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Intrinsic factors in helper T-cells lineage choice
Andreyeva, Arina ; Neuwirth, Aleš (advisor) ; Chmelař, Jindřich (referee)
The process of clonal expansion of T lymphocytes, or T cells, belongs to the basic characteristics of adaptive immunity. A fundamental role in the immune response is played by the CD4+ T cells which are capable of evolving into the different subtypes (for example Th1 or Tfh) that help other types of cells to effectively eliminate pathogens. Each particular subtype activates different arms of the immune system for the most effective clearance of a particular pathogen. The way how the pathogen will be eliminated depends on the type of infection. This thesis aims to analyze relevant literature and known facts about factors that influence functional T-cell differentiation. This thesis will be mainly focused on the question of how much the T-cell receptor's structure or antigen affinity plays a role in this decision- making process. Another point of interest is the capability of T cells from one clone to produce different T helper cell subtypes, or they are preferentially biased towards a single differentiation pathway. Key words: adaptive immunity, CD4+ T cells, TCR, infections, differentiation
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Cellular and molecular mechanisms of naive T-cell priming
Kramářová, Ilona ; Musil, Jan (advisor) ; Pačes, Jan (referee)
T cell priming is a complicated signalling process involving several levels of molecular and spatiotemporal regulation. Whether TCR signalling is initiated depends on the TCR signalling threshold which is thought to be set during the T cell development in thymus by CD5 and CD6. TCR intrinsic downstream signalling ("Signal 1") involves several pathways which result in the production of the main proinflammatory transcription factors, namely NF-κB, NFAT and AP-1. Those transcription factors participate in the transcription of proinflammatory cytokines such as IL-2. The molecular interface of T cell priming involves signalling from several types of costimulatory receptors, namely CD28, CD27 and HVEM, which are allocated to the immunological synapse. A significant overlap is present between the downstream signalling networks of TCR and costimulatory molecules which amplifies the transcription of proinflammatory genes. Shortly after T cell priming, coinhibitory molecules, namely CTLA-4 and PD-1, are upregulated to deliver negative signals to tune the stimulatory signalling. The interplay between costimulatory and coinhibitory molecules represents "Signal 2" that is responsible for further progression of T cell signalling. Key words T cell priming, TCR signalling, T cell costimulation, T cell...
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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
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Chimeric antigen receptors in the treatment of hematological malignacies
Fellnerová, Adéla ; Filipp, Dominik (advisor) ; Černý, Jan (referee)
Chimeric antigen receptors (CARs) are artificial molecules composed of an antibody derived antigen recognition domain which is fused with the signal transduction domain derived from the physiological TCR. CAR technology used to transduce patients T-cells and endow them with the specificity to a certain surface antigen, has been a major breakthrough in cancer immunotherapy in the last decade. This strategy has been most successful for treating hematologic malignancies. Various CAR approaches and applications are currently tested mainly in the United States where many clinical trials have been launched. In contrast, in the Czech Republic, there are only a few teams focused on this topic with no clinical trials going on. During my work on this diploma thesis and in close collaboration with MUDr. Pavel Otáhal, PhD., who is working on implementation of CAR technology into the Czech clinics for the treatment of B-cell malignancies, individual functional CARs were prepared and tested. CAR expressing Jurkat T-cell lines were generated using a lentiviral vector transduction system. CAR functionality was determined by two different assays. We have shown that individual CARs are able to recognize the B-cell lineage specific antigens CD19 and CD20 and significantly up-regulate the activation molecule CD69 upon...
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