts. To provide regular biological activity, it is necessary for the protein to be properly folded and post-translationally modified. As these modifications can be accurately performed only in mammalian cells, they have become the major host for complex r-protein expression. In this thesis is described transient transfection HEK 293 EBNA1 cells with linear polyethylenimines. These cells has been adapted to suspension cultivation in serum free medium. The cells were transfected with pcDNA3.1, pCI, pEBSV1, pCEP4, pEAK8 a pcDNA5/FRT/TO plasmids, everyone contained repoter gene SEAP. Concentration of SEAP in cell culture supernatants were determined in order to compare efficiencies of individual transfections. DNA:PEI ratio was another factor which was optimised and two different PEIs were compared. Highest achieved expresion was 50 mg per litre with transfection in 24 well plate when DNA:PEI ratio was 1:5. Comparison of six different plasmids give the bigest expresion pCEP4/SEAP, in well plate as well as in scaled up system.
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Preparation and study of human lymphocyte receptor LLT1
Bláha, Jan ; Vaněk, Ondřej (advisor) ; Konvalinka, Jan (referee)
Natural killer (NK) cells are an intensively studied part of immune system, possessing unique ability to recognize and induce death of tumor and virus-infected cells without prior antigen sensitization. Their function is regulated by a fine balance of signals induced by multiple activating and inhibitory cell surface receptors and their interaction with the ligands present on the target cell. Recent research in their C-type lectin-like receptors repertoire has shown that ligands of some of these previously orphan receptors lie within their own family, describing a lectin-lectin interaction. This is the case of human inhibitory receptor NKRP1 (gene KLRB1) and its ligand LLT1 (gene CLEC2D). Previous studies have shown that overproduction of LLT1 in cancer cells or lower production of NKRP1 in NK cells is connected to cancerous manifestations. This master's thesis shows a successful production of the extracellular part of LLT1 utilizing a mammalian expression system based on transient transfection of modified human embryonic kidney (HEK) cell lines. It was found that the five cystein residues contained within the lectin domain of LLT1 tend to cause misfolding and formation of aggregates. Stabilization of the domain was achieved by restoration of the sixth cystein residue at the evolutionary conserved...
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Optimization of recombinant protein expression in HEK293 cell line
Bláha, Jan ; Bezouška, Karel (advisor) ; Šácha, Pavel (referee)
Mammalian cells have become the dominant system for recombinant expression of pharmaceutical proteins. This system is becoming suitable also for structural biology, with the advances in methodology of transient transfection of mammalian cells. This work dealt with optimization of recombinant expression in HEK293T and HEK293-6E cell lines in various media using easily quantifiable markers - secreted alkaline phosphatase (SEAP) and green fluorescent protein (GFP). Emphasis was placed on optimizing key factors behind the creation of transfection complex - the ratio of DNA to polyethyleneimine and the amount of DNA used. The positive influence of histone deacetylases inhibitor valproic acid and also of casein hydrolysate Tryptone N1 was also studied. (The thesis is written in Czech.)
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Optimization of HEK293 cell line expression system by regulation of cell cycle and apoptosis
Poláchová, Edita ; Vaněk, Ondřej (advisor) ; Pavlíček, Jiří (referee)
Transient transfection of mammalian cell lines is an effective approach for recombinant protein production, which can provide milligrams to grams of proteins in two weeks from cloning of the corresponding cDNA. Native glycosylated proteins prepared via this approach can be used for various purposes in molecular biology, immunology or pharmaceutical industry, i.e. initial phase of pre-clinical therapeutic protein research. One of the most used mammalian host cell lines is the human embryonic kidney cell line, that can be easily cultivated and chemically transfected. The amount of proteins produced by transiently transfected human embryonic kidney cells can be enhanced by a whole range of factors, i.e. co-expression or direct addition of acidic fibroblast growth factor to the culture medium, co-expression of cell cycle regulating proteins or anti-apoptotic proteins. Expression plasmid pTW5 was prepared and further modified by gene insertion of aFGF, cell cycle regulator p18, p21 or p27 (cyclin-dependent kinase inhibitors) or apoptosis inhibitor bcl-2 or bcl-x. These plasmids were then used for optimization of HEK293T cell line expression system. The impact of every single regulator and their combinations, including hitherto undescribed effect of combination of cell cycle regulator and anti-apoptotic...
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Production and purification of recombinant receptor Clrb
Prokopová, Tereza ; Vaněk, Ondřej (advisor) ; Černá, Věra (referee)
The Natural Killer (NK) cells play a vital role in the nonspecific immunity. They are capable of efficient immunity reaction without any antigen specific receptors on their surface. NK cells recognize non-self molecules and they also recognize their molecules serving as health markers, and absence of these molecules such as MHC glycoproteins on the target cell surface. The NK cells are able to recognize viral infection or tumor transformation in the organism. If natural killer cell is in contact with a cell carrying an abnormally low MHC class I glycoproteins, it will create a signal which informs the cell is infected with a virus. NK cells trigger apoptosis of the target cell without prior stimulation, proliferation and differentiation. They also promote inflammatory responses by the production of chemokines and cytokines. The response is always the interplay of activating and inhibitory signals that the cell receives from its surroundings. The latest research shows that the targeted modulation of NK cells leads to less complications in bone marrow transplantation. They can be potentially used in immunotherapy, e.g. in the treatment of autoimmune diseases. Therefore, NK cells are a highly-studied group of cells. This thesis is focused on a production of Clrb ("C- type-lectin-related protein b")....
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Optimization of Culture Medium for HEK293 Cell Line
Čuperková, Romana ; Vaněk, Ondřej (advisor) ; Šácha, Pavel (referee)
HEK293 is a human cell line derived from embryonic kidney cells and is a frequently used system for the production of recombinant proteins. This work dealt with optimization of the composition of serum-free medium for HEK293S and HEK293T cell lines as a compensation for expensive commercial media. The growth of culture and expression of reporter proteins SEAP and GFP was monitored as the markers. I managed to create a new medium which contained, among other compounds, insulin (1 mg/l), transferrin (5 mg/l) and a mixture of trace elements. During the cultivation in a mixture of commercial medium EX CELL 293 with my new medium 293S cells grew faster than during the cultivation in commercial media (doubling time 20,47 ± 2,68 hours (srel = 13,1 %)). It seems that the new medium is suitable for transfection of HEK293 cell lines with a relatively high expression of recombinant proteins. Transfection ratio of DNA:PEI (w/w) for this medium is 1:2 to 1:3.
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