Dissertations / Theses on the topic 'T-helper'
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Hewitt, Susannah Louise. "T helper 1/T helper 2 commitment and nuclear localisation." Thesis, Imperial College London, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.415427.
Full textTrüb, Marta. "Follicular T helper cell populations." Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/20466.
Full textSullivan, Andrew. "The role of T-helper 17 and T-helper 22 lymphocytes in beta-lactam hypersensitivity." Thesis, University of Liverpool, 2016. http://livrepository.liverpool.ac.uk/3004574/.
Full textFernández, Barriga Ximena Beatriz. "Efecto inmunomodulador de las células madre mesenquimales sobre linfocitos T helper 1 y T helper 17." Tesis, Universidad de Chile, 2012. http://repositorio.uchile.cl/handle/2250/132032.
Full textLas Células Madre Mesenquimales (MSCs) se han convertido en un interesante campo de estudio. Inicialmente fueron estudiadas por su capacidad de diferenciarse a células de diversos tejidos mesodermales, sin embargo, con el paso de los años se determinó que las MSCs tenían una amplia capacidad de escapar del reconocimiento de células del sistema inmune. Más tarde se descubrió que las MSCs no solo tienen la capacidad de escapar del reconocimiento, sino que también son capaces de inhibir la activación y proliferación de células del sistema inmune. Diversas enfermedades autoinmunes y proinflamatorias están mediadas por linfocitos T, principales células efectores del sistema inmune adaptativo, por tanto, dadas las características inmunosupresoras de las MSCs, han sido propuestas como nueva estrategia terapéutica para el tratamiento de estas enfermedades. Con este objetivo, varios autores han enfocado sus estudios para determinar el mecanismo por el cual las MSCs ejercen este efecto inhibitorio. Algunos autores postulan que el contacto celular, entre MSCs y linfocitos, es indispensable para producir este efecto, sin embargo otros postulan que las MSCs secretan una amplia variedad de factores solubles inmunosupresores que son suficientes para producir el efecto inmunosupresor. Dentro de las estirpes linfocitarias sobre las cuales las MSCs podrían ejercer su efecto inmunosupresor encontramos a los linfocitos T helper (TH), las cuales son células efectoras que se clasifican principalmente en: linfocitos TH1 que participan en la respuesta contra bacterias intracelulares, linfocitos TH2 que participan en la respuesta contra parásitos, linfocitos TH17 que participan en la respuesta contra bacterias extracelulares y hongos y, finalmente, los linfocitos T reguladores (Treg) cuya función es mantener la homeostasis del sistema inmune y promover la tolerancia inmunológica frente a antígenos propios. Durante más de una década fue ampliamente descrita la capacidad inmunosupresora de las MSCs sobre linfocitos T, sin embargo en los últimos años se ha descrito que bajo ciertas condiciones las MSCs producen un efecto estimulador sobre algunas de estas estirpes linfocitarias. El objetivo de este estudio fue determinar si las MSCs suprimen la proliferación y diferenciación de linfocitos TH1 y TH17. Estos linfocitos fueron estudiados ya que se ha descrito que diversas enfermedades autoinmunes se caracterizan por un aumento o desbalance de estas estirpes. Para esto, investigamos si es que el efecto inmunomodulador de las MSCs era dependiente del estado de activación y diferenciación de linfocitos, del ratio MSCs:CD4+, del contacto celular o de factores solubles. Dado que ha sido ampliamente descrito que las MSCs son capaces de secretar basalmente IL-6, la cual corresponde a una citoquina que cumple diversas funciones sobre el sistema inmune, entre ellas promover la secreción de citoquinas y factores de crecimiento necesarias para la respuestas de linfocitos T y que además son capaces de promover la estirpe, altamente proinflamatoria, TH17, y que esta secreción aumenta cuando las MSCs se encuentran frente a estímulos proinflamatorios como IFN-γ o TNF-α, postulamos que la IL-6 secretada por las MSCs es el principal factor soluble involucrado en la inmunomodulación ejercida por las MSCs. Las MSCs fueron obtenidas a partir de médula ósea de ratones C57BL/6 y caracterizadas por el patrón de expresión de antígenos de superficie y por su capacidad de multidiferenciación. Los linfocitos T CD4+ fueron obtenidos a partir de bazo de ratones C57BL/6, purificados mediante kit comercial y cultivados en presencia de citoquinas que favorecen la diferenciación hacia la estirpe TH1 o TH17. Las MSCs fueron agregadas a los cultivos de linfocitos TH1 o TH17 a distintos tiempos de cultivo celular en presencia o ausencia de contacto celular, contacto MSCs-linfocito. La diferenciación de los linfocitos fue medida