|
|
Heterogeneity of antigen-presenting cells in the thymus and its relevance for the establishment of central tolerance
Sýkora, Vojtěch ; Filipp, Dominik (advisor) ; Černý, Jan (referee)
The crucial function of the thymus is the establishment of central tolerance. In this process, developing T-cells are tested for their self-reactivity, since self-reactive T-cells might cause the autoimmunity if they would escape from the thymus to the periphery. Many thymic antigen-presenting cells are essential for establishment of central tolerance. Their role is to present self-antigens to the developing T-cells. Such presentation is capable to reveal the self-reactive potential of T-cells which can be then directly removed or deviated into suppressive T-regulatory cells. In the last several years, a high level of heterogeneity has been described among the thymic antigen-presenting cells and the molecular mechanisms that govern their functions towards enforcement of tolerance began to be uncovered. This thesis summarises recent knowledge in the field of heterogeneity of the thymic antigen-presenting cells and its relevance for establishment of the central tolerance, with the major focus on conventional dendritic cells and post-AIRE medullary thymic epithelial cells. This thesis also outlines recent advances in understanding of functional mechanisms and regulations of maturation of the antigen-presenting cells.
|
|
|
Metodické přístupy k vyšetření lymfoidních tkání jeseterů
ŠÁLKOVÁ, Eva
We present material, data and results that were encountered in doctoral study and summarized in dissertation thesis. Our research was focused on methodical approaches to examination of lymphoid tissues in sturgeons. Sturgeons live on Earth for a long period of time. Well-developed immune system enabled sturgeons to face and deal with different attacks, and thus played an important and crucial role in sturgeon survival until present days. Sturgeons exhibit large genomes among fishes and are well known for their polyploidy origin. Acipenseriformes have a high tolerance for hybridization as well as for spontaneous doubling of chromosome sets. In their evolution, at least three independent polyploidization events have taken place, in the literature known as 3R hypothesis (three rounds hypothesis). Therefore, the present research focused on the haematopoietic and lymphoid tissues examination. Representatives of different ploidy level groups were encountered in the study: sterlet (Acipenser ruthenus) represented diploid (2n) group, Russian sturgeon (Acipenser gueldenstaedtii) was chosen as tetraploid group representative (4n), and finally shortnose sturgeon (Acipenser brevirostrum) served as hexaploid group representative (6n). Haematopoietic and lymphoid tissues were conventionally histologically processed, obtained sections were stained using haematoxylin and eosin. Advanced histological staining methods were applied when examining tissues to map and recognize particular cell types involved in haemato- and lymphopoiesis. Hassall's corpuscles were detected in thymi, particular in the thymic medulla; to our knowledge, it was the first description of Hassall's corpuscles in sturgeons. Subsequently, the thymus of juvenile sterlet (Acipenser ruthenus) was examined immunohistochemically. The wide range cytokeratin, vimentin, S-100 protein, leukocyte common antigen LCA (CD45) and CD3 were selected as the markers to map the thymic microenvironment. Commercially available human antibodies were applied on fish tissue, and wide range cytokeratin, vimentin, S-100 protein brought conclusive results and distinguished nature of different microenvironmental components. Contrarily, LCA and CD3 application was negative or inconclusive, and failed. Study confirmed the possibility of human antibody application on fish tissue, together with the need to generate fish and species specific antibodies, mostly when examining lymphoid tissues. Except for the histological and immunohistochemical examination, respectively, the lymphoid or immune system should be tested when using the determination of white blood cell parameters. Generally, the blood is more easily accessible (vessel puncture), and the determination of the total number of leukocytes and the differential counts represent important fish health and physiology status. Under the study, representatives of three different ploidy level groups were tested and white blood cell parameters were monitored monthly during a period of one year. Data suggested the significant effect of ploidy level on total number of leukocytes and morphological nuclear changes in granulocytes and lymphocytes. Annual variation in differential leukocyte counts depended on the species and influence of various external conditions rather than ploidy level. Examination of white blood cell parameters (total number of leukocyte and differential count), as well as histological and immunohistochemical examination, respectively, represent the main methodical approaches for lymphoid organs and immune system assessment in sturgeons. Methods should be applied in an ichthyological practise. Obtained results contribute to fish health status evaluation.
