No description available.

No description available.

No description available.

During the course of an immune response, CD4+ T helper cells differentiate into a number of subsets including: T helper 1 (TH1), TH2, TH17, and T follicular helper (TFH) populations. The functional diversity of CD4+ T effector cells results in a coordinated, pathogen-specific immune response. For example, the production of IFNγ by TH1 cells is vital for the clearance of intracellular pathogens, while TFH cell engagement with cognate B cells is required for germinal center (GC) formation and the generation of pathogen- and vaccine- induced antibody production. The development of CD4+ subsets is contingent on extracellular signals, in the form of cytokines, and downstream transcriptional networks responsible for promoting the unique gene expression profile for each subset while simultaneously suppressing alternative cell fates. However, the exact composition of, and stage-specific requirements for, these environmental cytokines and transcription factor networks in the governance of TFH cell differentiation remain incompletely understood. The work in this dissertation seeks to understand how cell-extrinsic cytokine signals and cell-intrinsic transcription factor activities are integrated to properly regulate TFH cell development. Here, we demonstrate that in response to decreased IL-2 and constant IL-12 signaling, T helper 1 (TH1) cells upregulate a TFH-like phenotype, including expression of the TFH lineage defining transcription factor Bcl-6. Intriguingly, our work established that signals from IL-12 were required for both the differentiation and function of this TFH-like population. Mechanistically, IL-12 signals are propagated through both STAT3 and STAT4, leading to the upregulation of the TFH associated genes Bcl6, Il21, and Icos, correlating with increased B cell helper activity. Conversely, exposure of these TFH-like cells to IL-7 results in the STAT5-dependent repression of Bcl-6 and subsequent inhibition of the TFH phenotype. Finally, we describe a novel regulatory mechanism wherein STAT3 and the Ikaros zinc finger transcription factors Ikaros and Aiolos cooperate to regulate Bcl-6 expression in these TFH-like cells. Collectively, the work in this dissertation 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. / Ph. 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.