por medio de la detección de citoquinas intracelulares características de ambas estirpes, IFN-γ e IL-17 para linfocitos TH1 y TH17 respectivamente, por medio de citometría de flujo. Demostramos que las MSCs son capaces de inhibir a linfocitos TH1 independiente del estado de activación y del ratio MSCs:CD4+. Determinamos que el efecto inmunosupresor está presente incluso en condiciones donde no existe contacto celular y que este efecto es independiente de la IL-6 secretadas por las MSCs. A diferencia de lo que ocurre con linfocitos TH1, las MSCs sólo son capaces de inhibir a linfocitos TH17 cuando estas son agregadas a tiempo temprano al cultivo celular y este efecto es dependiente del contacto celular, mientras que cuando las MSCs son agregadas al cultivo a tiempos tardíos, al día 4 de cultivo celular, promueven la diferenciación de linfocitos TH17. Concluimos que el efecto inmunomodulador que ejercen las MSCs sobre linfocitos TH1 y TH17 es por medio de mecanismos diferenciales. El efecto inmunosupresor sobre linfocitos TH1 es independiente de IL-6, sin embargo, no ha sido posible determinar el efecto real que ejerce la IL-6 secretada por las MSCs sobre linfocitos TH17 ya que la diferenciación de linfocitos TH17 requiere de IL-6 en el medio de cultivo. Sin embargo, determinamos que las MSCs en baja concentración no solo pierden su capacidad inhibitoria cuando se encuentran con linfocitos TH17 diferenciados sino que son capaces de promover su diferenciación. Observamos también que la IL-6 proveniente de MSCs podría, bajo ciertas, de revertir este efecto
Mesenchymal Stem Cells (MSCs) have become an interesting field of study. Initially MSCs where studied for their capacity to differentiate into various cell types from different tissues from the mesoderm, however, over the years was determined that MSCs have a large capacity to escape from the recognition by cells from the immune system. Later it was discovered that MSCs not only have the capacity to escape recognition, but are also able to inhibit the activation and proliferation of immune cells. Several autoimmune and proinflammatory diseases are mediated by T cells, major effectors cells of the adaptive immune system, therefore, given the immunosuppressive properties of MSCs they have been proposed as a new therapeutic strategy for treating these diseases. To this end, several authors have focused their studies to determine the mechanisms by which MSCs exert this inhibitory effect. Some authors postulate that cell contact between MSCs and lymphocytes is essential to produce this effect, while others postulate that MSCs secrete a wide variety of immunosuppressive soluble factors that are sufficient to produce the immunosuppressive effect on T lymphocytes. MSCs can exert their immunosuppressive effect on lymphocytes called T helper (TH), which are an effectors cell line mainly classified into: TH1 cells that participate in the response against intracellular bacteria, TH2 cells that participate in the response against parasites, TH17 cells that participate in the response against extracellular bacteria and fungi. Finally there are T regulatory (Treg) cells which main function is to maintain immune system homeostasis and to promote immunologic tolerance against self antigens. For over a decade, it was widely described the immunosuppressive capacity of MSCs on T lymphocytes, however in recent years it has been described that under certain conditions MSCs may produce a stimulatory effect on some of these lymphocytes strains. The aim of this study was to determine whether MSCs are able to suppress TH1 and TH17 proliferation and differentiation. These cells were studied because it has been previously described that many autoimmune disease are characterized by and increase or imbalance of this two strains. For this purpose, we investigated whether de immunomodulatory effect of MSCs was dependent on lymphocytes activation and differentiation state, MSCs: CD4+ ratio, cell contact or soluble factors. It has also been highly described that MSCs are able to secrete basal amounts of IL-6, cytokine which has a variety of function on the immune system, among them, to promote cytokine and growth factor secretion necessary for T cell response, and to promote differentiation of the highly proinflammatory TH17 cells. These IL-6 basal secretion is augmented when MSCs are in presence of proinflammatory stimulus like IFN-γ or TNF-α, thus we postulate that MSCs secreted IL-6 main soluble factor involved in MSCs immunomodulation. MSCs were obtained from mice bone marrow and characterized by their surface antigen expression pattern and their capability of multilineage differentiation. CD4+ T cells were obtained from mice splenocytes, purified by a commercial Kit