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Characterization of T-cell clones from naïve and virtual memory compartment
Přibíková, Michaela ; Štěpánek, Ondřej (advisor) ; Drbal, Karel (referee)
Virtual memory (VM) CD8+ T cells represent a population of antigen-inexperienced T cells with an apparent memory phenotype. In lymphoreplete germ-free mice VM CD8+ T cells represent 10-20% of all peripheral CD8+ T cells. Their origin correlates with the levels of self-reactivity where the main factor that determinates the T-cell fate decision is the strength of homeostatic signals. In the first part of this thesis, we demonstrated that VM CD8+ T cells and naïve CD8+ T cells had distinct TCR repertoire and T-cell subsets contained different clonotypes. Moreover, 'VM clones' were enriched among VM T cells and were also present in naïve T cells. In contrast, 'naïve clones' were almost exclusively detected in naïve T cells. Next, we characterized the signaling of particular OVA-reactive TCRs from both naïve and VM subsets. We confirmed that 6 out of 8 tested TCRs were responsive to Kb-OVA. In the last part of the thesis, we developed and optimized a qPCR-based method for the relative quantification of specific T-cell clonotypes prior to and during the immune response. This method will serve as a tool for studying the biology of particular VM and naïve T-cell subsets and their role during the immune response. Keywords: T-cell receptor, homeostatic signaling, self-reactivity, virtual memory cells, T cells
Fibroblast activation protein and local immunosuppression in glioblastoma
Ternerová, Nikola ; Stollinová Šromová, Lucie (advisor) ; Drbal, Karel (referee)
Glioblastoma multiforme (GBM) is the most aggressive type of primary brain tumor. Current treatment includes surgical resection with following radio/chemotherapy, but prognosis of patients remains poor with median survival only about 15 months. GBM is characteristic for necrotic regions, abnormal vascularization and strong immunosuppression. Dynamic interactions of cancer cells, immune cells and other stromal cells in the tumor microenvironment can promote tumor growth and progression. Fibroblast activation protein α (FAP) is overexpressed by the cells in tumor tissue. FAP is important in angiogenesis, remodelation of extracellular matrix and immunomodulation in cancers. The role of FAP in the tumor microenvironment is the subject of recent research. The aim of the thesis was to prepare a syngeneic mouse model of glioblastoma with and without FAP expression, implement and optimalize the dissociation method for GBM tumor tissue and detect a variety of infiltrated immune cell populations in the GBM microenvironment by flow cytometry. Optimization of dissociation protocol for glioblastoma tissue was a crucial step for viable cell suspension required for cytometry study of immune cell populations. A combination of dissection by dissociator and enzymatic digestion with mild enzymes was found to be the...
Genomic instability in patient tumors due to excesive AID activity
Vaníčková, Karolína ; Drbal, Karel (advisor) ; Macůrek, Libor (referee)
AID is a member of APOBEC family of mutational enzymes. AID generates U:G mismatches in ssDNA by deaminating cytosine to uracil. In B cells error-prone repair of these mismatches induces a mutational burden in the process of somatic hypermutation of Ig locus during affinity maturation of immunoglobulins (Ig). AID also induces double-strand breaks during Ig class switch recombination or primary Ig diversification through templated gene conversion in some vertebrate species. AID might gain tumorigenic potential in case of insufficient regulation of induction and repair processes, causing genomic instability and possibly leading to tumorigenesis. AID is induced in epithelial tissues by proinflammatory cytokines via canonical NF-B pathway. Both exogenous factors (pathogens Helicobacter pylori or HCV), endogenous factors (bile acid) or even physiological state such as ovulation are the initiating factors. Thus, AID might be the link between inflammation and carcinogenesis. AID is expressed in different stages of carcinomas, mostly during the initial oncogenic transformation. Mice with ectopic AID expression develop lung, gastric, oral and hepatic carcinomas as well as melanomas. AID also regulates epithelial-mesenchymal transition in other tumors. AID is responsible for treatment resistance in both CML...
