Made available in DSpace on 2017-07-21T19:26:10Z (GMT). No. of bitstreams: 1 Pedro Jeferson Miranda.pdf: 3220140 bytes, checksum: a557a7dc630657c2bc53d73eb4fd7f48 (MD5) Previous issue date: 2014-09-03 / Fundação Araucária de Apoio ao Desenvolvimento Científico e Tecnológico do Paraná / The emergence is a phenomenon that gives sense to the qualitative unity of any substance, consisting the reflex in the ontological act of perception. It is the conceptual key that justifies the use of complex network models to describe systems, which also are complex in nature. Given this key concept, it was desired to apply it on real objects in order to create new analysis methodologies. For this, graph’s theory and random walk’s theory were used as fundamentals for two study cases. One of them consists on an analysis of the mythological social network of Odyssey of Homer. It was found that this network displays structural characteristic of real social network mixed with fictional aspects associated to mythological characters. Another study was the oral tolerance phenomenon modeled as a complex network associated with stochastic dynamics. We applied the random walk as a way to understand the relative importance of each immunological component. Finally, it becomes evidenced that the key concept of emergence allows new forms of analysis using complex network theory as a model which comprises the complexity inherent on the conception of real systems. / A emergência é fenômeno que dá unidade qualitativa a qualquer substância, constituindo o reflexo no ato ontológico da percepção. É a chave conceitual que justifica o uso do modelo em redes complexas para descrever sistemas, que também são complexos naturalmente. Dada essa chave conceitual, buscou-se utilizá-la na geração de novas análises. Para tanto é empregado a teoria de grafos e a caminhada aleatória em dois estudo de caso. Um deles constitui a análise de uma rede mitológica referente à Odisseia de Homero. Foi verificado que a rede mitológica apresenta padrões de redes sociais reais quando excetuados da rede as personagens mitológicas. Em segundo lugar, foi realizado um estudo da tolerância oral como um fenômeno de rede complexa, foi utilizada a caminhada aleatória como modelo estocástico de difusão de estímulos numa rede complexa. Com isso, foi possível conhecer a importância relativa de cada componente imunológica. Por fim, fica evidenciado que o conceito chave de emergência permite a concepção de novas formas de análise, fundamentalmente no uso de redes complexas como modelos que albergam a complexidade inerente na concepção de sistemas reais.

La tolérance orale permet la modulation de la réponse immunitaire à l’égard des antigènes exogènes présents dans la lumière intestinale. Essentiels à l’établissement d’une relation symbiotique entre le système immunitaire et la flore intestinale, l’induction et le maintien de la tolérance orale reposent sur différents mécanismes immunologiques. Parmi eux, l’induction de cellules T régulatrices par les cellules dendritiques et de mécanismes apoptotiques. Or, la glycoprotéine membranaire CD47 est impliquée, en périphérie, dans ces mécanismes. Cependant, le rôle de CD47 dans la tolérance orale n’est pas connu. À l’aide d’un modèle murin déficient en CD47, nous avons démontré principalement, que l’absence de CD47 est associée à une diminution de 50 % de la proportion de cellules dendrites myéloïdes CD11b+CD103- retrouvées dans les ganglions mésentériques. Suite au transfert adoptif de cellules T antigènes spécifiques dans nos différents modèles expérimentaux, on a, aussi, observé une diminution de 45 % de leur niveau d’activation dans les ganglions mésentériques. Malgré les effets observés, le CD47 n’est pas impliqué dans l’induction d’une réaction de tolérance orale secondaire à l’administration intragastrique de fortes doses d’ovalbumine. Cependant, nous avons démontré que CD47 est impliquée au niveau de la migration des cellules dendritiques de la peau et de certaines sous-populations retrouvées dans les ganglions mésentériques. / Oral tolerance allows the modulation of the immune response against exogenous antigens present in the intestinal lumen. Essential to establish a symbiotic relationship between the immune system and intestinal flora, the induction and maintenance of oral tolerance rests on different immunological mechanisms. Among them, induction of regulatory T cells by dendritic cells and apoptotic mechanisms. However, the membrane glycoprotein CD47 is involved in the periphery of these mechanisms. However, the role of CD47 in oral tolerance is unknown. With a mouse model deficient in CD47, we showed mainly that the absence of CD47 is associated with a decrease of 50% in the proportion of myeloid dendritic cells CD11b+ CD103- found in the mesenteric lymph nodes. Following the adoptive transfer of antigen specific T cells in our experimental models, we also observed a decrease of 45% of their level of activation in mesenteric lymph nodes. Despite the observed effects, CD47 is not involved in the induction of oral tolerance response secondary to intragastric administration of high doses of ovalbumin. However, we have shown that CD47 is involved in the migration of dendritic cells of the skin and some sub-populations found in mesenteric lymph nodes.

La tolérance orale permet la modulation de la réponse immunitaire à l’égard des antigènes exogènes présents dans la lumière intestinale. Essentiels à l’établissement d’une relation symbiotique entre le système immunitaire et la flore intestinale, l’induction et le maintien de la tolérance orale reposent sur différents mécanismes immunologiques. Parmi eux, l’induction de cellules T régulatrices par les cellules dendritiques et de mécanismes apoptotiques. Or, la glycoprotéine membranaire CD47 est impliquée, en périphérie, dans ces mécanismes. Cependant, le rôle de CD47 dans la tolérance orale n’est pas connu. À l’aide d’un modèle murin déficient en CD47, nous avons démontré principalement, que l’absence de CD47 est associée à une diminution de 50 % de la proportion de cellules dendrites myéloïdes CD11b+CD103- retrouvées dans les ganglions mésentériques. Suite au transfert adoptif de cellules T antigènes spécifiques dans nos différents modèles expérimentaux, on a, aussi, observé une diminution de 45 % de leur niveau d’activation dans les ganglions mésentériques. Malgré les effets observés, le CD47 n’est pas impliqué dans l’induction d’une réaction de tolérance orale secondaire à l’administration intragastrique de fortes doses d’ovalbumine. Cependant, nous avons démontré que CD47 est impliquée au niveau de la migration des cellules dendritiques de la peau et de certaines sous-populations retrouvées dans les ganglions mésentériques. / Oral tolerance allows the modulation of the immune response against exogenous antigens present in the intestinal lumen. Essential to establish a symbiotic relationship between the immune system and intestinal flora, the induction and maintenance of oral tolerance rests on different immunological mechanisms. Among them, induction of regulatory T cells by dendritic cells and apoptotic mechanisms. However, the membrane glycoprotein CD47 is involved in the periphery of these mechanisms. However, the role of CD47 in oral tolerance is unknown. With a mouse model deficient in CD47, we showed mainly that the absence of CD47 is associated with a decrease of 50% in the proportion of myeloid dendritic cells CD11b+ CD103- found in the mesenteric lymph nodes. Following the adoptive transfer of antigen specific T cells in our experimental models, we also observed a decrease of 45% of their level of activation in mesenteric lymph nodes. Despite the observed effects, CD47 is not involved in the induction of oral tolerance response secondary to intragastric administration of high doses of ovalbumin. However, we have shown that CD47 is involved in the migration of dendritic cells of the skin and some sub-populations found in mesenteric lymph nodes.