and cultivated with cytokines that promote the differentiation to TH1 or TH17 cells. MSCs were added to TH1 or TH17 cultures at early or late time points and in the presence or absence of cell to cell contact, MSCs-T cell contact, mediated by a transwell system. The differentiation of TH1 or TH17 cell was measured by the detection of intracellular cytokines characteristics for each population, IFN-γ and IL-17 for TH1 and TH17 cells respectably, by flow cytometry. We demonstrated that MSCs are capable to suppress TH1 cells differentiation despite on their state of activation or MSCs:CD4+ ratio. We determined that the immune suppressor effect of MSCs is present even in the absence of cell to cell contact and that this effect is independent of MSCs secreted IL-6. In contrast with TH1 cells, MSCs are only capable to suppress TH17 cells when added at early time points of cell culture and that this effect requires cell to cell contact, while promoting TH17 differentiation when added at later time points, at day 4 of cell culture. We concluded that the immune modulator effect of MSCs on TH1 and TH17 cells is mediated by differential mechanism. The immune suppressor effect on TH1 cells is independent from IL-6, though it was not possible to determined de real effect of MSCs secreted IL-6 over TH17 cells, since the TH17 differentiation media requires IL-6. However, we determined that low concentration of MSCs in the coculture, fail to inhibit TH17 differentiation more over they promote an augmentation of TH17 cells. We also observed that under certain culture conditions MSCs secreted IL-6 may revert this effect
Bergmann, Claudia C. "T helper regulation a theoretical approach /." [S.l.] : [s.n.], 2000. http://deposit.ddb.de/cgi-bin/dokserv?idn=96215511X.
Full textJansson, Andreas Biotechnology & Biomolecular Sciences Faculty of Science UNSW. "Modelling T helper cell activation and development." Awarded by:University of New South Wales. School of Biotechnology and Biomolecular Sciences, 2006. http://handle.unsw.edu.au/1959.4/30602.
Full textAlfonso, Christopher. "The function of helper T cell epitopes." Thesis, University of Newcastle Upon Tyne, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.319190.
Full textPassini, Nadia. "Molecular mechanisms of T helper 1 and T helper 2 cell development : differential signaling in response to Interleukin-12." Thesis, Open University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.299005.
Full textKelly, Helena T. "The role of T helper 1 and T helper 2 lymphocyte subsets in the pathogenesis of experimental autoimmune uveoretinitis." Thesis, University of Aberdeen, 1995. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU543992.
Full textWang, Qixin. "Genetic analysis of differentiation of T-helper lymphocytes." Thesis, University of Southern California, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=1546784.
Full textIn the human immune system, T-helper cells are able to differentiate into two lymphocyte subsets: Th1 and Th2. The intracellular signaling pathways of differentiation form a dynamic regulation network by secreting distinctive types of cytokines, while differentiation is regulated by two major gene loci: T-bet and GATA-3. We developed a system dynamics model to simulate the differentiation and re-differentiation process of T-helper cells, based on gene expression levels of T-bet and GATA-3 during differentiation of these cells. We arrived at three ultimate states of the model and came to the conclusion that cell differentiation potential exists as long as the system dynamics is at an unstable equilibrium point; the T-helper cells will no longer have the potential of differentiation when the model reaches a stable equilibrium point. In addition, the time lag caused by expression of transcription factors can lead to oscillations in the secretion of cytokines during differentiation.
Van, Essen Dominic James. "Studies on helper T cell priming and memory." Thesis, Imperial College London, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.300423.
Full textPurvis, Harriet Amanda. "Regulation of human T helper 17 cell responses." Thesis, University of Newcastle Upon Tyne, 2013. http://hdl.handle.net/10443/1822.
Full textColizzi, V. "Antigen specific T helper factor in contact sensitivity." Thesis, Open University, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.381008.
Full textGuvenel, Aleks Kamer. "Human helper T cell responses to RSV infection." Thesis, Imperial College London, 2016. http://hdl.handle.net/10044/1/57117.
Full textDe, Mattia Fabrizio. "Rétro-contrôle de l'activation des lymphocytes T helper "mémoire"." Doctoral thesis, Universite Libre de Bruxelles, 2001. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/211685.
