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Spontaneous Regression of Melanoma in Pigs of the MeLiM Strain
Plánská, Daniela
Melanoma is a skin tumour arising from melanocytes - skin cells bearing pigment melanin. Melanoma belongs among immunogenic tumours, which is probably associated with a relatively high incidence of partial spontaneous regression (SR). Melanoma-bearing Libechov Minipigs (MeLiM) represent a specially bred animal model that is mostly affected by nodular melanomas, which fully regressed in about 2/3 of the affected animals. Our interest was to examine immune response (associated with melanoma cell destruction) and the role of proteins related to the extracellular matrix (reflecting tissue remodeling) during SR of MeLiM melanoma. We performed an extensive time-lapse study of skin melanomas taken from individuals of the MeLiM strain at 3, 4, 6, 8, 10, 12, 20 and 32 weeks (5-10 samples in each age category) in which we immunohistochemically detected the expression of collagen IV, laminin, fibronectin, tenascin C, as well as MMP-2 and we monitored the proportion of basic immune subpopulations in blood and tumour by flow cytometry. The higher expression of collagen IV, laminin and MMP-2 positively correlated with the appearance of melanoma cells. The expression of collagen IV and laminin indicates a possible survival of tumour cells due to the interaction with these proteins, the presence of MMP-2 in these...
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Novel methods of treatment of B cell malignancies based on immunotherapy with genetically modified T cells
Novotná, Natálie ; Otáhal, Pavel (advisor) ; Šmahel, Michal (referee)
CAR T cell therapy represents a promising method in treatment of hematological malignancies. Gene immunotherapy uses modified T cells that express a chimeric antigen receptor (CAR) on their surface. Modified T lymphocytes are able to recognize and destroy target cells based on specific surface markers. Although CAR T cell therapy is used in clinical practice, there is a number of limitations that reduce its effectiveness. The aim of this thesis is to explore new possibilities of making the entire therapy more efficient through endogenous secretion of interleukins (IL-7, IL-15, IL-21) under the control of inducible promoters, and thus to strengthen the persistence and expansion of CAR T cells in vivo. For this purpose, inducible expression systems containing the gene for CAR19 receptor specifically recognizing the CD19 molecule and the interleukin gene located under inducible NFAT or NR4A promoters, were constructed. The assembled vectors were electroporated into PBMC cells using the PiggyBac transposon system to achieve stable expression in T lymphocytes. After co-cultivation with RAMOS cell line, data were obtained by measurement on a flow cytometer and the ELISA method. Based on the results, it is evident that stimulated CAR T cells are able to generate higher concentrations of interleukins,...
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Mechanisms of antigen presentation in the etiopathogenesis of celiac disease
Hudec, Michael ; Černá, Marie (advisor) ; Hrdý, Jiří (referee) ; Slavčev, Antonij (referee)
1 ABSTRACT Celiac disease (CeD) is a chronic autoimmune disease that develops as a response of the immune system to the presence of gluten in the small intestine. CeD is manifested not only by classic intestinal symptoms: abdominal pain, constipation or diarrhea, as well as complex less common symptoms: anemia, osteoporosis, psychiatric disorders or menstrual cycle disorders. HLA risk alleles predisposing to origin of celiac disease are HLA-DQ2 (DQA1*05:01 / DQB1*02:01) and HLA-DQ8 (DQA1*03:01 / DQB1*03:02). There are other celiac disease-associated polymorphisms outside of HLA locus (6p21.3) that are located in 5q32 and 19p13 regions with unclear connection to CeD development. HLA class II glycoproteins are expressed on antigen presenting cells (APC) that include dendritic cells, macrophages and B cells. Monocytes are one of several possible dendritic cell precursors that circulate in the bloodstream. Deviations in the frequency of intermediate monocytes are directly associated with autoimmune disorders such as Crohn's disease or rheumatoid arthritis. It is known that the monocytes of CeD patients show pro-inflammatory reaction in the presence of gluten. It means that, in the context of CeD, the response to gluten arises earlier than the activation of gluten-specific T cells. The conventional way of direct...
