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Preparation of expression vectors for receptor NKp30 and its ligands B7-H6 and BAG-6
Pažický, Samuel ; Vaněk, Ondřej (advisor) ; Milichovský, Jan (referee)
NK cells, the cells of non-adaptive imune system, are able to recognise viraly infected or oncogenous cells by many inhibiting and activating receptors that are expressed on their surface and eliminate them consequently. For NKp30, activating receptor of NK cells included in NCR (Natural Killer Cell Receptors) family, lately there were identified several ligands, including membrane protein B7-H6 expressed on oncogenous cells surface and BAG- 6, cell core protein with wide spectrum of functions. Aim of this thesis was preparation of expression vectors coding for receptor NKp30 and his ligands B7-H6 and BAG-6, enabling expression of these proteins in HEK293 cell line. Keywords: NK cell, plasmid, receptor, NKp30, B7-H6, BAG-6
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Structural biology of complex of rat NK cell receptors NKR-P1B and Clrb
Dvorská, Anna ; Vaněk, Ondřej (advisor) ; Ingr, Marek (referee)
The Natural Killer (NK) cells have an important role in the nonspecific immunity of the or- ganism. They have the ability to identify and to kill tumor cells and cells infected by a virus without preceding sensitization by antigen. Their function is directed by the amount of sti- mulation and inhibition receptors interacting with ligands on the tumor or infected cell. This thesis focuses on the preparation and the study of the complex of rat NK cellular inhi- bition receptor NKR-P1B ("natural killer cell receptor - protein 1B") and its ligand Clrb ("C-type lectin-related ligand b"). The Clrb initiates the inhibition of NKR-P1B, meaning that if the cell express Clrb, it won't be destroyed. If the cell gets infected by the rat cytome- galovirus, it loses Clrb from its surface and its destruction is therefore no longer prevented. Cells infected with this virus defend themselves from destruction by expression of the viral gene of C-type lectin RCTL, which is a homolog of Clrb. Transient transfection of human embryonic kidney 293 cell line with simple glycosylation (HEK293S GnTI− ) was used for the recombinant preparation of the soluble form of these two receptors of the rat NK cells. The native forms of the receptors - disulfidic homo- dimers - were prepared as the fusion construct with IgG Fc (using...
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Preparation of glycosylated form of human immunoreceptor NKp30
Kalousková, Barbora ; Vaněk, Ondřej (advisor) ; Moserová, Michaela (referee)
NK cells (natural killer cells) play a key role in innate immunity. Their function is to recognize and kill infected, stressed or malignantly transformed cells. A range of surface receptors promotes this recognition. Cytotoxic mechanisms, lead to induction of apoptosis in the target cell. Receptor NKp30 is one of cytotoxic reaction triggers. It belongs, with NKp46 and NKp44, to NCR (natural cytotoxicity receptors) family. This work describes preparation of NKp30 receptor with natural and simple glycosylation in expression system of human embryonic kidney cell line 293 (HEK293). It was found that glycosylated receptor NKp30 forms noncovalent oligomers. Equilibrium is formed in solution between oligomers and monomers. Oligomerization depends on glycosylation, deglycosylated protein doesn't form oligomers. A recombinant endoglycosidase ENDO F1 was prepared for purposes of deglycosylation.
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Studies on interactions between natural killer cell lectin receptors and their protein ligands.
Hernychová, Lucie ; Novák, Petr (advisor) ; Drbal, Karel (referee)
NK cells are innate lymphocytes which constitute the first line of organism's defence against infections through their receptor system. These cells represent an important part of antiviral and antitumor immunity, they also play a role in transplant immunity, autoimmunity and reproduction. This diploma thesis inquires into the structure of the transmembrane receptor NKR-P1B of mouse NK cells and the interaction with its ligand Clr-b. The aim was to prepare the expression vector coding the ligand-binding and whole extracellular region of the receptor NKR-P1B and to optimize its production and refolding in vitro. Purified protein samples were analyzed by size-exclusion chromatography, electrophoresis and mass spectrometry. Interaction between NKR-P1B and Clr-b proteins was tested using biophysical (size-exclusion chromatography and surface plasmon resonance) and biological methods (labelling of cellular sample with NKR-P1B proteins marked with fluorescent dye). In vitro binding experiments have not confirmed mutual interaction between NKR-P1B and Clr-b despite the prepared proteins binding to the bone marrow cells.