Full textLu, Tangying (Lily). "Cannabinoids suppress dendritic cell-induced T helper cell polarization." [Tampa, Fla] : University of South Florida, 2006. http://purl.fcla.edu/usf/dc/et/SFE0001790.
Full textNeeraj. "Studies on equine helper T cells and Fcγ receptors." Thesis, University of Cambridge, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.627077.
Full textAlizadeh, Darya. "Doxorubicin and T Helper Lymphocytes: Unexpected Allies Against Cancer." Diss., The University of Arizona, 2013. http://hdl.handle.net/10150/307049.
Full textSarris, Milka. "Dynamics of helper T cell and regulatory T cell interactions with dendritic cells." Thesis, University of Cambridge, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.611896.
Full textBhattacharyya, Nayan. "The Regulation of CD4+ T Lymphocyte Responses to Mycobacterial Infection." Thesis, The University of Sydney, 2019. https://hdl.handle.net/2123/21860.
Full textTibbitt, Christopher Andrew. "The role of T cell receptor signal intensity in T helper 17 cell development." Thesis, University of Newcastle upon Tyne, 2015. http://hdl.handle.net/10443/2885.
Full textCodlin, Sandra Maria Susan. "A novel palindromic element common to the granulocyte macrophage colony stimulating factor gene and the Th2 expressed cytokine genes : interleukin (IL) 4, IL 5 and IL 13 acts as a potent enhancer of transcription." Thesis, King's College London (University of London), 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.249674.
Full textCrome, Sarah Anne. "Development, regulation and function of human T helper 17 cells." Thesis, University of British Columbia, 2011. http://hdl.handle.net/2429/33078.
Full textArthur, R. P. "In vitro functional studies of rat T helper cell heterogeneity." Thesis, University of Oxford, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.355759.
Full textScriba, Thomas Jens. "HIV T helper immunity studied with HLA class II tetramers." Thesis, University of Oxford, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.425908.
Full textGraham, Christine Marian. "Anti-viral immunity : helper T cells in influenza virus infection." Thesis, Oxford Brookes University, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.444320.
Full textCole, Jennifer Louise. "Pathways of helper CD4 T cell allorecognition in humoral alloimmunity." Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.607868.
Full textThomas, Jessica. "T follicular helper cells in health and inflammatory bowel disease." Thesis, King's College London (University of London), 2013. https://kclpure.kcl.ac.uk/portal/en/theses/t-follicular-helper-cells-in-health-and-inflammatory-bowel-disease(1c45e306-6a7b-4d84-b02f-e4e1c500dbea).html.
Full textFeltquate, David Marc. "Helper T Cell Differentiation in DNA-Immunized Mice: A Dissertation." eScholarship@UMMS, 1998. http://escholarship.umassmed.edu/gsbs_diss/181.
Full textBinet, Bénédicte. "Régulation épigénétique de la programmation des lymphocytes T CD4 par SETDB1." Thesis, Toulouse 3, 2017. http://www.theses.fr/2017TOU30217.
Full textCD4 T lymphocytes play a central role in the defense of mammal organisms against infections by pathogens and the development of tumors. Upon activation, naïve CD4 T cells differentiate into distinct helper cell subsets depending on environmental cues. T helper cells are key players of the immune system as they finely orchestrate immune responses in a danger-adapted manner. The process of T helper differentiation relies on the establishment of complex and lineage-specific gene expression programs. The dynamics and stability of these programs are regulated at the chromatin level through epigenetic control of cis-regulatory elements. My thesis objective was to investigate the epigenetic pathways involved in the regulation of enhancer activity in CD4 T cells. In this purpose, we studied the role of the H3K9 specific methyltransferase SETDB1 in the differentiation of Th1 and Th2 cells, which are strongly antagonistic. We report that SETDB1 critically represses the Th1 gene expression program. Indeed, Setdb1-deficient naïve T cells show exacerbated Th1 priming. Moreover, when exposed to a Th1-instructive signal, SETDB1-deficient Th2 cells cross lineage boundaries and transdifferentiate into Th1 cells. Surprisingly, SETDB1 does not directly target Th1 enhancers to heterochromatin. Instead, SETDB1 deposits the repressive H3K9me3 mark at a restricted and cell type specific set of endogenous retroviruses, strongly associated with genes involved in immune processes. Further bioinformatic analyses indicated that these retrotransposons flank and repress Th1 gene cis-regulatory elements or behave themselves as Th1 gene enhancers. Thus, H3K9me3 deposition by SETDB1 ensures T cell lineage integrity by repressing a repertoire of ERVs that have been exapted into cis-regulatory modules to shape and control the Th1 gene network
Özgönen, Özlem Şahin Ünal. "Malign ve tüberküloz plörezi ayırıcı tanısında T helper 1 ve T helper 2 sitokinlerden IFN-y,IL-12,IL-18 ve IL-10'un tanısal değeri /." Isparta: SDÜ Tıp Fakültesi, 2006. http://tez.sdu.edu.tr/Tezler/TT00277.pdf.