|
|
|
Adaptive immune system in patients with primary immunodeficiencies
Klocperk, Adam ; Šedivá, Anna (advisor) ; Filipp, Dominik (referee) ; Litzman, Jiří (referee)
(ENG) This thesis summarizes the results of a project dedicated to adaptive immune system of patients with partial DiGeorge syndrome caused by deletion of 22q11.2. The introduction sets the DiGeorge syndrome into a broader context of international pathophysio- clinical classification of primary immunodeficiencies and goes into detail describing its history, causes, clinical phenotype, therapeutic options and changes of the immune system. The attached manuscripts illustrate the premature aging of the T cell population, but also impaired development of B cells with low class-switched memory and high naïve subpopulations, along with high serum levels of BAFF, a B cell survival factor. The surprising lack of T independent marginal zone- like (MZ-like) B cells is reflected in decreased natural anti-α-Gal antibodies. The faulty B cell maturation and imperfect germinal center response is not caused by a deficit of follicular helper T cells, which are in fact increased in DiGeorge syndrome patients, and in most cases doesn't lead to hypogammaglobulinaemia. Despite the high incidence of autoimmune disease, in particular thyroiditis and thrombocytopenia, and a trend towards hypergammaglobulinaemia in adolescence and adulthood, we saw normal proportion of regulatory T cells (Tregs) and normal expression of...
|
|
|
AIRE-expressing cells in immune tolerance in health and disease
Vobořil, Matouš ; Filipp, Dominik (advisor) ; Černý, Jan (referee) ; Ehrlich, Lauren Ilyse Richie (referee)
The process of self-nonself discrimination by the immune system is a fundamental attribute of healthy organisms. Since T-cell receptors (TCRs) are generated by the random process of somatic recombination without regard to its targets, the newly developed T-cell clones could recognize either self or nonself antigens. The mechanisms of central tolerance robustly limit the self-reactive repertoire within the T-cell population via deletion of clones that express self-reactive TCRs or their deviation into the regulatory T-cells (Tregs). These processes occur mainly in the thymic medulla where the TCR reactivity to self-antigens is tested by various types of antigen-presenting cells, mainly medullary thymic epithelial cells (mTECs), dendritic cells (DCs), and B-cells. The cooperation between these cell-types has been shown to be essential for the establishment of thymic tolerance. A key molecule regulating the production of self-antigens is the autoimmune regulator (AIRE), which is thought to be expressed primarily by mTECs and its mutations are associated with the development of severe autoimmune disorders. In this context, the presented thesis describes the novel regulatory pathways important for the development of a functional and "harmless" repertoire of T-cells and for enforcement of tolerance....
|
|
|
Adaptive immune system in patients with primary immunodeficiencies
Klocperk, Adam ; Šedivá, Anna (advisor) ; Filipp, Dominik (referee) ; Litzman, Jiří (referee)
(ENG) This thesis summarizes the results of a project dedicated to adaptive immune system of patients with partial DiGeorge syndrome caused by deletion of 22q11.2. The introduction sets the DiGeorge syndrome into a broader context of international pathophysio- clinical classification of primary immunodeficiencies and goes into detail describing its history, causes, clinical phenotype, therapeutic options and changes of the immune system. The attached manuscripts illustrate the premature aging of the T cell population, but also impaired development of B cells with low class-switched memory and high naïve subpopulations, along with high serum levels of BAFF, a B cell survival factor. The surprising lack of T independent marginal zone- like (MZ-like) B cells is reflected in decreased natural anti-α-Gal antibodies. The faulty B cell maturation and imperfect germinal center response is not caused by a deficit of follicular helper T cells, which are in fact increased in DiGeorge syndrome patients, and in most cases doesn't lead to hypogammaglobulinaemia. Despite the high incidence of autoimmune disease, in particular thyroiditis and thrombocytopenia, and a trend towards hypergammaglobulinaemia in adolescence and adulthood, we saw normal proportion of regulatory T cells (Tregs) and normal expression of...
