<p>S. 1-80: sammanfattning, s. 81-159: 7 uppsatser</p> / digitalisering@umu

Le diabète de type 1 (DT1) est une maladie auto-immune qui résulte en la destruction des cellules (ß des îlots de Langerhans par les cellules du système immunitaire. Des travaux précédents de notre laboratoire ont identifié la cytokine "Thymic Stromal Lymphopoietin" (TSLP) comme étant un stimulus tolérogénique pour les cellules dendritiques (DCs) chez le modèle murin du DT1, la souris "Non Obese Diabeiic" (NOD). Les DCs conditionnées à la TSLP (TSLP-DCs) présentent un phénotype semi-mature, sont capables d’induire une réponse Th2 ainsi qu’une conversion et une expansion des lymphocytes T régulateurs (Tregs) in vitro et protègent les souris NOD contre le DT1. Ces observations nous ont amené à investiguer les mécanismes qui entraînent cette protection contre le DT1. Les travaux décrits dans ce mémoire montrent que les TSLP-DCs injectées chez les souris NOD migrent vers la rate, de manière privilégiée. Ces observations nous ont amené à étudier l’influence des TSLP-DCs sur la réponse Th1/Th2 au niveau de la rate. Nous avons observé que les splénocytes CD4[indice supérieur +] et CD8[indice supérieur +] de souris injectées avec des TSLP-DCs exprimaient moins d’IFN? par rapport au souris témoins (splénocytes des souris injectées avec des LPS-DCs). Ces résultats suggèrent une diminution de la réponse Th1 chez ces splénocytes. Par contre, les résultats obtenus avec l’IL-10 ne nous ont pas permis de conclure quant à l’influence des TSLP-DCs sur la réponse Th2. Cependant, nous avons confirmé la capacité des TSLP-DCs à induire la conversion des lymphocytes T CD4[indice supérieur +]CD25[indice supérieur -] en Tregs CD4[indice supérieur +]CD25[indice supérieur +]Foxp3[indice supérieur +]. Nous avons aussi montré que ces Tregs partiellement convertis inhibent la prolifération de lymphocytes T 8.3-CD8[indice supérieur +] diabétogènes, et empêchent la production d’IFN?. Les Tregs convertis en présence de TSLP-DCs ou de LPS-DCs ont également été injectés à des souris 8.3-NOD.RAG2[indice supérieur -/-]. Les résultats ont révélé que seuls les Tregs différenciés en présence de TSLP-DCs ont la capacité d’empêcher le développement du DT1. Nos travaux suggèrent que la diminution de la réponse Th1 et l’induction d’une population efficiente de lymphocytes Tregs font partie des mécanismes utilisés par les TSLP-DCs pour protéger les souris NOD contre le DT1.

The B cell repertoire in the neonatal immune system (IS) is characterised by reactivity towards self-components, including other immunoglobulin (Ig) V-regions. These properties have been suggested to be a requirement for the development of a normal immune system. DNA sequencing of two interacting Ig idiotypes, derived from neonatal, preimmune mice, demonstrated that such idiotypic connectivity is germ- line encoded and devoid of VDJ junctional diversity. The serum levels of the same Ig idiotypes were studied in normal mice and demonstrated that the expression in serum fluctuated over time in a pattern compatible with a complex dynamic system. In contrast, similar analyses in autoimmune mice or humans demonstrated fluctuations in Ig titers that differed significantly from the healthy individuals. These findings suggested that pathological autoimmunity may be associated with fundamental alterations in the dynamics of natural antibody (ab) expression. This was further investigated in the nonobese diabetic (NOD) mouse, an animal model for human Type I diabetes. Suppression of the early B cell development in the NOD mouse prevented the development of diabetes, suggesting a role for B cells/Igs in the development of diabetes in these mice. Furthermore, neonatal injections of polyclonal Ig preparations or single, monoclonal natural abs inhibited disease induction. The prevention of diabetes development by one such natural ab was demonstrated to be dependent on both the dose injected and the timing of administration. Studies of the B cell repertoire development in NOD mice, compared to normal mice, by DNA-sequence analyses of IgVH rearrangements utilising genes from the most D-proximal Vh family, Vh7183, supported the idea of an aberrant B cell repertoire in this mouse model. Thus, the adult NOD mouse retained a neonatal pattern of Vh7183 rearrangements. This pattern could, however, be "normalised" by neonatal injection of a natural antibody, previously demonstrated to prevent the development of T cell dependent autoimmunity in the NOD mouse. / <p>Diss. (sammanfattning) Umeå : Umeå universitet, 1993, härtill 6 uppsatser</p> / digitalisering@umu