Full textGaudenzio, Nicolas. "Étude de l'interaction entre les mastocytes et les lymphocytes T helper." Toulouse 3, 2012. http://thesesups.ups-tlse.fr/1834/.
Full textMast cells have been classically associated to allergic disorders, however several studies describe their involvement in the inflammatory response. Mast cells are often observed in tissues in close apposition with CD4 T cells (TH). The aim of my thesis is to better characterize the nature of mast cell/TH interaction and in particular the mast cell capacity to act as antigen presenting cell and the consequences for the TH cell response. We first addressed this question using mouse primary mast cell lines derived from peritoneal progenitors (PCMC) used as antigen presenting cell to activate cognate OTii T cells with OVA peptide. Our results show that in vitro treatment of PCMC with IFN-gamma and IL-4 induced surface expression of mature MHC class II and costimulatory molecules. When IFN-gamma primed PCMC were used as antigen presenting cells for Helper T (TH) cells, they induced activation of effector T cells but not of their naive counterparts. Confocal laser scanning microscopy showed that TH cells formed immunological synapses and polarized their secretory machinery towards antigen-loaded PCMC. Finally, upon cognate interaction with TH cells, mast cells lowered their threshold of activation via FcepsilonRI. These results show that mast cells can specifically cooperate with class II restricted TH cells. In a second part, we investigated the functional impact of mast cell antigen presentation on human T cell-mediated responses. In vitro, human mast cells form productive immunological synapses with antigen-experienced TH cells. These interactions promote the generation of interleukin 22 (IL-22) producing TH cells (either pure TH22 or IL-22 plus IFN-gamma-producing TH cells) from the circulating CD4+ memory T cell pool via a tumor necrosis factor (TNF-alpha) - and IL-6-dependent mechanism. Three-color immunohistochemistry and confocal laser scanning microscopy reveal a rich infiltrate of IL-22+ TH cells in psoriatic skin biopsies. Most of the IL-22+ TH cells are found in contact with mast cells and co-express IFN-gamma, suggesting that IFN-gamma+IL-22+ TH cells are generated in vivo upon interaction with mast cells. Our results reveal a novel functional trait of mast cells by showing that they can shape the inflammatory potential of human TH lymphocytes in tissues, by providing activating signals and skewing the TH cell response toward the production of IL-22
Burkhart, Christoph. "Characterization of the T helper cell response to vesicular stomatitis virus /." Zürich, 1994. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=10799.
Full textAdhikary, Dinesh. "Investigation of the T helper cell response against Epstein-Barr virus." Diss., [S.l.] : [s.n.], 2006. http://edoc.ub.uni-muenchen.de/archive/00005277.
Full textGalle, Cécile. "Inflammatory and helper T lymphocyte responses in human abdominal aortic aneurysm." Doctoral thesis, Universite Libre de Bruxelles, 2006. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210815.
Full textAbdominal aortic aneurysm (AAA) is a chronic degenerative disease that usually affects men over 65 years with an estimated prevalence of 5%. Aneurysm rupture represents a catastrophic event which carries a mortality rate of almost 90%. Current therapeutic options for AAAs measuring 5.5 cm in diameter or larger are based on prophylactic surgery, including conventional open reconstruction and endovascular stent-graft insertion. For patients with small asymptomatic AAAs (4.0 up to 5.5 cm in diameter), evidence from two recent large randomized controlled trials indicates no long-term survival benefit from immediate elective surgical repair as compared to imaging surveillance until aneurysm expands to 5.5 cm. This highlights the need for development of novel medical management strategies, including selective pharmacologic approaches, directed at preventing aneurysm expansion. In this regard, it is expected that a detailed knowledge of the pathobiology of human AAA lesion and a better understanding of pathophysiological mechanisms underlying initiation and progression of aneurysmal degeneration, particularly the specific involvement of T lymphocytes, will have special relevance to this challenging issue.
