As células dendríticas (DCs) são críticas no processo de indução de imunidade e tolerância periférica. Estas células apresentam inúmeros receptores em sua superfície e podem ser classificadas em diferentes subpopulações de acordo com a expressão dos mesmos. Anticorpos monoclonais dirigidos contra diferentes receptores celulares vêm sendo utilizados com sucesso no tratamento de patologias como câncer. Nos últimos dez anos, demonstrou-se que é possível enviar antígenos diretamente para o receptor DEC205 presente na superfície das DCs. Quando isso acontece na ausência de estímulo inflamatório, o resultado é a indução de tolerância imunológica. Quando o antígeno é enviado a estas mesmas células na presença de um estímulo inflamatório, o resultado é a indução de uma forte resposta imunológica. Geramos um anticorpo <font face=\"Symbol\">aDEC205 em fusão com a proteína 2 de superfície dos amastigotas (ASP-2) de Trypanosoma cruzi e estudamos o efeito da administração deste anticorpo in vivo na presença de diferentes adjuvantes em duas linhagens distintas de camundongos. Observamos que ambas as linhagens de camundongos não foram capazes de gerar anticorpos, mas a resposta imune celular foi suficiente para reduzir a parasitemia quando desafiados com tripomastigotas cepa Y de Trypanosoma cruzi. Camundongos A/J foram capazes de mediar apresentação cruzada. Mapeamos um peptídeo que é reconhecido por camundongos BALB/c. Camundongos imunizados com Poly (I:C) como estímulo de maturação mostrou-se superior ao CpG. / As part of the innate immune system, dendritic cells (DCs) are critical in the process of induction of immunity and peripheral tolerance. These cells offer many receptors on their surface and can be classified in different subsets according to the expression there of. Monoclonal antibodies directed against different cellular receptors have been used successfully to treat diseases such as cancer. In the last ten years has been demonstrated that antigen can be sent directly to the receiver DEC205 present on the surface of DCs in vivo. When this happens in the absence of concomitant inflammatory stimulus, the result is the induction of immunological tolerance. Moreover, when the antigen is sent to the same cells in the presence of an inflammatory stimulus, the result is to induce a strong immune response. In this study we generated an antibody <font face=\"Symbol\">aDEC205 fusion protein with the amastigote surface protein 2 (ASP-2) from Trypanosoma cruzi and study the effect of administration of this antibody in vivo in the presence of different adjuvants in two distinct strains of mice. We observed that both strains of mice were unable to generate antibodies, but cellular immune response was sufficient to reduce the parasitemia when challenged with trypomastigotes Y strain of Trypanosoma cruzi. The mice A/J were able to mediate cross-presentation. In contrast, we mapped a peptide that is recognized by BALB/c mice. In counterpart mice immunized with Poly (I:C) as maturation stimuli was superior to CpG.

As células dendríticas (DCs) são fundamentais no desencadeamento da resposta imune antitumoral. Mas, no microambiente tumoral há condições que impedem esta função imunoestimuladora das DCs. Este comprometimento funcional parece ser fruto da hiperativação de STAT-3. O presente estudo visou avaliar a capacidade de Ta1 de interferir na ativação de STAT-3. Então, monócitos e mo-DCs foram tratados ou não com Ta1 e comparados com o controle, o inibidor de STAT-3, JSI-124. Avaliou-se a expressão de moléculas de superfície e a capacidade de mo-DCs de estimular linfócitos T alogeneicos. Ta1 não interferiu na ativação de STAT-3. Além disso, Ta1 não reproduziu os efeitos encontrados em mo-DCs de pacientes com câncer. Já, o tratamento com JSI-124 levou a alterações nas mo-DCs fazendo com que exibissem perfil infamatório, com aumento de HLA-DR, CD86 e concomitante queda de PD-L1. Além disso, mostramos que STAT-3 está envolvido na expressão de leucointergrinas, uma vez que sua inibição proporcionou queda da expressão em nível proteico e gênico destas moléculas. / Dendritic cells ( DCs ) are critical in triggering antitumor immune response . But there are conditions in the tumor microenvironment that prevent this immunostimulatory function of DCs. This functional impairment appears to be the result of hyperactivation of STAT-3. The present study aimed to evaluate the ability of Ta1 to interfere in the activation of STAT-3. Then, monocytes and mo-DCs were treated or not with Ta1 and compared with the control, the STAT-3 inhibitor, JSI -124. We assessed the expression of surface molecules and the mo-DCs ability in stimulating allogeneic T lymphocytes. Ta1 did not affect the activation of STAT-3. In addition, Ta1 did not reproduce the effects found in mo-DCs from cancer patients. However, JSI -124 treatment led to changes in mo-DCs, that exhibited an inflammatory profile, with an increase of HLA-DR , CD86 and concomitant drop in PD- L1. Furthermore, we have shown that STAT-3 is involved in the expression of leukointergrins, since its inhibition resulted in down-regulation of expression level of this gene and protein molecules.