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Preparation of the human NK cell receptor KACL
Nový, Jiří ; Vaněk, Ondřej (advisor) ; Moserová, Michaela (referee)
NK buňky neboli přirození buněční zabíječi jsou důležitou součástí imunitního systému organismů. Jejich specifickou vlastností je to, že dokážou rozeznat a zneškodnit některé nádorové buňky a buňky infikované virem bez jakéhokoliv předchozího signálu. Jejich funkce je závislá na aktivitě povrchových stimulačních a inhibičních receptorů, které se aktivují interakcí s ligandy na povrchu cílových buněk. Interakce lidského NK receptoru NKp65 a ligandu KACL je velmi specifická, což potvrzuje velmi vysoká afinita interakce, která je oproti jiným příbuzným komplexům až 400× vyšší. O tomto komplexu je zatím známo jen málo informací, ale je jisté, že se účastní imunitních procesů v kůži, neboť KACL je produkován výhradně keranocyty. Náplní této bakalářské práce byla příprava rozpustné formy receptoru KACL za pomoci rekombinantní exprese proteinů v lidských embryonálních ledvinných buňkách s homogenní glykosylací (linie HEK293S GnTI- ). Protein byl následně charakterizován gelovou chromatografií a SDS elektroforézou. Správné zapojení čtyř cysteinů do dvou disulfidických můstků bylo ověřeno hmotnostní spektrometrií. S připraveným proteinem KACL bylo zahájeno strukturní studium metodou krystalizace proteinů.
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Preparation of expression vectors for NKp65 and KACL, new members of human NK cell receptor family
Mikulová, Barbora ; Vaněk, Ondřej (advisor) ; Hlouchová, Klára (referee)
Natural killer cells create an important part of innate immune system. Their importance lies in their ability to recognize and kill abnormal cells, especially tumour cells and virally infected ones, without previous activation. To recognize their targets, NK cells use a wide variety of surface receptors, both activating and inhibitory. If a ligand binds to an NK receptor, immune response is triggered. Examples of such ligand-receptor pairs are NKp80-AICL and NKRP1-LLT1 on human lymphocytes. Another ligand-receptor system of this kind is NKp65 and KACL, two recently discovered lectin receptors on human immunocytes. KACL is the last and most recently characterized member of CLEC2 receptor family in humans. Its expression is almost exclusively restricted to skin. NKp65, a close relative of NKp80, is a glycoprotein which stimulates NK92MI cell cytotoxicity upon KACL engagement. NKp65 has been shown to bind to KACL with a fairly high affinity by surface plasmon resonance measurement. This thesis aims at describing the cloning of expression vectors coding for NK cell receptors NKp65 and KACL, expression of these proteins in HEK293T cell line and their purification. Keywords: NKp65, KACL, NK cell, lectin, receptor, plasmid (in Czech)
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Receptors of NK cells
Hernychová, Lucie ; Novák, Petr (advisor) ; Pavlů, Barbora (referee)
NK cells play an important role as a part of the innate immune system, they however share many common features with cells of the adaptive immune system and they can modulate their functions as well. NK cells recognize non-self molecules (induced by viral infection or tumor transformation) through a wide variety of receptors on the cell surface. They also express receptors specific for their own structures, MHC glycoproteins. NK cells distinguish infected or transformed cells according to the quantity of these molecules on the target cell surface. Then NK cells allow apoptotic signals to cause cell death or the tolerance is established. They also promote inflammatory responses by the production of cytokines and chemokines. NK receptors can be grouped into activating, inhibitory, adhesion, cytokine, and chemokine receptors depending on their function. Based on interactions with appropriate ligands, NK cells exert cytotoxicity or they are inhibited. Moreover, their functions are influenced by the cytokine microenvironment. NK receptors can be also divided into C-type lectin and immunoglobulin superfamilies according to the structure. Ly49, NKG2/CD94 and NKR-P1 are receptor families that belong to the C-type lectin glycoproteins. These molecules have a type II transmembrane protein orientation and they...
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Impact of NKR-P1 polymorphism on Ly49 receptors expression in hybrid mouse strains (C57BL/6 x Balb/c, F10-12)
Holubová, Martina ; Fišerová, Anna (advisor) ; Vomastek, Tomáš (referee)
Impact of NKR-P1 polymorphism on Ly49 receptors expression in hybrid mouse strains (C57BL/6 x Balb/c, F10-12) Abstract Natural killer (NK) cells constitute the subpopulation of large granular lymphocytes which mediate spontaneous immune response against infected, transformed or allogeneic cells and thus represent an important component of the innate immunity. NK cells express a wide repertoir of surface receptors which can be either activating or inhibitory and which mediate NK cell recognition and regulation of cytolytic activity. NKR-P1 and Ly49 receptor families belong to the most important murine NK receptors. Both NKR-P1 and Ly49 families are members of C-type lectin-like superfamily of receptors encoded by natural killer gene complex (NKC) on chromosome 6 and include both activating and inhibitory members. The aim of this diploma thesis was to elucidate the impact of Nkr-p1c gene divergence on Ly49 receptors expression and to find out whether the Ly49 and Nkr-p1 gene clusters (which are localized on opposite ends of NKC) are inherited independently or whether the NKC domain is inherited as a complex. The second research interest was to illustrate the influence of the above mentioned divergence on cytotoxic activity of NK cells and tumor growth. In this study, inbred mouse strains C57BL/6 and Balb/c...
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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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