Inflammatory and helper T-cell responses in abdominal aortic aneurysm :controversial issues
Innate and inflammatory responses to endovascular versus open AAA repair. The occurrence of early acute systemic inflammatory responses after conventional open AAA repair is widely recognized and is thought to lead to the development of organ dysfunction and multiple organ failure, responsible for a large proportion of morbidity and mortality associated with aortic surgery. New therapeutic strategies designed to avoid ischemia-reperfusion injury related to aortic cross-clamping and to minimize the degree of tissue damage have thus been developed recently. Specifically, the advent of endovascular techniques has radically extended management options for patients with AAA. Although the method is believed to offer a clear short-term benefit over open repair, notably as regards restricted perioperative haemodynamic parameter fluctuations, reduced blood loss, briefer duration of surgery, shorter hospital stay, and lower 30-day mortality and complication rates, conflicting data are available regarding the exact nature and extent of the inflammatory events arising after such endoluminal procedures ;while several authors have indeed reported that endovascular AAA repair can determine a less intense and extensive inflammatory response, others have unexpectedly observed that the method may elicit a strong inflammatory response, the so-called « postimplantation syndrome ».
Adaptive cellular immune responses in human aneurysmal aortic lesion.
The inflammatory nature of AAA disease has long been suggested by the presence of a great number of CD4+ T lymphocytes in the outer media and adventitia of human AAA lesion. Interestingly, such infiltrating T-cell populations may have significant implications in the process of aneurysm dilation, since cytokines produced by T cells, notably IFN-gamma, have previously been shown to modulate production of matrix-degrading enzymes by resident macrophages and to induce apoptosis of medial SMCs. Through these key pathological mechanisms, T cells could potentially contribute to orchestrate aortic wall connective tissue disordered remodeling and degradation, and promote extensive disruption of elastic media, ultimately leading to aneurysmal degeneration. Nevertheless, despite their relative abundance in human AAA wall tissues, there is limited and controversial information as regards the functional profile of lesional lymphocytes, the exact nature of aortic wall adaptive cellular responses, and the etiologic role of T cells and their cytokines in initiation and progression of the aneurysmal process. Indeed, both Th1-type and Th2-type responses have been identified in human studies and experimental animal models of AAA.
Aims of the work
The main objectives of our work were to explore the innate and adaptive cellular immune responses in human AAA. In the first part of our work, we aimed to examine prospectively innate and inflammatory responses arising in a non-randomised cohort of patients undergoing endovascular versus open AAA repair. In the second part of our work, we focused our efforts on characterizing the nature of adaptive cellular immune responses and the phenotypic and functional repertoire of T cells in human AAA wall tissues obtained from a consecutive series of patients undergoing open AAA repair. Specifically, we sought to determine whether type 1 or type 2 responses occur predominantly in advanced AAA lesion.
Main experimental findings
Limited inflammatory response after endovascular AAA repair. Serial peripheral venous blood samples were collected preoperatively, immediately after declamping or insertion of endograft, and after 1, 3, 6, 12, 24, 48, and 72 hours. We first examined the acute phase reaction and liberation of complement cascade products using turbidimetric method and nephelometry. We found that endovascular repair produced lower postoperative CRP, leucocytosis, neutrophilia, and C3d/C3 ratio as compared to open surgery. We next analyzed surface expression of activation markers on peripheral CD3+ T cells using flow cytometry. We observed a strong upregulation of CD38 after open but not endovascular repair. Analysis of CD69 and CD25 molecules revealed no perioperative fluctuations in any group. We then investigated release of various circulating soluble cell adhesion molecules, proinflammatory cytokines, and chemokines using enzyme-linked immunosorbent assays. We demonstrated that both procedures are characterized by similar increases in ICAM-1 and IL-6 levels. Finally, tendency towards high levels of TNF-alpha and IL-8 was detected in endovascular repair, but data failed to reach statistical significance.