Para serem apresentados pelo MHC I em células dendríticas, os antígenos são processados pelo imunoproteassomo. O objetivo do trabalho foi examinar o efeito de pró-oxidantes em DC para avaliação da proliferação de linfócitos T CD8+, com foco no sistema ubiquitina-proteassomo. Os resultados mostram que o sistema Xantina/Xantina Oxidase aumentou a proliferação de T CD8+ isolados de camundongos imunizados com DNA-HSP65 após a co-cultura destas células com DC tratadas com XaXO. O XaXO promoveu maior maturação de DC em relação ao LPS, assim como uma queda da atividade catalítica do IP, sugerindo que o aumento da proliferação de T CD8+ não está diretamente relacionado à atividade do IP. A incubação de DC com XaXO não alterou a expressão da unidade catalítica 20S, da unidade regulatória 19S ou da subunidade <font face=\"Symbol\">&#9465i. Observou-se aumento da expressão da unidade regulatória 11S e do conteúdo de proteínas ubiquitinadas. Sugere-se que 11S se acoplaria a 20S deslocando 19S, promovendo o acúmulo de proteínas ubiquitinadas e direcionando mais fragmentos para a apresentação antigênica. / To be presented in dendritic cells MHC I, antigens are processed by immunoproteasome. The aim of the study was to examine the effect of pro-oxidants in dendritic cell-induced T CD8+ lymphocyte proliferation with focus on ubiquitin-proteasome system. The co-culture of DC incubated with Xanthine/Xanthine Oxidase system and T CD8+ isolated from mice immunized with DNA-HSP65 promoted T CD8+ proliferation. XaXO incubation was more efficient in promoting DC maturation compared to LPS. In addition, XaXO incubation decreased IP catalytic activity in relation to LPS, suggesting that increased T CD8+ proliferation is not directly related to IP activity. XaXO incubation did not alter the expression of 20S catalytic subunit, 19S regulatory unit or <font face=\"Symbol\">&#9465i subunit. XaXO incubation increased 11S regulatory unit content as well as that of ubiquitinated proteins. We suggest that the DC incubation with XaXO increased 11S content favoring its coupling to 20S in detriment of 19S. This would increase ubiquitinated protein levels and direct more peptide fragments for antigen presentation.