Type 1 diabetes mellitus (T1D) is an autoimmune disorder that targets the insulin-producing β-cells. The gut may play a role in the pathogenesis of T1D, as genetically-susceptible individuals and animal models of T1D exhibit increased intestinal permeability and improving gut barrier function can interfere with the onset of diabetes. Moreover gut-derived peptides are capable of modifying barrier function and regulate β-cell mass via effects on proliferation and apoptosis. I tested whether chronic administration of glucagon-like peptide-2 (GLP-2), a peptide which potently improves gut barrier function, modifies diabetes onset in a mouse model of T1D, the non obese diabetic (NOD) mouse. Although chronic treatment with a long-acting GLP-2 analogue was associated with improved intestinal barrier function, it failed to delay the onset of T1D. Once the autoimmune attack is initiated, pathogenic T-cells infiltrate the islets and trigger the death of β-cells. Studies in animal models have revealed that β-cells exhibit a compensatory response in the initial stages of the immune attack, which eventually fails, resulting in β-cell mass deficiency and onset of T1D. Glucagon-like peptide-1 (GLP-1) exerts both proliferative and anti-apoptotic actions on β-cells. I hypothesized that chronic activation of the GLP-1 receptor (GLP-1R) would delay or prevent the loss of functional β-cell mass in the NOD mouse. I have shown that chronic administration of the GLP-1R agonist exendin-4 significantly delayed the onset of diabetes and enhanced β-cell mass. Furthermore, GLP-1R activation was associated with a reduction of islet-infiltrating immune cells, as well as changes in lymphocyte subpopulations. Consequently, I addressed whether the GLP-1R has a role in the immune system of NOD and C57Bl/6 mice. GLP-1R mRNA transcripts were detectable in several immune subpopulations, and GLP-1R activation was associated with cAMP production in primary splenocytes and thymocytes. Furthermore I demonstrated that GLP-1R signaling controls proliferation of thymocytes and lymphocytes, and is required for maintaining peripheral regulatory T-cells. In summary, these studies establish that while GLP-2R activation is not sufficient to modify disease onset in a murine model of T1D, GLP-1R activation reduces the extent of diabetes development by exerting actions on β-cells and the immune system.

Interest in cellular immunotherapy has increased with the recognition of the pivotal role that dendritic cells (DC) play in the adaptive immune system. The preparation of DC to present tumour antigens and subsequent induction of tumour specific T cells have been widely documented. This thesis studied the ability of cord blood (CB) stem cells to differentiate into functional CD34+DC, followed by the optimisation of electroporation of RNA into these cells. Total RNA derived from a leukaemic cell line and a primary human leukaemic sample was electroporated into CD34+DC DC and we were able to generate anti-leukaemic cytotoxic T lymphocytes (CTL). The CTL specifically targeted leukaemia but not normal cells. While the in vitro data showed promising results of the CTL specificity, a NOD-SCID model of human ALL was established to allow the CTL to be tested in vivo. We established a reproducible model of human ALL in NOD-SCID mouse using four primary human ALL samples. The adoptively transferred anti-leukaemic CTL into the ALL bearing NOD-SCID mice showed that ALL engraftment was significantly delayed. However, the addition of total RNA loaded CD34+DC DC did not enhance the in vivo CTL effect. Lastly, by dissecting the CTL response, we found that the polyclonal CTL were targeting survivin, HM1.24 and CT-7 antigens. The CTL clones generated from these polyclonal CTL showed high specificity for leukaemia but not normal cells. In conclusion, these preliminary data support the use of total RNA electroporated CD34+DC as a means of inducing anti-leukaemic CTL, and have demonstrated the efficacy of the CTL in a NOD-SCID model of ALL. This study has also provided insight into the polyclonal CTL response and future studies will likely continue along this path.

Diss. (sammanfattning) Umeå : Univ., 2005. / Härtill 4 uppsatser.

Diss. (sammanfattning) Umeå : Umeå universitet, 2006. / Härtill 4 uppsatser.