Tumor in vitro chemosensitivity and resistance assays (CSRA) using flow cytometry
Drozdová, Tereza ; Drbal, Karel (advisor) ; Balounová, Jana (referee)
In vitro chemosensitivity and resistance assay determine the sensitivity of a specific tumor after a specific treatment administration in an experimental setup. A heterogeneous population of cancer cells is exposed to various approved anticancer drugs in short-term ex vivo and their combination thereof. The effect of each drug is then determined based on the viability of specific tumor cells allowing for individual patient treatment using a precise combination of drugs. This approach is an example of the personalized medicine principle, which is focusing on the adjustment of diagnostic procedures and treatment of a specific patient. Therefore, its goal is to avoid treatment failure in patients with poor response to the statistically most effective treatments based on randomized clinical trials. The number of viable cells determined by the flow cytometry provides very accurate statistics for multiparametric analysis. A necessary prerequisite is the presence of dissociated cancer cells in a single cell suspension. This is different from cloning methods, where tumor colonies grow on agar media, or from histocultures, which are specific with its three-dimensional tissue cultivation. We can also sort cells from suspension based on their pre-defined attributes for their subsequent functional testing. The...
Effects of the Interferon regulatory factor 3 on immune responses to vaccinia virus in the atopic organism
Pilná, Hana ; Mělková, Zora (advisor) ; Drbal, Karel (referee)
Vaccinia virus (VACV) is an enveloped DNA virus, member of the Orthopoxviridae genus. VACV genome size is about 200 kbp. This huge genome capacity allows VACV to encode a set of factors that are non-essential for virus replication and spread in vitro. While these factors are needed for interfering with host immune responses, VACV remains strongly immunogenic. Cell-mediated and humoral immune responses in atopic disorders are deregulated to a certain extent, leading to complications in case of infection or vaccination with vaccines based on replicating viruses, such as eczema vaccinatum caused by VACV. VACV effects on immune responses consist among others in the inhibition of expression of type I interferon (IFN) at various levels - for example in a specific inhibition of phosphorylation of the interferon regulatory factor-3 (IRF-3) via inhibition of the activity of TANK-binding kinase 1 (TBK 1) that normally phosphorylates IRF-3. Phosphorylation allows IRF-3 to translocate into the nucleus where it initiates transcription of IFNβ followed by induction of expression of IFN and interferon stimulated genes. Expression of these genes is shut down when IRF-3 activity is inhibited. To overcome this block, a recombinant VACV expressing murine IRF-3 under VACV p7.5 promotor (WR-IRF3) was generated....
Cytometric assay of antigen-specific T cell response in monitoring of BCG vaccine therapy
Hadlová, Petra ; Drbal, Karel (advisor) ; Kalina, Tomáš (referee)
Bladder carcinoma (BCa) is among the most common carcinomas in the Western world. Despite the availability of effective therapies, there is currently an urgent need to develop a stratification method, which would enable the accurate identification of patients responsive to therapy. In the theoretical part of my diploma project I describe the heterogeneity of BCa and the currently applied immunotherapeutic approaches. I specifically focused on the Bacillus Calmette-Guérin (BCG) vaccine instillation. For decades another use of BCG has been a prophylactic vaccination against tuberculosis (TB) infection. BCG serves as a model treatment because it is highly efficient when prescribed to the responsive patient. However, an effective stratification is yet to be developed for BCa and latent tuberculosis infection (LTBI) diagnosis and/or monitoring. In the experimental part of my project, I developed and tested a 10-parameter panel for T cell- specific activation test (TAT) applicable for a stratification of BCa patients as well as for the detection of LTBI. I tested the panel on positive controls using flow cytometry (FCM) method because it allows for detection and measurement of dozens of markers at a single cell level. It is easily applicable to available urine and blood samples obtained from BCa...
Activation and regulation of cell death in senescent cancer cells.