Paracoccidioidomicose é adquirida pela via respiratória e a enzima indolamina-2,3-dioxigenase (IDO) e o catabolismo do triptofano estão envolvidos no controle da imunidade inata e adaptativa contra patógenos. Investigamos o papel da IDO na doença em animais suscetíveis (B10.A) e resistentes (A/J). Caracterizamos o efeito do tratamento com 1-Metil-DL-Triptofano (1MT) no fenótipo e comportamento de células dendríticas (DCs) e T reguladoras (Tregs) de A/J e B10.A quanto à expressão de IDO. IDO controla a carga fúngica de A/J e B10.A, reduzindo a imunidade de TCD4 e TCD8 e aumentando Tregs. Constatamos que IDO diminuiu a migração de DCs para o pulmão de A/J e B10.A e a inibição da atividade anti-inflamatória de IDO por 1MT tem um efeito deletério somente em B10.A cuja suscetibilidade é ligada à excessiva atividade pró-inflamatória. A infecção de A/J e B10.A parece induzir as funções catalítica e sinalizadora de IDO.Grande parte da função de IDO nos mecanismos imunorreguladores na paracoccidioidomicose se faz através da modulação da função de DCs em A/J e B10.A. / Paracoccidioidomycosis is acquired by the respiratory route and the enzyme indoleamine-2,3-dioxygenase (IDO) and tryptophan catabolism are involved in the control of innate and adaptive immunity against pathogens. We investigated the role of IDO in the infection in susceptible (B10.A) and resistant (A/J) mice. We characterized the effect of treatment with 1-Methyl-DL-Tryptophan (1MT) in the behavior and phenotype of dendritic cells (DCs) and regulatory T cells (Tregs) from A/J and B10.A for expression of IDO. IDO controls the fungal load in A/J and B10.A, reducing the immunity of CD4 and CD8 T cells and Tregs increased. IDO decreased the migration of DCs to the lung of A/J and B10.A and inhibition of anti-inflammatory activity of IDO by 1MT has a deleterious effect only in B10.A whose susceptibility is linked to excessive proinflammatory activity. Infection of A/J and B10.A appears to induce catalytic functions of IDO. Much of the function IDO immunoregulatory mechanisms paracoccidioidomycosis is done by modulating the function of DCs in A/J and B10.A.

As células dendríticas (DCs) são as principais células apresentadoras de antígeno do sistema imune, e há evidências da participação na tolerância imunológica. Neste estudo avaliamos as alterações ocorridas na população de células CD4+CD25+Foxp3+ após co-cultura de células de linfonodo com BMDCs, na presença de timócitos alogênicos ou singênicos em apoptose. Após cultura na presença de células alogênicas a população de Tregs mostra-se aumentada, e essa expansão é dependente de contato entre a DC e o linfócito T, já que o isolamento das culturas diminuiu a expressão destes marcadores. A internalização de células em apoptose foi induziu caráter tolerogênico nas DCs com baixa expressão de moléculas co-estimuladoras e resistência à maturação por LPS. As células CD4+CD25+ geradas in vitro foram capazes de conter a proliferação de esplenócitos de camundongos BALB/c estimulados por esplenócitos de C57BL/6 irradiados, anti-CD3 e OVA. No ensaio in vivo, as Tregs geradas in vitro também foram capazes de suprimir a proliferação de células CD25- quando transferidas para animais Nude, impedindo também o infiltrado inflamatório no estômago, cólon, fígado e rins, sendo assim capazes de suprimir a resposta imune in vitro e in vivo. / The dendritic cell (DC) plays a very important role in antigen presentation in the immune system and recent articles have shown the involvement in maintaining peripheral tolerance. Here we evaluated the changes in the CD4+CD25+Foxp3+ after co culture of DCs with lymph node cells. BMDCs were pulsed with apoptotic cells and co-cultured with lymph-node cells. Our results show an increase of CD4+CD25+Foxp3+ T cells after co-culture with DCs pulsed with apoptotic cells. Furthermore, the DCs did not change the pattern of co-stimulatory molecules expression due to phagocytosis of syngeneic or allogeneic apoptotic cells and further stimulation with LPS. The CD4+CD25+ cells sorted from the in vitro culture were able to suppress the proliferation of splenocytes in vitro in a specific and non-specific manner. As expected, the co-transfer of CD4+CD25- and CD4+CD25+, both sorted from the in vitro culture, was able to control the cell infiltrates in the target organs and the total cell count in the lymph-nodes. Thus, the Tregs expanded in vitro are able to suppress the immune response in vitro and in vivo assays.