Predominance of type 1 CD4+ T cells in human aneurysmal aortic lesion. We have developed a tissue enzymatic digestion and cell extraction procedure to isolate intact mononuclear cells from aortic wall segments. This original cell isolation protocol enabled us to examine ex vivo the presence, phenotype, and cytokine secretion profile of infiltrating T lymphocytes freshly isolated from human AAA tissues for comparison with their circulating counterparts using flow cytometry. We found that both populations of infiltrating CD4+ and CD8+ T cells display a unique activated memory phenotype, as assessed by an increased expression of CD69 and HLA-DR activation antigens, downregulation of CD62L molecule, and predominant expression of the CD45RO isoform characteristics of memory cells. In addition, we identified the presence in human aneurysmal aortic wall lesion of CD4+ T cells producing high levels of IFN-gamma but not IL-4, reflecting their type 1 nature. In an additional series of experiments, cytokine gene expression was determined in whole aneurysmal and non-diseased aortic samples using LightCycler-based quantitative real-time reverse transcription-polymerase chain reaction. The molecular basis of type 1 or type 2 dominant responses was further specified by analyzing mRNA levels of transcription factors specifically involved in Th1 or Th2 differentiation such as T-bet and GATA-3. We demonstrated that aneurysmal aortic specimens exhibit high transcript levels of IFN-gamma but not IL-4, and consistently overexpressed the IFN-g-promoting cytokine IL-12 and the type 1-restricted transcription factor T-bet, further establishing the prominent type 1 nature of aortic wall responses. Moreover, such selective tissue expression of IL-12 and T-bet in the vessel microenvironment points to a potential role for these signals in directing aortic wall responses towards a type 1 phenotype.
Conclusions
Our findings indicate that endovascular AAA repair is associated with a lesser degree of acute phase reaction, peripheral T-cell activation, and release of complement proteins as compared to conventional open surgery, suggesting that the innate and inflammatory responses to AAA repair are significantly attenuated by the endovascular approach as compared to the traditional open reconstruction. These results support the view that the endoluminal procedure represents an attractive alternative to open surgery for the treatment of large aneurysms. On the other hand, we have demonstrated that Th1 cell infiltrates predominate in human end-stage AAA lesion. These observations are relevant for helping clarify the pathobiology of human AAA tissues and defining prospects for the prevention of aneurysm expansion. Indeed, identification of such infiltrating populations of IFN-gamma-producing CD4+ T cells not only provide new insights into the pathogenesis of the disorder, but could also serve as a basis for the development of novel medical management strategies directed at preventing aneurysm formation and progression, including therapeutic approaches based on the modulation of aortic wall responses and designed to selectively target T-cell activation and cytokine production. In this respect, the present work provides experimental evidence in support of the emerging concept that, although multifactorial, aneurysm disease may be regarded as a Th1-driven immunopathological condition, and suggests that strategies targeting IFN-gamma could be a particularly exciting and fruitful avenue for further investigation. Ongoing clinical and basic research in these areas can be expected to yield design of promising pharmacologic approaches to control AAA expansion. From a clinical perspective, such efforts have the potential to dramatically influence both the outcome and management of this common and life threatening condition.
Doctorat en sciences médicales
info:eu-repo/semantics/nonPublished
Rasheed, Mohammed Ata Ur. "Gene signatures and functional analysis of follicular B helper T cells." [S.l.] : [s.n.], 2006. http://www.diss.fu-berlin.de/2006/538/index.html.
Full textGetahun, Andrew. "Antibody Feedback Regulation : From Epitope Masking to T Helper Cell Activation." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-4580.
Full textBurtles, S. S. "An in vitro analysis of T helper cell tolerance in mice." Thesis, University of Bristol, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233577.
Full textAtalar, Kerem Benjamin. "The role of microRNAs in T helper cell function and differentiation." Thesis, King's College London (University of London), 2012. https://kclpure.kcl.ac.uk/portal/en/theses/the-role-of-micrornas-in-t-helper-cell-function-and-differentiation(2686b0af-6ac9-4219-bbf8-35a4d9baffe8).html.
Full textFang, Miaoqing. "Stochastic gene expression during lineage specification of single T helper lymphocytes." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/78138.
Full textCataloged from PDF version of thesis.
Includes bibliographical references (p. 118-125).