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The role of the interaction of LCK with CD4/CD8 coreceptors
Cesneková, Michaela ; Štěpánek, Ondřej (advisor) ; Černý, Jan (referee)
LCK kinase is an essential regulator of T-cell signalling that interacts with CD4 and CD8 coreceptors, which are crucial for T-cell development and T-cell lineage commitment. Their role, as well as the role of their interaction with LCK in the peripheral T cells, remains disputable, despite being studied for decades. This thesis aims to investigate the importance of LCK-coreceptor interaction in CD8+ T cell signalling and development and to determine the significance of the serine residues in LCK-mediated CD4 endocytosis. We used LCK variants bearing mutations of the coreceptor binding site or its catalytic domain in both mice and cell lines to solve this perplexity. First, the enzymatic activity of LCK variants was evaluated in this thesis. Second, we demonstrate that the function of CD8 is both, LCK-CD8 interaction dependent and independent. Then we examined the late stage of CD8+ T cell development, showing that the absence of the interaction has very mild consequences. It affects only the response of post- selection CD8 single-positive, but not double-positive, thymocytes to sub-optimal antigenic stimulation. Finally, we observed that CD4 with the mutation of all three intracellular serines to alanines shows similar LCK-dependency as wild type CD4. Overall, this study sheds light on the...
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Spontaneous Regression of Melanoma in Pigs of the MeLiM Strain
Plánská, Daniela ; Horák, Vratislav (advisor) ; Smetana, Karel (referee) ; Bartůňková, Jiřina (referee)
Melanoma is a skin tumour arising from melanocytes - skin cells bearing pigment melanin. Melanoma belongs among immunogenic tumours, which is probably associated with a relatively high incidence of partial spontaneous regression (SR). Melanoma-bearing Libechov Minipigs (MeLiM) represent a specially bred animal model that is mostly affected by nodular melanomas, which fully regressed in about 2/3 of the affected animals. Our interest was to examine immune response (associated with melanoma cell destruction) and the role of proteins related to the extracellular matrix (reflecting tissue remodeling) during SR of MeLiM melanoma. We performed an extensive time-lapse study of skin melanomas taken from individuals of the MeLiM strain at 3, 4, 6, 8, 10, 12, 20 and 32 weeks (5-10 samples in each age category) in which we immunohistochemically detected the expression of collagen IV, laminin, fibronectin, tenascin C, as well as MMP-2 and we monitored the proportion of basic immune subpopulations in blood and tumour by flow cytometry. The higher expression of collagen IV, laminin and MMP-2 positively correlated with the appearance of melanoma cells. The expression of collagen IV and laminin indicates a possible survival of tumour cells due to the interaction with these proteins, the presence of MMP-2 in these...
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Roles of antigen presenting cells in regulation of Th17 response against Candida albicans
Böhmová, Helena ; Dobeš, Jan (advisor) ; Kostovčíková, Klára (referee)
Candida albicans is a common human pathobiont that inhabits mucosal surfaces throughout the body. In healthy individuals, it behaves as a benign member of the microfora. However, in immunocompromised individuals Candida becomes pathogenic and causes extensive mucosal infections. In the most severe cases, Candida translocates into the bloodstream and causes life-threatening deep tissue infections. Although the innate immune components involved in early anti-Candida immune response are relatively well defned, our knowledge regarding adaptive T cell responses to Candida is limited. Several populations of antigen-presenting cells (APCs) have been implicated in the induction of protective Th17 response against Candida - including innate lymphoid cells type 3 (ILC3s), conventional dendritic cells (cDCs) and CX3CR1+ mononuclear phagocytes (MNPs). The cellular and molecular mechanisms by which Candida-specifc T cells are induced have not yet completely been identifed. Presented thesis focuses on the involvement of direct antigen presentation by these APC populations in mounting the anti-Candida adaptive immune response. Furthermore, this is investigated in the context of both gastrointestinal colonization and bloodstream infection by C. albicans. In the frst part, published data concerning the immune...