O veneno da subespécie de cascavel Crotalus durissus terrificus (C.d.terrificus) altera a coagulação, tem ação neurotóxica, miotóxica e efeito imunossupressivo. O veneno de C.d.terrificus e a sua fração majoritária, crotoxina (CTX), inibem a resposta celular e humoral, sendo esse efeito independente da indução de morte celular. O objetivo foi investigar os mecanismos envolvidos na imunossupressão exercida pela CTX. A CTX induz a produção de IL-10, TGF-<font face=\"Symbol\">&#946 e prostaglandina E2 (PGE2) pelas células dos camundongos que a receberam. Menor secreção de IFN-<font face=\"Symbol\">&#947 e IL-12 foi observada nas culturas de células de camundongos imunizados e que receberam CTX. A CTX aumenta a expressão da enzima indoleamina 2,3 dioxigenase e a geração de células T reguladoras em camundongos imunizados com OVA e que receberam CTX. A CTX foi capaz de inibir a expressão de CD40, CD80, CD86 e de MHC de classe II em células de camundongos imunizados e nas células dendríticas (DCs) purificadas destes animais. Em culturas de DCs, a CTX induz alta secreção de IL-10, TGF-<font face=\"Symbol\">&#946 e PGE2 e menor de IL-12. / The venom of the rattlesnake Crotalus durissus terrificus (C.d.terrificus) changes the coagulation system and presents neurotoxic, myotoxic and immunosuppressive effect. The venom and its main fraction, crotoxin (CTX) inhibited both the cellular and humoral response. This effect is not due to induction of cell death. The objective was to investigate the immunosuppressive mechanisms of CTX. CTX induces production of IL-10, TGF-<font face=\"Symbol\">&#946 and prostaglandin E2 (PGE2) by cells of mice that received it. Lower secretion of IFN-<font face=\"Symbol\">&#947 and IL-12 was observed in the cultured cells from mice immunized that received CTX. CTX promotes increased expression of the enzyme indoleamine 2,3 dioxygenase and generation of regulatory T cells in mice immunized with OVA and receiving the toxin. CTX was able to inhibit the expression of CD40, CD80, CD86 and MHC II in mice immunized and in dendritic cells (DCs) purified from these animals. In cultures of DCs, CTX increased secretion of IL-10, TGF-<font face=\"Symbol\">&#946 and PGE 2 and lower IL-12.

Paracoccidioidomicose (PCM), micose sistêmica prevalente na América Latina, é uma doença granulomatosa causada pelo fungo termodimórfico do gênero Paracoccidioides spp. O maior número de casos dessa doença tem sido reportado no Brasil, Colômbia, Venezuela e Argentina. A existência de extensas áreas endêmicas, alto potencial incapacitante devido a fibroses pulmonares, grande quantidade de mortes prematuras, faz com que a PCM seja considerada um grave problema de Saúde Pública. Apesar do tratamento medicamentoso ser relativamente eficiente, o tempo longo de uso das drogas e os efeitos colaterais provocados podem levar a diminuição da adesão ao tratamento diminuindo assim eficácia. O uso de vacinas terapêuticas pode ser uma importante ferramenta no controle da PCM. Uma das modalidades investigadas pelo nosso grupo é a utilização de células dendríticas (DCs) pulsadas com o peptídeo P10 como vacina terapêutica no controle da PCM. Resultados apresentados por nosso grupo, demonstraram que DCs diferenciadas a partir de células de medula óssea de camundongos saudáveis pulsadas com o peptídeo 10 (P10) podem ser utilizadas como adjuvante no tratamento da paracoccidioidomicose experimental em camundongos imunocompetentes e imunossuprimidos. Assim sendo, nossa proposta no presente trabalho foi avaliar se DCs diferenciadas de células de medula óssea (BMDCs) ou de monócitos circulantes (MoDCs) de camundongos (BALB/c) infectados apresentam modulação prévia devido à exposição a antígenos fúngicos, avaliamos in vitro a capacidade das células dendríticas diferenciadas a partir de monócitos circulantes de camundongos infectados com Pb18 estimular proliferação de linfócitos CD8+ e CD4+, analisamos a capacidade de células dendríticas derivadas de monócitos circulantes de camundongos infectados com Pb18 pulsadas com P10 em induzir uma resposta protetora. Nossos resultados obtidos são promissores e reforçam dados já publicados pelo grupo os quais demonstraram a eficiência do peptídeo P10 no tratamento da paracoccidioidomicose experimental; apontam que o P10 é capaz de modular ativamente células dendríticas diferenciadas de monócitos circulantes e diferenciadas