|
|
|
The role of NF-kappa B signaling in establishment of central tolerance
Březina, Jiří ; Filipp, Dominik (advisor) ; Černý, Jan (referee)
Ce trál í tolera e, která je usta ove a v th u, výz a ě redukuje repertoár reaktiv í h T l fo tů a tí u ožňuje před házet rozvoji autoi u it í h o e o ě í. ez t ý Autoi u it í regulá Aire , který je e pri ova ý ikát í i edulár í i epiteliál í i uňka i řídí pro iskuit í ge ovou e presi tisí ů tkáňově spe ifi ký h a tige ů, která je zásad í pro úči ou egativ í selek reaktiv í h T l fo tů regulač í h l fo tů. Výzku posled í h dvou dekád sta ove í e trál í tolera e. této prá i předkládá ejdůležitější poz atk dokládají í její klíčovou roli ve vývoji u ěk pří é regula i ge ové e které hovoří ve prospě h edo e ě é skuteč ost , že hlav í regulátore pro esů podílejí í h se a vý , udržová í a fu k i e trál í tolera e Klíčová slova: Centrální tolerance, NF
|
|
| |
|
|
Emerging role of Toll-like receptors in central tolerance
Súkeníková, Lenka ; Filipp, Dominik (advisor) ; Černý, Jan (referee)
Medullary thymic epithelial cells (mTECs) provide a specific thymic microenvironment for the processes associated with T cell development. Their irreplaceable function is the expression of specific set of antigens which are expressed only in peripheral tissues, called tissue restricted antigens (TRAs). Such expression, often referred to as promiscuous, was originally described with the discovery of transcriptional regulator Aire. Aire, which has a potential to interact with many other transcription factors, also binds to DNA, and thus can alter the general pattern of cellular gene expression. T cells exhibiting a strong affinity to TRAs expressed on mTECs are removed from the thymus by negative selection or their development is deviated to regulatory T cell (Treg) lineage. Studies on mice and humans confirmed the critical role of Aire protein in the establishment of the central tolerance. Inactivating mutations in Aire gene cause deficiency in TRA expression, failure to remove and the escape of self-specific T cells from the thymus to periphery, and in turn, autoimmunity. Experimental evidence points to the key role of NF-κB signaling pathway in mTECs development. The very same pathway is regulated also by Toll-like receptors (TLRs), which recognize evolutionary conserved structures derived from...
|
|
|
Role cytokinů ve vývoji a diferenciaci regulačních T buněk
Procházková, Jana ; Holáň, Vladimír (advisor) ; Kovář, Marek (referee) ; Stříž, Ilja (referee)
The development and function of T helper (Th) cells and regulatory T cells (Tregs) are plastic processes that are regulated by cytokines. In our project we first analyzed the effect of different cytokines on the development of induced (i) Tregs. It has been demonstrated that iTregs arise from CD4+ CD25- T cells upon stimulation with alloantigen in the presence of transforming growth factor β (TGF-β). The development of these Tregs and their proliferation were inhibited by interleukin (IL)-4 and IL-12. The aquired results also demonstrated distinct responses of naturally occuring (n) Tregs and iTregs to the regulatory action of IL-4 and an opposite role of IL-4 in maintenance of nTregs and iTregs phenotype. An important role in the induction of T cell subsets may play also mesenchymal stem cells (MSCs) which can, under specific conditions, produce TGF-β and IL-6. Depending on the current production of TGF-β or IL-6, MSCs can qualitatively regulate the ration between Tregs and Th17 cells. Anti-inflammatory Tregs and pro-inflammatory Th17 cells are induced upon stimulation in the presence of TGF-β and TGF-β and IL-6, respectively. In addition to our previous work we studied the role of IL-12 in the development of Tregs and Th17 cells. It was shown that Treg and also Th17 cell differentiation was...
|
|
|
Hereditary immunological diseases in dogs
KREJČOVÁ, Lenka
This thesis summarizes the most important findings of primary immunodeficiencies in different breeds of dogs, their genetic background, symptoms, their treatment options: canine leukocyte adhesion deficiency, trapped neutrophil syndrome, Pelger-Huet anomaly, severe combined immunodeficiency, grey collies syndrome, selective IgA deficiency, complement C3 deficiency and growth hormone deficiency with hypoplastic thymus in dogs. This diseases, often with autosomal recessive inheritance, are for affected individuals usually fatal. Research of primary immunodeficiencies in dogs is substantial also because it often serves as a model for similar studies human deficiencies.
|
guest ::
