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The role of macrophages in immunosuppression mediated ny regulatory T cells
Kadlecová, Kristýna ; Holáň, Vladimír (advisor) ; Stříž, Ilja (referee)
Regulatory T cells (Treg) represent one of the most important mechanisms of immunoregulation. Treg suppress immune reactions and prevent overactivation of the immune system. There is a lot of ways of Treg action described, here we have focused on Treg interference with macrophages. The suppressor capacity of a highly purified Treg population was demonstrated in proliferation assays. The level of suppression of effector T cell proliferation differs depending on the presence of macrophages in the culture. Treg suppression has been significantly higher in the presence of macrophages. These observations led to hypotesis that Treg affect directly macrophages. However, using flow cytometry, reduction of expression of costimulatory molecules on macrophages after culture with Treg was not observed. Macrophages precultured with Treg showed a comparable functionality as macrophages cultured alone. Neither flow cytometry nor live cell imaging revealed any cytotoxic activity of Treg towards macrophages. Despite the presence of macrophages, Treg did not suppress effector cell proliferation in a model, where stronger activation of effector cells was induced. Therefore, a new hypothesis was presented - initially observed higher suppression in the presence of macrophages was probably caused by a qualitatively or...
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Depletion of Treg cells for potentiation of cancer treatment with HPMA copolymer-bound cytostatic drug conjugates"
Dvořáková, Barbora ; Kovář, Marek (advisor) ; Reiniš, Milan (referee)
Tumor diseases are severe problem worldwide with increasing number of patients suffering from various types of malignancies. Many of approved therapeutics cause serious side toxicities. Therefore, there are intensive efforts to improve cancer treatment protocols. The aim of this study was to deplete regulatory T (Treg) cells without affecting other immunocompetent cells playing a positive role in tumor eradication. Treg cells were reported to hamper anti-tumor immunity and promote tumor growth and survival. Thus, their selective elimination could lead to induction of anti-tumor responses and tumor rejection if combined with chemotherapy with selected N-(2- hydroxypropyl)methacrylamide (HPMA) copolymer-bound drug conjugates. Original approach was to deplete of Treg cells without the use of anti-CD25 mAb that has been widely exploited for Treg cell elimination; however, its long-term persistence in circulation together with inhibitory effect on activated effector cells (CD25+ ) are its main disadvantages. Thus, Treg cells were sensitized to cell cycle-specific cytostatic drugs via application of IL-2/anti-IL-2 JES6.1 mAb immunocomplexes that induce vigorous selective proliferation of this cell population. Subsequent application of cell cycle-specific cytostatics showed steep decrease of Treg cell...
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Markers of transplantation tolerance in kidney transplantation
Krepsová, Eva ; Viklický, Ondřej (advisor) ; Krejčí, Karel (referee) ; Živný, Jan (referee)
Long-term renal graft acceptance still requires long-term immunosuppressive therapy, which is accompanied by many adverse effects. Contrarily insufficient immunosuppression could lead to graft rejection and its failure. Therefore, research continues for biomarkers that reflect a patient's immunological status and thus allowing for individualized immunosuppressive therapy. In our study we showed lower incidence of acute rejection in kidney transplant recipients treated with rabbit anti-thymocyte globulin (rATG) or basiliximab induction within the first three months after transplantation. The rATG induction caused profound decrease of recipient's peripheral blood T and NK cells, as well as transcripts that are exclusively expressed by these cell types together with expansion of regulatory T cells (Tregs) among CD4+ T cells. In rATG group the increase of two transcripts associated with rejection (MAN1A1 and TLR5) was also observed in early post-transplant period. After the basiliximab induction we transiently detected CD4+CD25low/-FoxP3+ cell population along with disappearance of CD4+CD25+FoxP3+ Tregs. Basiliximab induction resulted in a transient increase in CD4+FoxP3+ Tregs, accompanied by the highest peripheral expression levels of markers associated with operational tolerance (FOXP3 and TCAIM)....