de células de medula óssea; demonstram que BMDCs e MoDCs pulsadas ou não com P10 tem a capacidade de estimular proliferação de linfócitos T CD4+ e CD8+; confirmaram que BMDC e MoDCs pulsadas ou não com P10 diminuem a carga fúngica no tecido pulmonar, estimulando um padrão de citocinas misto, porém com predominância de citocinas pró-inflamatórias que incitam resposta imune celular do tipo Th1, que é protetora na PCM. Estes dados foram respaldados com a análise dos cortes histológicos onde os pulmões dos camundongos tratados com BMDCs ou MoDCs pulsadas com P10 apresentaram parênquima pulmonar mais conservado em comparação com os pulmões dos grupos que não receberam tratamento com BMDCs ou MoDCs, com diminuição significativa de células fúngicas viáveis / Paracoccidioidomycosis (PCM), a systemic mycosis prevalent in Latin America, is a granulomatous disease caused by the thermodymorphic fungus of the genus Paracoccidioides spp. The highest number of cases of this disease has been reported in Brazil, Colombia, Venezuela and Argentina. The existence of extensive endemic areas, a high incapacitating potential due to pulmonary fibroses, and a large number of premature deaths, makes the PCM considered a serious public health problem. Although the drug treatment is relatively efficient, the long time of use of the drugs and the side effects provoked can lead to the decrease of the adherence to the treatment thus diminishing their effectiveness. The use of therapeutic vaccines can be an important tool in the control of PCM. One of the modalities investigated by our group is the use of dendritic cells (DCs) pulsed with the peptide P10 as therapeutic vaccine in the control of PCM. Results presented by our group demonstrated that DCs differentiated from bone marrow cells of healthy mice pulsed with peptide 10 (P10) can be used as an adjuvant in the treatment of experimental paracoccidioidomycosis in immunocompetent and immunosuppressed mice. Thus, our proposal in the present study evaluated the capacity of differentiated DCs of bone marrow cells (BMDCs) or circulating monocytes (MoDCs) of infected mice (BALB/c) exhibited previous modulation due to exposure to fungal antigens, we evaluated in vitro the ability of differentiated dendritic cells from circulating monocytes from Pb18 infected mice to stimulate proliferation of CD8+ and CD4+ lymphocytes, we analyzed the ability of dendritic cells derived from circulating monocytes from mice infected with P. brasiliensis pulsed with P10 to induce a protective response. Our results are promising and reinforce data already published by the group which demonstrated the efficiency of the peptide P10 in the treatment of experimental paracoccidioidomycosis; suggest that P10 is capable of actively modulating differentiated dendritic cells from circulating and differentiated monocytes from bone marrow cells; demonstrate that BMDCs and MoDCs pulsed or not with P10 have the ability to stimulate proliferation of CD4+ and CD8+ T lymphocytes; confirmed that BMDC and MoDCs pulsed or not with P10 decrease the fungal load in lung tissue, stimulating a pattern of mixed cytokines but with a predominance of pro-inflammatory cytokines that stimulate Th1-type cellular immune response that is protective in PCM, these data were supported with analysis of the histological sections where the lungs of the mice treated with BMDCs or MoDCs pulsed or not with P10 showed more conserved pulmonary parenchyma compared to the lungs of the groups that did not receive treatment with BMDCs or MoDCs, with significant decrease of viable fungal cells

Nous avons découvert que les DC pathologiques (LCH DC) qui s’accumulent dans les granulomes de patients atteints d’histiocytose langerhansienne (LCH) produisent l’IL-17A (Coury et al, Nat Med 2008). In vitro, les LCH DC fusionnent en cellules géantes (MGC) sous l’influence de leur production autocrine d’IL-17A. In vivo, les granulomes de LCH DC et MGC détruisent les tissus. Pendant la thèse, nous avons étudié les transcriptomes des monocytes, DC, traitées ou non par l’IL-17A et des LCH DC. L’IL-17A induit BCL2A1, un membre de la famille Bcl-2 qui prolonge la survie des DC. Elle induit aussi les chémokines CCL20 et CCL2, qui regroupent les DC avant leur fusion. L’induction du récepteur nucléaire LXR-α, de protéines impliquées dans le métabolisme, le transport et le stockage des