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Production of a novel type of recombinant IL-2 immunocytokine
Bednaříková, Kristýna ; Vaněk, Ondřej (advisor) ; Černá, Věra (referee)
Interleukin 2 is a glycoprotein that in humans consists of 133 amino acids and is produced by helper T cells to amplify immune responses. IL-2 has many immunostimulatory and immunoregulatory functions and has been shown to activate the cytotoxic function of natural killer cells, T lymphocytes and monocytes, and to promote cytotoxicity of these effector cells. In therapy, when given in higher doses, IL-2 stimulates effector lymphocytes and defends the body against pathogens and cancer cells. When IL-2 is administered in lower doses, it stimulates T regulatory cells that inhibit the immune response, thus maintaining autotolerance. While studies to date have shown that IL-2 is effective in the treatment of malignancies, considerable toxicity has also been observed. In recent years, studies have been published showing that when IL-2 is covalently bound through an oligopeptide linker to antiIL-2 monoclonal antibodies, there is an increase in its biological activity in vivo. Also, this antibody may sterically hinder binding to certain subunits of IL-2 receptor and thus contribute to the selective activation and expansion of natural killer cells and T effector cells, whereas regulatory T cells are not stimulated. The length of the peptide linker plays a key role in the association of the IL-2 with the anti-IL-2...
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The role of N-glycosylation in homooligomerization of natural cytotoxicity receptor NKp30
Tulpa, Matouš ; Vaněk, Ondřej (advisor) ; Bělonožníková, Kateřina (referee)
NK cells play a key role in the defence against cells that have been infected by a virus, a protozoan or have undergone malignant transformation. In addition, they also regulate the activity and quantity of other cells of the immune system. Target cells are recognized using their activating and inhibitory receptors, from which they receive activating and inhibitory signals, on which the cytotoxic response of NK cells depends. There is a dynamic balance between the signals that determines the life and death of the target cell. If activation signals prevail, the target cell will be eliminated. If inhibitory signals prevail, then a cytotoxic response will not be triggered. The NKp30 receptor, which belongs to the immunoglobulin-like receptor superfamily, is an important activating receptor that recognizes a number of ligands, including hemagglutinin of vaccinia and ectromelia virus, human cytomegalovirus pp65 protein, B7-H6, BAG-6, and galectin-3. The extracellular domain of the NKp30 receptor is capable of homooligomerization in solution under certain conditions. The first requirement is the presence of N-glycosylation, the second requirement is the presence of a 15 amino acid long "stalk" domain that connects the ligand binding domain with the transmembrane α-helix. The aim of this thesis was to...
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Preparation of mutated forms of protein B7-H6
Malá, Viktorie ; Vaněk, Ondřej (advisor) ; Bělonožníková, Kateřina (referee)
NK cells are an essential part of the immune system. They are the so-called natural killers and carry several receptors on their surface. Two types of receptors are crucial for immune surveillance, according to their function, called inhibitory and activating. Inhibitory receptors provide auto-tolerance. The second type is activating receptors, whose activation signals toward initiating a cytotoxic response or involving other immune system components (e.g., macrophages). The activating receptor NKp30 (also known as NCR3 or CD337) is a protein of the Natural Cytotoxicity Receptors (NCR) family. It is one of the primary human NK cell activating receptors with potential use in targeted anticancer therapy. NKp30 has an activating ligand protein B7-H6, which is not found on the surface of healthy cells. It is exclusively found on highly stressed cells, e.g., infected or malignantly transformed cells. If a malignantly transformed cell carries B7-H6 on its surface, in most cases, it is recognized and eliminated almost at its formation. Not all tumour cells are B7-H6 positive, so it is possible to visualize them to the immune system through surface decoration with B7- H6. Moreover, such a ligand can be modified to amplify the immune response. This work is based on Pekar L. et al. (2020) publication, which...
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Recombinant expression of the mouse NK cell receptor NKR-P1C
Rudenko, Anastassiya ; Vaněk, Ondřej (advisor) ; Čermáková, Michaela (referee)
NK cells are at the forefront of the body's defense against various threats, such as viruses or cancer cells. NK cells can recognize and destroy harmful cells in several ways that are very different from the defense mechanisms of, for example, T- or B-lymphocytes. NK cells carry a wide range of activating and inhibitory receptors on their surface that distinguish healthy cells from harmful or infected cells. NKR-P1 (natural killer receptor-protein 1) is the first discovered family of NK cell receptors similar to C-type lectins, which includes both activating and inhibitory receptors. NKR-P1C is an activating receptor capable of forming homodimers on the surface of NK cells. The major ligands of the NKR-P1 receptor family are the immunoenvasins of murine cytomegalovirus and other molecules structurally distinct from MHC class I glycoproteins. This work focuses on the recombinant expression of the NKR-P1C receptor protein. Using the pUT7 plasmid, we prepared a stably transfected HEK293T cell line carrying the gene for expression of the extracellular domain of NKR-P1C fused to the Fc fragment of IgG using the PiggiyBac system, and between them, they carry the TEV protease cleavage site. The protein was purified by affinity and gel permeation chromatography, and its purity was subsequently verified by...