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In vitro modulation of immune cells for adoptive cellular cancer immunotherapy
Kalkušová, Kateřina ; Smrž, Daniel (advisor) ; Kverka, Miloslav (referee)
Cancer is one of the leading causes of death in developed countries. Its traditional treatment is based on surgical removal of the tumor and metastases, radiotherapy, and chemotherapy. Recently, many new therapy options, including immunotherapy, have been investigated. Cancer immunotherapy seems to be a very promising treatment option as it has experienced many successes in the last few decades. However, there is still a number of patients not responding to today's immunotherapy methods. Adoptive cellular immunotherapy is one of those immunotherapeutic methods. This immunotherapeutic modality uses ex vivo prepared immune cells that participate in anti-tumor responses. Nowadays, most research is focused on the use of T cells, although many other cell types are considered, including dendritic cells. This thesis is focused on the modulation of dendritic cells for adoptive cellular cancer immunotherapy. The aim of the practical part is to evaluate the influence of beta2-microglobulin on the maturation of monocyte-derived dendritic cells. Key words: Adoptive cellular immunotherapy, dendritic cells, beta2-microglobulin, cancer
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Mechanisms of the tolerance and homeostasis of immune cells
Tsyklauri, Oksana ; Štěpánek, Ondřej (advisor) ; Černý, Jan (referee) ; Froňková, Eva (referee)
The ability of the immune system to tolerate self-antigens while mounting appropriate responses to pathogens is indispensable for the survival of the organism. Despite years of research, many details of the mechanisms of self-tolerance are still not well understood. The objective of this thesis is to extend our knowledge of the mechanisms of immune tolerance. The core of the PhD thesis consists of five publications related to two main research directions. The first one addresses the mechanisms of peripheral immune tolerance established by regulatory T cells (Tregs). We showed that Tregs increase the quorum of self-reactive CD8+ T cells required for the induction of autoimmunity. In addition, we identified a novel subset of antigen-stimulated CD8+ T cells, which expand in the absence of Tregs. We called them super-effector T cells. We revealed that the administration of IL-2 phenocopies the absence of Tregs, i.e., it induces super- effector T cells, and enhances CD8+ T cell response in autoimmunity and cancer. Our results provide strong evidence that the major suppressive mechanism of Tregs is limiting IL-2 availability for CD8+ T cells. Furthermore, in a collaborative project, we have shown that MyD88 signaling in thymic epithelial cells contributes to the development of Tregs and thus to the...
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Immunomodulation of dendritic cells by adenylate cyclase toxin from B. pertussis
Jáňová, Hana ; Adkins, Irena (advisor) ; Brdička, Tomáš (referee)
Adenylate cyclase toxin (CyaA) produced by the causative agent of whooping cough Bordetella pertussis, is a key virulence factor important for colonization of the host. CyaA targets preferentially myeloid phagocytes expressing CD11b/CD18 integrin. By elevating cytosolic cAMP in the host cells, CyaA interferes with their phagocytic, chemotactic and oxidative burst capacities. Furthermore, CyaA modulates the secretion of cytokines and the maturation state in LPS-stimulated dendritic cells (DC) by affecting the expression of costimulatory molecules. In this study, we investigated the effects of CyaA on the capacity of murine bone-marrow DC to prime CD4+ and CD8+ T cells in response to ovalbumin epitopes delivered by the CyaA-AC- toxoid, as a model antigen. Further, we examined the possible impact of CyaA on the antigen uptake and processing for MHC class I and II-restricted presentation by DC, as we previously observed a decreased T cell stimulatory capacity of CyaA-treated DC in response to soluble ovalbumin. We found out that the high levels of cAMP generated by CyaA in LPS-stimulated DC account for the decreased presentation of ovalbumin epitopes carried by CyaA-AC- toxoid on MHC class I and II molecules, thereby impairing the CD8+ and CD4+ T cell responses. Whereas CyaA did not influence the...
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New chimeric antigen receptor (CAR) for therapy of human cytomegalovirus (HCMV) infection
Kroutilová, Marie ; Němečková, Šárka (advisor) ; Forstová, Jitka (referee)
Human cytomegalovirus (HCMV, Herpesviridae) can cause severe complications in the infected individuals undergoing hematopoietic stem cell transplantation. Nowadays, these patients are treated using antivirotics or HCMV-specific T cells derived from the seropositive graft donor. This study explored the possibility of redirecting HCMV-non-specific T cells from a seronegative donor towards HCMV-infected cells via chimeric antigen receptor (CAR), i.e. artificially designed T cell receptor. Viral glycoprotein B (gB) has been selected as a target for this receptor. Published sequence of a single chain variable fragment of a human antibody was used for the design of the CAR against gB (gBCAR). After the verification of production and surface localization in cell lines, gBCAR was being introduced into human T cells via lentiviral vectors. Human fetal lung fibroblasts (LEP) infected with HCMV were used as target cells after the expression of gB at their surface was demonstrated. gBCAR functionality was evaluated by the incubation of modified T cells with infected cells and subsequent analysis of media for IFNγ concentration, which was significantly higher in the setting of gBCAR T cells incubated with HCMV-LEP than in the control incubations. The results obtained show the specificity of gBCAR against...
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