lipides témoignent d’un profond remodelage lipidique. Après la confirmation de ces régulations par PCR et western, les goutelettes lipidiques sont quantifiées à l’huile rouge, puis l’analyse lipidomique révèle l’augmentation de phospholipides, triglycérides, esters de cholestérol et cholestérol par l’IL-17A dans les DC qui sont aussi capables de capturer du palmitate extracellulaire fluorescent. Les transcriptomes des DC traitées à l’IL-17A et des LCH DC sont similaires. La simvastatine qui bloque la synthèse de cholestérol tue les LCH DC. Ce travail établit pour la première fois que l’IL-17A affecte profondément le métabolisme lipidique des DC, une activité qui pourrait avoir d’importantes applications dans les maladies chroniques inflammations associées à une dérégulation lipidique comme l’athérosclérose, l’obésité, la tuberculose et la LCH / We found that the pathological DCs (DC LCH), accumulating in the granulomas of patients affected with Langerhans cell histiocytosis (LCH), produce IL-17A (Coury et al, Nat Med 2008). In vitro, LCH DCs form multinucleated giant cells (MGC) by a fusion process, under the influence of their IL-17A autocrine production. In vivo, granulomas, which are mainly composed of LCH DCs and MGCs, destroy tissues of the patients. During the PhD, we studied the transcriptomes of monocytes, DCs, treated or not with IL-17A, and LCH DCs. IL-17A induceed BCL2A1, a member of the Bcl-2 family that prolonged DC survival. It also induced the CCL2 and CCL20 chemokines that clustered DC, a process required to license DC fusion. The inductions of LXR-α nuclear receptors, proteins involved in metabolism, transport and storage of lipids signed a deep lipid remodeling induced by IL-17A in DCs. We confirmed these regulations by PCR and western studies, then the lipid droplets were quantified after Oil Red-O staining. Further lipidomic analysis revealed an increase of phospholipids, triglycerides, cholesteryl esters and cholesterol by IL-17A in DCs, which are also able to capture extracellular fluorescent palmitate. Transcriptomes of DCs treated with IL-17A and LCH DCs were similar. Simvastatin, which inhibits the synthesis of cholesterol, killed LCH DC. For the first time, this work establishes that IL-17A profoundly affects the lipid metabolism of DCs, an activity that may have important applications in chronic inflammations associated with lipid deregulations such as atherosclerosis, obesity, tuberculosis and LCH

Une fois activées, les cellules dendritiques (DCs) migrent dans les organes lymphoïdes ou elles exercent leur rôle de cellules présentatrices d’antigène professionnelles. Elles sont capables d’activer et d’induire la différenciation des lymphocytes T naïfs en différentes sous-populations de lymphocytes T auxiliaires. L’ajustement de la réponse lymphocytaire T au type d’inflammation est assuré par les DCs à deux niveaux. Premièrement, grâce à leur plasticité, les DCs adaptent leur comportement en fonction de la combinaison de signaux issus du microenvironnement inflammatoire. Deuxièmement, il existe différentes sous-populations de cellules dendritiques ayant de différentes spécialisations fonctionnelles.Mon travail de thèse s’est concentré sur l’étude de la diversité des réponses des sous-populations de cellules dendritiques humaines suite à la stimulation par la cytokine lymphopoïetine stromale thymique (TSLP). Cette cytokine est secrétée par les cellules épithéliales et la peau au cours de l’inflammation. La TSLP active principalement les DCs myéloïdes, induisant celles-ci à secréter les chimiokines inflammatoires CCL17 et CCL22. Les DCs activées par la TSLP (TSLP-DCs) induisent une réponse inflammatoire de type Th2, et sont impliquées dans le développement de l’allergie. La comparaison systématique de la réponse à la TSLP par les sous-populations de DCs du sang, BDCA1+ et BDCA3+, nous a permis de montrer que ces deux sous-populations sont activées par la TSLP. Toutefois, nos résultats montrent que la TSLP, en synergie avec le TGF-β, induit la différenciation des DCs BDCA-1+ en cellules de Langerhans, mais pas celle des DCs BDCA-3+. De plus, la TSLP induit la migration cellulaire et la sécrétion de chimiokines seulement chez la sous-population de DCs BDCA-1+. Des analyses complémentaires des mécanismes impliqués dans la migration des DCs BDCA-1+ en réponse à la TSLP révèlent que, d’une part la TSLP est