O objetivo deste trabalho foi analisar o comportamento das interleucinas 12 (IL- 12) e 18 (IL-18) em pacientes com endometriose pélvica comparando-as a pacientes de um grupo controle com sintomas sugestivos de endometriose e ausência comprovada da doença. Avaliamos, também, as dosagens das referidas interleucinas em relação à fase do ciclo menstrual, quadro clínico, local da doença, estadiamento e classificação histológica. PACIENTES E MÉTODOS: Foram avaliadas 105 pacientes entre 18 e 40 anos submetidas à videolaparoscopia, ; divididas em 2 grupos: 72 pacientes com endometriose e 33 controles. Colheu-se sangue periférico e fluido peritoneal no intra-operatório e procedeu-se a avaliação das interleucinas, relacionando-se as dosagens entre o grupo controle e o grupo com endometriose e também entre os parâmetros já mencionados. Dividimos as pacientes segundo a fase do ciclo menstrual, o quadro clínico, o local de maior gravidade da doença (peritoneal, ovariana ou profunda), o estadiamento e a classificação histológica. As dosagens das interleucinas foram feitas através do método de ELISA e a análise estatística pela aplicação dos testes Kruskal-Wallis e Dunn. RESULTADOS: A média das dosagens da IL-12 no fluido peritoneal foi significativamente maior nas pacientes com endometriose (82,37 +/- 16,61 pg/mL) que no grupo controle (29,20 +/- 10,21pg/mL), p < 0,001. Não houve diferenças significativas na comparação das dosagens séricas de IL-12 entre pacientes e grupo controle. As médias das dosagens da IL-12 no sangue de pacientes com endometriose avançada foi significativamente mais elevada (196,74 +/- 33,71 pg/mL) que aquela de pacientes com doença inicial (82,04 +/- 16,63 pg/mL), p = 0,007. Não houve diferenças significativas entre as dosagens de IL-18 no sangue e no fluido peritoneal de pacientes e grupo controle, nem em relação à comparação entre doença inicial e doença avançada. As médias das dosagens de IL-12 no fluido peritoneal foram mais elevadas em pacientes com endometriose com dismenorréia severa/incapacitante (82,21 +/- 20,54 pg/mL; p = 0,02), dispareunia de profundidade (101,62 +/- 29,25 pg/mL; p = 0,02) e dor acíclica (101,93 +/- 26,14 pg/mL; p = 0,02). As médias das dosagens de IL-18 no sangue foram mais elevadas em pacientes com endometriose com dismenorréia severa/incapacitante (77,59 +/- 16,50 pg/mL; p = 0,01) e dispareunia de profundidade (61,34 +/- 14,05 pg/mL; p = 0,03). Não houve diferenças significativas entre as dosagens de IL-12 e IL-18, no sangue ou no fluido peritoneal, de acordo com a localização da doença (peritônio, ovário ou doença profunda). Não houve diferenças significativas entre as dosagens de IL-12 e IL- 18, no sangue ou no fluido peritoneal, de acordo com a classificação histológica da doença (estromal, bem-diferenciada, padrão misto de diferenciação e indiferenciada). CONCLUSÕES: A interleucina 12 esteve aumentada no fluido peritoneal de pacientes com endometriose, e no sangue nos estádios avançados da doença. Não houve diferenças nas dosagens da interleucina 18 no sangue ou fluido peritoneal na endometriose em relação a mulheres sem a doença. / The aim of this work was to evaluate the behavior of interleukines 12 (IL-12) and 18 (IL-18) in patients with pelvic endometriosis comparing them with a control group that presented suggestive symptoms of endometriosis and proven absence of the disease, evaluating, also, the levels of the interleukines in relation to the phase of menstrual cycle, clinical symptoms, primary location, disease stage and histological classification. PATIENTS AND METHODS: 105 patients aging from 18 to 40 years have been submitted to the laparoscopic surgery and classified in 2 groups: 72 patients with endometriosis and 33 controls. Peripheral blood and peritoneal fluid were extracted and interleukins were evaluated, correlating the levels between the control group and the group with endometriosis, and also between the parameters previously mentioned. Patients were grouped according to the phase of the menstrual cycle, clinical symptoms, primary location, disease stage and histological classification. Interleukin levels have been measured by ELISA . Statistical analysis was performed by the application of Kruskal-Wallis and Dunn tests. RESULTS: Average levels of IL-12 in the peritoneal fluid was significantly higher in patients with endometriosis (82,37 +/- 16.61 pg/mL) when compared to the control group (29,20 +/- 10,21pg/mL), p < 0,001. No significant differences were found in the comparison of the serum levels of IL-12 between patients and control group.) Average levels of IL-12 in blood of patients with advanced endometriosis were significantly increased (196,74 +/- 33.71 pg/mL) when compared to patients with initial disease (82,04 +/- 16,63 pg/mL), p = 0,007. There were no significant differences between the levels of IL-18 in blood and in peritoneal fluid of patients and control group, nor between patients with initial disease and advanced disease. Average levels of IL-12 in peritoneal fluid were higher in patients with endometriosis with complaints of severe / incapacitating dysmenorrhea (82.21 +/- 20,54 pg/mL; p = 0,02), deep dyspareunia (101,62 +/- 29,25 pg/mL; p = 0,02) and acyclic pain (101,93 +/- 26,14 pg/mL; p = 0,02). Average levels of IL-18 in the blood were higher in patients with endometriosis and severe /incapacitating dysmenorrhea (77,59 +/- 16,50 pg/mL; p = 0,01) and deep dyspareunia (61,34 +/- 14,05 pg/mL; p = 0,03). There were no significant differences between the levels of IL-12 and IL-18, in blood or in peritoneal fluid, according to the primary location of the disease (peritoneal, ovarian or deep infiltrative disease). No significant differences were found between the levels of IL-12 and IL-18, in blood or peritoneal fluid, in accordance to the histological classification of the disease (estromal, well-differentiated, combined standard of differentiation and undifferentiated). CONCLUSIONS: Interleukin 12 wss increased in peritoneal fluid of patients with endometriosis, and in blood in advanced stages of the disease. There were no differences in the levels of interleukin 18 in blood or peritoneal fluid in endometriosis compared to women without the disease.