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Production of IL-2 fusion antibodies and determination of their biological activity
Frantová, Eliška ; Vaněk, Ondřej (advisor) ; Kubíčková, Božena (referee)
Interleukin 2 is a small cytokine with many important immune functions. It is used mainly as a T cell growth factor, but it also acts on other immune cells, especially NK and NK-T cells. IL- 2 at higher doses induces the differentiation and proliferation of the cell population of effector and memory T cells, which are characterized by cytotoxicity and are able to effectively defend the organism against pathogens and / or tumor cells. In contrast, low-dose IL-2 stimulates the Treg population, which suppresses immune responses and helps prevent autoimmune diseases. However, in cancer therapy, stimulation of this cell population is undesirable. Because free IL- 2 is toxic to the body at high doses, strategies have previously been proposed to potentiate the biological effect of IL-2. One of the most promising appears to be the single-stranded recombinant fusion construct, where IL-2 is covalently linked via an oligopeptide linker to an anti-IL-2 monoclonal antibody (mAb). Based on the findings of the studies of IL-2 / anti-IL-2 mAb immunocomplexes, this immunocytokine (IC) could provide significant therapeutic benefits in vivo, as compared to free IL-2, especially very robust strengthening of biological activity, selective stimulation of specific cell populations according to the selected antibody and...
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Preparation of rat NK cell receptors using HEK293T expression system.
Celadová, Petra ; Bezouška, Karel (advisor) ; Půta, František (referee)
Natural killer cells play a significant role in the immune response against tumor and infected cells. NK cells express a wide variety of surface receptors, including NKRP1, a C-type lectin-like family of both activating and inhibitory receptors. Recently, ligands have been found for some of these previously orphan molecules, some of them lying within the same family. This is also the case of rat Clr-b as a cognitive ligand for rat NKRP1B. It has been shown that in rat, this inhibitory NKRP1B-Clr-b mutual receptor system is subverted by rat cytomegalovirus protein RCTL, a viral version of Clr-b, which serves as a decoy ligand for NK cells. The aim of my diploma thesis was cloning and production of the above mentioned C-type lectin-like proteins based on transient transfection of HEK293T cell line in a suspension culture. This expression system allows us not only to obtain proteins of our interest with a satisfactory yield but also in their native conformation, removing the need for time consuming and often fruitless refolding procedures required in case of using the E. coli expression system. Success was achieved in case of Clr-b and NKRP1B receptors from both WAG and SD strains. Proteins were purified using IMAC followed by gel filtration, identified by mass spectrometry and characterized by disulfide...
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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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Production of interleukin 2 in fusion with monoclonal antibody S4B6
Rožová, Dominika ; Vaněk, Ondřej (advisor) ; Kavan, Daniel (referee)
Interleukin 2 is a growth factor of T cells as well as other lymphocytes, such as NK, NKT cells, dendritic and mast cells, which ensure its expression and secretion. IL-2 regulates immune cell homeostasis and is used to treat a variety of disorders including cancer and autoimmune diseases. In recent years, several cases of interleukin 2 complexed with anti-IL2 antibody have been shown to exhibit dramatically higher biological activity in vivo. These complexes have selective stimulatory activity for different IL2 receptors on target cell. This work follows up previous unsuccessful attempts to express and purify a sufficient amount of the murine IL2 immunocomplex with the S4B6 antibody linked by a 15 amino acid long glycine-serine linker. In this work, a plasmid containing the secreted fusion immunocomplex mIL2-S4B6 gene was prepared and stably transfected to the HEK293T cell line using piggyBac system. The protein was then isolated by chelation affinity chromatography and purified by gel permeation chromatography.
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Production of interleukin 2 in fusion with monoclonal antibody S4B6
Rožová, Dominika ; Vaněk, Ondřej (advisor) ; Kavan, Daniel (referee)
Interleukin 2 is a growth factor of T cells as well as other lymphocytes, such as NK, NKT cells, dendritic and mast cells, which ensure its expression and secretion. IL-2 regulates immune cell homeostasis and is used to treat a variety of disorders including cancer and autoimmune diseases. In recent years, several cases of interleukin 2 complexed with anti-IL2 antibody have been shown to exhibit dramatically higher biological activity in vivo. These complexes have selective stimulatory activity for different IL2 receptors on target cell. This work follows up previous unsuccessful attempts to express and purify a sufficient amount of the murine IL2 immunocomplex with the S4B6 antibody linked by a 15 amino acid long glycine-serine linker. In this work, a plasmid containing the secreted fusion immunocomplex mIL2-S4B6 gene was prepared and stably transfected to the HEK293T cell line using piggyBac system. The protein was then isolated by chelation affinity chromatography and purified by gel permeation chromatography.
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