indispensable à l’induction de la migration et d’autre part, qu’un récepteur de chimiokines, sensible à la Toxine Pertussique serait impliqué. Au final, nos résultats révèlent (i) de nouvelles capacités des DCs en tant que cellules précurseurs, (ii) de différentes propriétés fonctionnelles des sous-populations de DCs en réponse à la stimulation par la TSLP, (iii) et démontrent la complexité des mécanismes impliqués dans la migration des DCs induite par la TSLP. / Once activated, Dendritic Cells (DCs) migrate to the lymphoid organs and exert their role as professional antigen presenting cells. They are able to induce the activation and differentiation of naïve T cells into different types of T helper cells. The T cell response must be suited to the type of inflammation. This is ensured by DCs at two levels. First DCs are functionally plastic. This means that their behavior is subdued to the integrated signals coming from the inflammatory microenvironment. Secondly, the DC population is diverse. Indeed, different DC subsets have different functional specializations. My thesis was focused on the differential response of human DC subsets to Thymic stromal lymphopoietin (TSLP). This cytokine is secreted by inflamed skin and epithelia, and strongly activates myeloid DCs. The TSLP-activated DCs secrete the inflammatory chemokines CCL17 and CCL22, prime an inflammatory Th2 response, and have been involved in the pathogenesis of allergic inflammation. By systematically comparing the response of human blood BDCA-1+ and BDCA-3+ DCs to TSLP stimulation we found that both of these DC subsets get activated by TSLP. However TSLP synergizes with TGF-β to induce the differentiation of blood BDCA-1+ and not BDCA-3+ DCs into Langerhans Cells. Moreover, TSLP induces cell migration and chemokine secretion only on the blood BDCA-1+ subset. Further analysis of the mechanisms implicated in TSLP-induced DC migration revealed that TSLP is required to induce DC migration, but this effect is dependent on the expression of a PTX-sensitive chemokine receptor. Overall our results reveal new precursor capacities of blood DC subsets, different functional properties of blood DC subsets stimulated by TSLP and highlight intricate mechanisms underlying TSLP-induced DC migration.

Este trabalho objetivou avaliar os efeitos imunomoduladores das células-tronco imaturas da polpa dentária (CTIPD) sobre a diferenciação, maturação das células dendríticas derivadas de monócitos (mo-DC), sua capacidade para ativar linfócitos T (Lin T), bem como verificar fatores solúveis liberados nos cocultivos celulares. As analises foram feitas por citometria de fluxo. Foi observado que mo-DC tiveram a diminuição de moléculas relacionadas à diferenciação para mo-DC e o aumento de moléculas relacionados ao estado precursor, o que parece ter refletido na maturação para mDC, verificado pela diminuição das moléculas de maturação. As mo-DC tiverem sua função em induzir a proliferação de Lin T reduzida, além, de favorecer o aumento da proporção de Lin T CD4+FoxP3+IL-10+ e Lin T CD4+FoxP3+IFN-<font face=\"Symbol\">g+. A mensuração dos fatores solúveis dos cocultivos mostrou que houve aumento de fatores anti-inflamatórios e redução de fatores pró-inflamatórios. Futura investigações podem suportar o uso das CTIPD em uma abordagem imunomoduladora utilizando DC em aplicações clínicas. / This study aimed to evaluate the immunomodulatory effects of immature stem cells from dental pulp on differentiation, maturation of monocyte-derived dendritic cells (mo-DC), their ability to activate T cells, as well as identify soluble factors released in cellular cocultures. The analyzes were performed by flow cytometry. It was observed a decrease of molecules related to mo-DC differentiation and an increase of molecules related to precursor state, which seems to have reflected to mDC maturation verified by reduction of maturation molecules. The mo-DC have their role in inducing T cells proliferation reduced, in addition, favored increase CD4+FoxP3+IL-10+ and CD4+FoxP3+IFN-<font face=\"Symbol\">g+ T cells population proportion. The measurement of soluble factors from coculture showed an increase of anti-inflammatory factors and a reduction of pro-inflammatory factors. Future research may support the use immature stem cells from dental pulp in an immunomodulatory approach using DC in clinical applications.