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Immunologic Characteristics of Cord Blood in Children with Increased Risk of Allergy Development Preventive Use of Probiotics
Hrdý, Jiří ; Prokešová, Ludmila (advisor) ; Tlaskalová - Hogenová, Helena (referee) ; Ulčová-Gallová, Zdeňka (referee)
Allergy is one of the most common diseases. Identification of early prognostic markers pointing to an increased risk of allergy development is therefore of increasing importance. Cord blood represents an easily attainable clinical material for searching for prognostic markers signalizing future allergy development. Proportions of Th1 cytokines, Th2 cytokines and regulatory cytokines were tested in cord blood of children of allergic mothers (children in relatively high risk of allergy development) in comparison with cord blood of children of healthy mothers (low risk children). Also the activities of lymphocytes, dendritic cells (DC) and regulatory cells (Tregs) were compared in children of healthy and allergic mothers. The generally increased activity of both in vitro stimulated and non-stimulated mononuclear cord blood leukocytes was proved in children of allergic mothers in comparison with low risk children. The increased activity of DC of high risk children was detectable only after polyclonal stimulation. Significantly less pronounced functional properties of cord blood Tregs were found in children of allergic mothers when compared with children of healthy mothers. The increased reactivity of lymphocytes and DC together with the decreased activity of Tregs can support an easier...
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Snižují regulační T lymfocyty riziko autoimmunity indukované CD8+ T lymfocyty?
Chadimová, Tereza ; Štěpánek, Ondřej (advisor) ; Šenolt, Ladislav (referee)
5 Regulatory T cells (Tregs) are essential for the maintenance of peripheral self-tolerance and prevention of autoimmunity by suppressing the response of self-reactive CD8+ and CD4+ T cells. However, while interactions of Tregs with CD4+ T cells have been extensively studied, their effect on the self-tolerance of CD8+ T cells has not been explored in detail. The main aim of this diploma project was to provide evidence whether and how Tregs prevent autoimmunity induced by CD8+ T cells. We used an experimental mouse model of autoimmune diabetes allowing us to acutely deplete Tregs and titrate the number of self-reactive T cells, self- antigen affinity, and self-antigen doses. We found out that Tregs play an important role in the prevention of CD8+ T-cell mediated autoimmunity. Moreover, we revealed that Tregs suppress both high-affinity T cells that escape negative selection and relatively weakly self-reactive, but numerous, positively selected T cells. Tregs do so by increasing requirement for the number of self-reactive CD8+ T cells required for the autoimmunity induction. Intriguingly, presence of Tregs does not impact threshold for self-antigen. Moreover, for the first time, we showed that Tregs can suppress CD8+ T-cell-mediated autoimmunity in the absence of conventional CD4+ T cells. This means that...
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Regulační T lymfocyty a nádorová onemocnění
SKALIČKOVÁ, Markéta
The main aim of this thesis was to study the role of regulatory T cells in cancer. Their presence, importance, and mechanism of their action were studied as well. The practical part was focused on reduction of bigger tumors and suppressing regulatory T-cell effects. The combination of TLR agonists, agonistic CD40 antibody and anti-CTLA-4 was studied on a mouse model of pancreatic adenocarcinoma.
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Markers of transplantation tolerance in kidney transplantation
Krepsová, Eva ; Viklický, Ondřej (advisor) ; Krejčí, Karel (referee) ; Živný, Jan (referee)
Long-term renal graft acceptance still requires long-term immunosuppressive therapy, which is accompanied by many adverse effects. Contrarily insufficient immunosuppression could lead to graft rejection and its failure. Therefore, research continues for biomarkers that reflect a patient's immunological status and thus allowing for individualized immunosuppressive therapy. In our study we showed lower incidence of acute rejection in kidney transplant recipients treated with rabbit anti-thymocyte globulin (rATG) or basiliximab induction within the first three months after transplantation. The rATG induction caused profound decrease of recipient's peripheral blood T and NK cells, as well as transcripts that are exclusively expressed by these cell types together with expansion of regulatory T cells (Tregs) among CD4+ T cells. In rATG group the increase of two transcripts associated with rejection (MAN1A1 and TLR5) was also observed in early post-transplant period. After the basiliximab induction we transiently detected CD4+CD25low/-FoxP3+ cell population along with disappearance of CD4+CD25+FoxP3+ Tregs. Basiliximab induction resulted in a transient increase in CD4+FoxP3+ Tregs, accompanied by the highest peripheral expression levels of markers associated with operational tolerance (FOXP3 and TCAIM)....