Thesis (Ph.D. in Immunology) -- University of Colorado Denver, 2007. / Typescript. Includes bibliographical references (leaves 182-202). Free to UCD affiliates. Online version available via ProQuest Digital Dissertations;

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

Orientador: Ricardo de Lima Zollner / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-08T15:14:13Z (GMT). No. of bitstreams: 1 Vilella_ConceicaoAparecida_D.pdf: 48895468 bytes, checksum: c4753d07008661a967f99ba5800aaf87 (MD5) Previous issue date: 2005 / Resumo: No modelo experimental referenteà linhagem de camundongos NOD (non obese diabetic) a manifestação do diabetes autoimune é espontâneo semelhante ao observado em humanos, o qual se desenvolve entre a 12a e 24a semana de vida com prevalência variável nas diversas colônias, entre 60-90% em fêmeas e 0-20% nos machos. Os estudos dos mecanismos autoimunes do diabetes sugerem o desequilíbrio entre as populações de linfócitos Th1 e Th2 com predomínio do fenótipo Th1 com mecanismos efetores que levam a apoptose da célula 'beta' produtora de insulina. Inúmeros trabalhos sugerem que a apoptose das células 'beta' esteja associada à manifestação do diabetes tanto em modelos experimentais como em humanos. Componentes apoptóticos como Fas/Fas-L, IL-1f3, IFN-y e. TNF-a tem sido associados aos mecanismos efetores da apoptosedas ilhotas. Gangliosídeos podem bloquear de forma seletiva a produção de citocinas próinflamatórias como IFN-ye TNF-a (Th1) inibindo desta forma, a proliferação de linfócitos T. Por outro lado, citocinas antiinflamatóriascomo IL-4 e TGF-f3 podem ter sua síntese estimulada por estes compostos. No presente trabalho, investigamos o efeito do tratamento de gangliosídeos (GM1, GD1a, GD1b, GT1b) sobre a incidência do diabetes mellitus e da insulite em camundongos NOD. Foram monitorados os níveis glicêmicos, os aspectos morfológicos (índice de infiltrado, imunoistoquímica para detecção de subpopulações de linfócitosTCD4+,CD8+e macrófagos-CD11), a expressão gênica de citocinas, moléculas apoptóticas e antiapoptóticas e níveis séricos de citocinas IL-12,IL-4,TGF-f3,TNF-a,IFN-V. Os resultados sugerem que a administração de gangliosídeos a partir da 4a semana de vida do animal impede a manifestação do diabetes, modula o infiltrado inflamatório preservando células f3,diminui a resposta Th1 em ilhotas e eleva os níveis séricos de citocinas antiinflamatóriascomo IL4 e TGFf3,além de induzir a morte celular em linfócitos. Assim, o desenvolvimento de estudos adicionais dirigidos aos mecanismos de ação de gangliosídeos na manifestação do diabetes autoimune, é relevante,e fundamental para estratégiasde tratamentos mais efetivos / Abstract: The 'beta' cells destruction on diabetes type 1 autoimmune knowledge was derivative from NOD (diabetic non obese) mouse as experimental model, which have demonstrated great potential for drugs or immunotherapy's study. In this model, the diabetes manifestation occurs spontaneously like the observed in human, among 128-248 week of life. The prevalence could be varied from 60-90% in females and 0-20% in males. The autoimmune mechanism study suggests the imbalance between Th1 and Th2 response with predominance Th1 phenotype (IL-1(3,TNF-a, IFN-y). Thus, it was necessary the study of the Th1 and Th2 cytokines related to autoimmunity of the diabetes in NOD mouse. Moreover, it believed that apoptosis of the 'beta' cells it was associated with the diabetes manifestation in both human and experimental models. In such studies FaslFas-L were related with IL-1(3,IFN-y and TNF-a as effectors molecules of the cell death pancreatic islets. Gangliosides can block, in a selective manner, the pro-inflammatory (Th1) cytokines preduction like IFN-y and TNF-a and inhibit the T cells proliferation. However, these compounds can stimulate the synthesis of anti-inflammatory cytokines, like IL-4 and TGF-'beta'. In the present wOrk,we analyze the effect of the gangliosides (GM1,GD1a,GD1b, GT1b) treatment on diabetes mellitus manifestation in NOD mice. The glucose levels, injury index, CD4, CDa and CD11 immunohistochemical labeling, cytokines and apoptotic related molecules gene expression analyses and IL-12, IL-4, TGF-'beta' - TNF-'alfa' and IFN-y detection by immunoassay, were monitored. Our results showed that the ganglioside treatment frem 4th week of life prevents the on set of autoimmune diabetes, the inflammatory infiltrate installation. Th1 response can be suppresses by these compounds by the increase anti-inflammatory cytokines and the T cell apoptosis induction, besides the 'beta' cells preservation. Therefore take together these results reinforce the immunomodulatory action of gangliosides treatment on the diabetes mellitus manifestation / Doutorado / Ciencias Basicas / Doutor em Clínica Médica