Holíček, Peter ; Anděra, Ladislav (advisor) ; Drbal, Karel (referee)
Cellular senescence is a distinct cell state, characteristic by cessation of cell proliferation and it is accompanied by specific morphological and biochemical alterations. Increasing and persisting incidence of senescence cells has been shown to have detrimental effect on an organism largely contributing to its ageing. Senescent cells also positively support tumour growth and can even stimulate carcinogenic transformation of surrounding cells. Moreover, senescence can be induced even in tumour cells spontaneously or by chemotherapy. Regardless of an initial stimuli and type of cells, there are two main senescence inducing pathways p16/pRb and p53/p21. Both senescent cells as well as senescent cancer cells seems to have modified apoptotic signalling at the level of mitochondria and Bcl-2 family proteins. In this study, we aimed to analyse effect of senescent state as well as pre-senescent (growth arrested state) induced by p16/pRb and p53/p21 signalling pathways on the response of H28 mesothelioma cancer cells-derived clonal cultures to various cell death-inducing stimuli. By inducible expression of p16 and p21 proteins in doxycycline-dependent manner, we forced cells to acquire senescent-like phenotype, which we detailly characterised. Our results showed that senescent-like phenotype, manifests...
Immunogenicity of induced pluripotent stem cells (iPSC)
Tejklová, Tereza ; Drbal, Karel (advisor) ; Hájková, Michaela (referee)
Ectopic expression of several transcription factors into the somatic cells allows us to artificially dedifferentiate them into induced pluripotent stem cells (iPSC), which show great promise in regenerative medicine and personalized disease modelling, as well as diagnostic tools. Unique attribute of iPSC is the possibility of creating autologous cells for each patient, which could be used for transplantation without fear of immune rejection. However, cells differentiated from iPSC generally display decreased expression of MHC I glycoproteins, which leads to the activation of NK cells of innate immunity. T cells, the part of adaptive immunity, are activated after recognition of antigen peptide or foreign MHC I glycoproteins only in co-operation with costimulatory molecules, which are not usually expressed on iPSC. During dedifferentiation, cells keep the epigenetic profile of the source cell, which can result in the abnormal expression of genes within derived cell lines. Overall immunogenicity depends on the method of iPSC preparation, with respect to genomic stability. Another important factor is the immune environment of transplantation site as well as the tissue damage caused during transplantation. This results in the presentation of danger signals (DAMPs), which are then recognized by pattern...
Immunogenic cell death
Šímová, Michaela ; Drbal, Karel (advisor) ; Javorková, Eliška (referee)
According to the danger model, the immune system is activated by endogenous molecules known as danger-associated molecular patterns (DAMP) that are externalized from the interior of a dying cell to the cell surface or released into the extracellular space. Due to the loss of plasma membrane integrity a necrotic cell death as well as several types of proinflammatory programmed cell death are considered to be immunogenic, whereas apoptosis, on contrary, has been initially defined as a tolerogenic type of cell death. However, under certain circumstances, the immune response can be initiated by an apoptotic cell after exnternalization of DAMP molecules by newly described secretory pathways. This phenomenon was observed on tumor cells as a result of some widely used therapeutic modalities and is known as immunogenic cell death (ICD). Nomenclature of selected types of cell death is part of this thesis. The aim of this bachelor thesis is to provide an evidence of the experimental support for ICD theory during in vivo initiation of the immune response. I will evaluate the correlation between ICD and the induced exposure of DAMP molecules on the surface of tumor cells or their secretion to the extracellular space.
Microvesicle and exosome detection in immune-related diseases
Šťastná, Evelína ; Drbal, Karel (advisor) ; Fabišik, Matej (referee)
Exosomes (ES) and microvesicles (MV), collectively called extracellular vesicles (EV), are submicroscopic vesicles encapsulated by a phospholipid bilayer. Smaller ES (40 - 100 nm) originate in endosomal compartment, while larger MV (50 - 1000 nm) shed from cell plasma membrane. EV are secreted by all types of cells. They consist of lipids and proteins, but their composition varies according to the cell they originate from. In addition, they differ in the cargo they transport (DNA, RNA and proteins). They occur in every bodily fluid in much higher amounts compared to the original cells themselves, what makes them an attractive and accessible biomarker of autoimmunity diseases, cardiovascular diseases or tumours. For detection of EV, sensitive flow cytometry (FCM) is used, which I am going to compare to alternative methodologies. Part of this work will be description of EV biogenesis and then I will focus on the role of EV in coagulation and inflammation related to autoimmune diseases, more specifically in rheumatoid arthritis (RA).

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