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Activating antitumor immune response using bispecific fusion proteins
Chytrá, Gabriela ; Vaněk, Ondřej (advisor) ; Černá, Věra (referee)
Natural killer (NK) cells are lymphocytes of the innate immune system that recognize and eliminate transformed and potentially harmful cells in a mechanism termed immunosurveillance. Malignant cells strive to escape immunosurveillance, and if successful, oncological disease develops. To restore immune recognition, immunotherapy utilizing NK cell-directed therapeutic fusion proteins can be employed. Therapeutic fusion proteins target tumour markers expressed on the surface of malignant cells and, at the same time, stimulate immune response through binding to NK cell activating receptors, for example receptor NKG2D or NKp30. A relevant example of a tumour marker is the HER2 receptor, which is often overexpressed in several types of cancer, most notably breast carcinoma. This thesis describes the preparation of several bispecific fusion proteins with potential use in immunotherapy. Bispecific fusion proteins consist of an NK cell activating ligand (ligand MICA or B7-H6) and nanobody targeting selected tumour marker (receptor HER2), which are connected by flexible glycine-serine linker. The constructs of fusion proteins were prepared in two configurations - with nanobody located on the N-terminus and the ligand on the C-terminus and vice versa. In addition, bispecific fusion proteins introducing...
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Study of the interaction of receptor NKp46 with adhesin Epa1
Houserová, Jana ; Vaněk, Ondřej (advisor) ; Pavlíček, Jiří (referee)
One of the key components of the innate immune system are natural killer (NK) cells. The task of these cells is to induce apoptosis in target cells (e.g., cancer or virally infected cells). The target cells are identified by their interaction with surface receptors of the NK cells. On the surface of the NK cells, there are activating and inhibiting receptors. One of the activating receptors is the natural cytotoxicity receptor NKp46. Several ligands of this receptor have been identified, one of them being the epithelial adhesin Epa1 of yeast Candida glabrata. The invasive candidiasis caused by this yeast is a feared complication for patients with haematological diseases. The use of the NK cells in immunotherapy includes bispecific fusion proteins which can bind to the NK receptor with one part and to tumour antigen with the other part. This work focuses on recombinant preparation of the NKp46 protein. To facilitate a study of the effects of O-glycosylation on the binding of the ligands, a mutation of the glycosylation site NKp46 T225A was prepared. A stably transfected HEK293S GnTI- and HEK293T cells had been prepared and these proteins were then extracellularly secreted. The Epa1 protein had been produced in E. coli bacterial expression system and purified. The binding ability of the Epa1 protein...
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Study of the role of N-glycosylation in function of anti-HER2 nanobody
Chytrá, Gabriela ; Vaněk, Ondřej (advisor) ; Černá, Věra (referee)
Cancer is currently widespread disease and its successful treatment requires the elimination of all cancer cells in the body. One method of cancer treatment is immunotherapy, which seeks to elicit an immune response and activate the body's anti-tumor defense mechanisms. Therapeutic antibodies are used to target tumor cells markers. One of such markers is the HER2 receptor which is overexpressed for example on the surface of breast cancer cells. Humanized monoclonal antibodies are often used as therapeutic antibodies, but other constructs such as bispecific particles, nanobodies or their analogs are also used. Nanobodies refer to recombinant antibody-derived variable domains that lack light chains in their structure. Such antibodies occur naturally, for example in camelid mammals or in certain cartilaginous fishes, such as sharks. This work describes the preparation of various glycoforms of the antiHER2 nanobody and verification of the effect of the glycosylation on the ability of nanobody to bind to the cell line that is overexpressing the HER2 receptor on its surface. A nanobody with complex natural glycosylation (produced in the HEK293T cell line) and a nanobody with uniform glycosylation (produced in the HEK293S GnTI- cell line) were prepared. The work also describes the cloning and production...
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Study of the interaction of receptor NKp46 with adhesin Epa1
Houserová, Jana ; Vaněk, Ondřej (advisor) ; Pavlíček, Jiří (referee)
One of the key components of the innate immune system are natural killer (NK) cells. The task of these cells is to induce apoptosis in target cells (e.g., cancer or virally infected cells). The target cells are identified by their interaction with surface receptors of the NK cells. On the surface of the NK cells, there are activating and inhibiting receptors. One of the activating receptors is the natural cytotoxicity receptor NKp46. Several ligands of this receptor have been identified, one of them being the epithelial adhesin Epa1 of yeast Candida glabrata. The invasive candidiasis caused by this yeast is a feared complication for patients with haematological diseases. The use of the NK cells in immunotherapy includes bispecific fusion proteins which can bind to the NK receptor with one part and to tumour antigen with the other part. This work focuses on recombinant preparation of the NKp46 protein. To facilitate a study of the effects of O-glycosylation on the binding of the ligands, a mutation of the glycosylation site NKp46 T225A was prepared. A stably transfected HEK293S GnTI- and HEK293T cells had been prepared and these proteins were then extracellularly secreted. The Epa1 protein had been produced in E. coli bacterial expression system and purified. The binding ability of the Epa1 protein...
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Preparation of fusion domains of human immunoreceptors for their utilization in immunotherapy
Cmunt, Denis ; Vaněk, Ondřej (advisor) ; Moserová, Michaela (referee)
The functions of the immune system include immunosurveillance of transformed cells, i.e., the ability to eliminate these cells before they become harmful to the organism. If the transformed cells succeed to escape the immune system surveillance, an oncological disease develops. The tumour immunotherapy aims to stimulate the immune system mechanisms to fight against the tumour. Lately, there's an interest in using NK cells in the immunotherapy of tumours. These cells appertain to the innate immune system and participate in immunosurveillance. When an NK cell encounters a target cell, its activation depends on the integration of signals from the surface activating and inhibiting receptors which bind ligands on the surface of the target cell. Upon activation, NK cell exhibits a cytotoxic response against the target cell. The use of NK cells in immunotherapy includes, among others, the testing of bispecific fusion proteins which can bind a tumour surface antigen by one part and NK cell activating receptor by the other part. Thus, these fusion proteins mediate a contact between both cells and trigger the cytotoxic response. This work presents a preparation of bispecific fusion proteins which consist of an activating ligand MICA (for the receptor NKG2D) or B7H6 (for the receptor NKp30), and a nanobody...
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