The adaptive immune system is an extraordinarily diverse inventory comprised of highly specialized cells, the differentiation of which requires numerous lineage specifications at various developmental stages. The precise control of immune cell differentiation and the delicate balance of their population composition are crucial for effective protection against infectious environmental agents, without triggering autoimmune responses or allergies. It is therefore important to understand at the molecular level in individual cells how lineage commitment is regulated. I explored the heterogeneous gene expression during the lineage specification of single T helper cells, by quantitatively measuring mRNA and protein levels. I have discovered a paradigm of cell lineage specification governed by the signaling interplay between extracellular cues and intracellular transcriptional factors, where the strength of extracellular signaling dominates over the intracellular signaling components. In the presence of extracellular cues, T helper cells stochastically acquire any intermediate Thl/Th2 states. The states of T helper cells can be gradually tuned by depriving availability of extracellular cytokines, which are produced stochastically by a small subpopulation of cells. When extracellular cues are removed, the weak intracellular signaling network reveals its effect, leading to classic mutual exclusion of antagonistic transcriptional factors.
by Miaoqing Fang.
Ph.D.
Cui, Xiaotong. "Interactions between Regnase-1 and Roquin Regulate Helper T Cell Polarization." Kyoto University, 2018. http://hdl.handle.net/2433/232429.
Full textPowell, Michael D. "Insights Into the Regulatory Requirements for T Follicular Helper Cell Development." Diss., Virginia Tech, 2019. http://hdl.handle.net/10919/89085.
Full textPh. D.
Specialized cells called T helper cells serve as a critical interface between the innate (first line of defense) and adaptive (specialized and long-term) immune systems. During the course of an infection, T helper cells are responsible for orchestrating the immune-mediated elimination of invading viruses, bacteria, and parasites. This wide breadth of functionality is achieved through the formation of distinct T helper subsets including T helper 1 (TH1), TH2, TH17, and T follicular helper (TFH) populations. Individual subsets have distinct developmental requirements and have unique functions within the immune system. For example, TFH cells are required for the production of effective antibodies that recognize invading pathogens, leading to their subsequent elimination. This naturally occurring process is the basis for a number of modern medical therapies including vaccination. Conversely, aberrant generation of antibodies that recognize host tissues can result in the onset of various autoimmune diseases including lupus, multiple sclerosis, and crohn’s disease. Due to the importance of TFH cells to human health, there is intense interest in understanding how these cells are formed. It is recognized that the generation of these therapeutically important immune cells is mediated by numerous cell-extrinsic andintrinsic influences, including proteins in their cellular environment called cytokines, and important proteins inside of the cell called transcription factors. However, as this is a complicated and multi-step process, many questions remain regarding the identity of these cytokines and transcription factors. The work in this dissertation seeks to understand how cellextrinsic cytokine signals and cell-intrinsic transcription factor activities are integrated to properly regulate TFH cell development. Collectively, this body of work significantly advances our understanding of the regulatory mechanisms that govern TFH cell differentiation, setting the basis for the rational design of novel immunotherapeutic strategies and increasingly effective vaccines.
Stott, Lisa M. "Characterisation of the alloreactive T helper epitopes on the RhD protein." Thesis, University of Aberdeen, 2002. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU170746.
Full textHall, Andrew M. "Characterisation of T-helper cell subsets in human autoimmune haemolytic anaemia." Thesis, University of Aberdeen, 2001. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU141805.
Full textSabir, Suleman Rahman. "Dissecting the role of T-follicular helper cells in experimental atherosclerosis." Thesis, University of Glasgow, 2015. http://theses.gla.ac.uk/7665/.
Full textHuseby, Eric Sigurd. "Helper and cytotoxic T cell responses specific for myelin basic protein /." Thesis, Connect to this title online; UW restricted, 2000. http://hdl.handle.net/1773/8361.
Full textGeiger, Rebekka. "Analysis of the human naïve T cell repertoire and identification of a novel T helper subset." [S.l.] : [s.n.], 2009. http://www.zb.unibe.ch/download/eldiss/09geiger_r.pdf.
Full textKawamoto, Shimpei. "Preferential Generation of Follicular B Helper T Cells from Foxp3+ T Cells in Gut Peyer's Patches." Kyoto University, 2011. http://hdl.handle.net/2433/142110.
Full textKwong, Pearl Chu. "Characterization of an antigen-specific T helper cell clone and its products." Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/27366.
Full textScience, Faculty of
Microbiology and Immunology, Department of
Graduate
Bending, David Alexander. "The behaviour of T helper 17 (Th17) cells in health and disease." Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609853.
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