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Impact of the regulatory T cells detection and differences in expession of tumor antigens in ovarian cancer
Kloudová, Kamila ; Sojka, Luděk (advisor) ; Čáp, Michal (referee)
Regulatory T cells (Treg) play a key role in maintaining the immune tolerance. They suppress development of autoimmune diseases and contribute to maintaining the homeostasis of the immune system. Expansion and excessive ability of regulatory T cells to suppress the immune response is increasingly observed also at many types of cancer. Due to the active inhibition of the antitumor immune response Treg contribute to tumor progression. Specific phenotype based detection and analysis of Treg functional properties may contribute to the successful monitoring of Treg accounts and to the effective cancer immunotherapy itself. Tumor cells express high amounts of so-called tumor antigens, which may play a key role in the antitumor immune response. Expression level of the tumor antigens gives the evidence about relevancy of each antigen in the specific immune response and efficiency of cancer immunotherapy. These data are obviously important to be obtained from the tumor cell lines as well as primary tumor cells. In the first part of the thesis I was focusing on the quantitative analysis of regulatory T cells in tumor tissue and peripheral blood of patients with ovarian cancer. For this purpose I used the newly introduced methyl-sensitive quantitative PCR (MS-qPCR) method and compare the data with the widely...
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The role of the immune system in colorectal and ovarian cancer
Kocián, Petr ; Hoch, Jiří (advisor) ; Prausová, Jana (referee) ; Žaloudík, Jan (referee)
Prediction of clinical outcome in cancer is usually achieved by histopathological evaluation of tissue samples obtained during surgical resection of the primary tumor. Traditional tumor staging (AJCC/UICC-TNM classification) summarizes data on tumor burden (T), presence of cancer cells in draining and regional lymph nodes (N) and evidence for metastases (M). However, it is now recognized that clinical outcome cansignificantly vary among patients within the same stage. Data collected from largecohorts of human cancers has demonstrated the impact of immune-classification, which has a prognostic value that may add largely to the significance of the AJCC/UICC TNM-classification. In our study we examined the immune cells that infiltrated the tumor tissues of colorectal and ovarian cancer patients. In a cohort of newly diagnosed colorectal cancer patients we examined the correlations between the KRAS mutational status, patterns of tumor-infiltrating immune cells and the presence of tumor recurrence. Our data suggest that colorectal cancer patients with low levels of tumor-infiltrating lymphocytes, a high CD1a/DC-LAMP tumor-infiltrating dendritic cells ratio, and a KRAS mutation in codon 13 are at a high risk of disease recurrence. In ovarian cancer patients we focused on the dynamics of the tumor-infiltrating...
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Depletion of Treg cells for potentiation of cancer treatment with HPMA copolymer-bound cytostatic drug conjugates"
Dvořáková, Barbora ; Kovář, Marek (advisor) ; Reiniš, Milan (referee)
Tumor diseases are severe problem worldwide with increasing number of patients suffering from various types of malignancies. Many of approved therapeutics cause serious side toxicities. Therefore, there are intensive efforts to improve cancer treatment protocols. The aim of this study was to deplete regulatory T (Treg) cells without affecting other immunocompetent cells playing a positive role in tumor eradication. Treg cells were reported to hamper anti-tumor immunity and promote tumor growth and survival. Thus, their selective elimination could lead to induction of anti-tumor responses and tumor rejection if combined with chemotherapy with selected N-(2- hydroxypropyl)methacrylamide (HPMA) copolymer-bound drug conjugates. Original approach was to deplete of Treg cells without the use of anti-CD25 mAb that has been widely exploited for Treg cell elimination; however, its long-term persistence in circulation together with inhibitory effect on activated effector cells (CD25+ ) are its main disadvantages. Thus, Treg cells were sensitized to cell cycle-specific cytostatic drugs via application of IL-2/anti-IL-2 JES6.1 mAb immunocomplexes that induce vigorous selective proliferation of this cell population. Subsequent application of cell cycle-specific cytostatics showed steep decrease of Treg cell...
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