O objetivo deste trabalho foi analisar o comportamento das interleucinas 12 (IL- 12) e 18 (IL-18) em pacientes com endometriose pélvica comparando-as a pacientes de um grupo controle com sintomas sugestivos de endometriose e ausência comprovada da doença. Avaliamos, também, as dosagens das referidas interleucinas em relação à fase do ciclo menstrual, quadro clínico, local da doença, estadiamento e classificação histológica. PACIENTES E MÉTODOS: Foram avaliadas 105 pacientes entre 18 e 40 anos submetidas à videolaparoscopia, ; divididas em 2 grupos: 72 pacientes com endometriose e 33 controles. Colheu-se sangue periférico e fluido peritoneal no intra-operatório e procedeu-se a avaliação das interleucinas, relacionando-se as dosagens entre o grupo controle e o grupo com endometriose e também entre os parâmetros já mencionados. Dividimos as pacientes segundo a fase do ciclo menstrual, o quadro clínico, o local de maior gravidade da doença (peritoneal, ovariana ou profunda), o estadiamento e a classificação histológica. As dosagens das interleucinas foram feitas através do método de ELISA e a análise estatística pela aplicação dos testes Kruskal-Wallis e Dunn. RESULTADOS: A média das dosagens da IL-12 no fluido peritoneal foi significativamente maior nas pacientes com endometriose (82,37 +/- 16,61 pg/mL) que no grupo controle (29,20 +/- 10,21pg/mL), p < 0,001. Não houve diferenças significativas na comparação das dosagens séricas de IL-12 entre pacientes e grupo controle. As médias das dosagens da IL-12 no sangue de pacientes com endometriose avançada foi significativamente mais elevada (196,74 +/- 33,71 pg/mL) que aquela de pacientes com doença inicial (82,04 +/- 16,63 pg/mL), p = 0,007. Não houve diferenças significativas entre as dosagens de IL-18 no sangue e no fluido peritoneal de pacientes e grupo controle, nem em relação à comparação entre doença inicial e doença avançada. As médias das dosagens de IL-12 no fluido peritoneal foram mais elevadas em pacientes com endometriose com dismenorréia severa/incapacitante (82,21 +/- 20,54 pg/mL; p = 0,02), dispareunia de profundidade (101,62 +/- 29,25 pg/mL; p = 0,02) e dor acíclica (101,93 +/- 26,14 pg/mL; p = 0,02). As médias das dosagens de IL-18 no sangue foram mais elevadas em pacientes com endometriose com dismenorréia severa/incapacitante (77,59 +/- 16,50 pg/mL; p = 0,01) e dispareunia de profundidade (61,34 +/- 14,05 pg/mL; p = 0,03). Não houve diferenças significativas entre as dosagens de IL-12 e IL-18, no sangue ou no fluido peritoneal, de acordo com a localização da doença (peritônio, ovário ou doença profunda). Não houve diferenças significativas entre as dosagens de IL-12 e IL- 18, no sangue ou no fluido peritoneal, de acordo com a classificação histológica da doença (estromal, bem-diferenciada, padrão misto de diferenciação e indiferenciada). CONCLUSÕES: A interleucina 12 esteve aumentada no fluido peritoneal de pacientes com endometriose, e no sangue nos estádios avançados da doença. Não houve diferenças nas dosagens da interleucina 18 no sangue ou fluido peritoneal na endometriose em relação a mulheres sem a doença. / The aim of this work was to evaluate the behavior of interleukines 12 (IL-12) and 18 (IL-18) in patients with pelvic endometriosis comparing them with a control group that presented suggestive symptoms of endometriosis and proven absence of the disease, evaluating, also, the levels of the interleukines in relation to the phase of menstrual cycle, clinical symptoms, primary location, disease stage and histological classification. PATIENTS AND METHODS: 105 patients aging from 18 to 40 years have been submitted to the laparoscopic surgery and classified in 2 groups: 72 patients with endometriosis and 33 controls. Peripheral blood and peritoneal fluid were extracted and interleukins were evaluated, correlating the levels between the control group and the group with endometriosis, and also between the parameters previously mentioned. Patients were grouped according to the phase of the menstrual cycle, clinical symptoms, primary location, disease stage and histological classification. Interleukin levels have been measured by ELISA . Statistical analysis was performed by the application of Kruskal-Wallis and Dunn tests. RESULTS: Average levels of IL-12 in the peritoneal fluid was significantly higher in patients with endometriosis (82,37 +/- 16.61 pg/mL) when compared to the control group (29,20 +/- 10,21pg/mL), p < 0,001. No significant differences were found in the comparison of the serum levels of IL-12 between patients and control group.) Average levels of IL-12 in blood of patients with advanced endometriosis were significantly increased (196,74 +/- 33.71 pg/mL) when compared to patients with initial disease (82,04 +/- 16,63 pg/mL), p = 0,007. There were no significant differences between the levels of IL-18 in blood and in peritoneal fluid of patients and control group, nor between patients with initial disease and advanced disease. Average levels of IL-12 in peritoneal fluid were higher in patients with endometriosis with complaints of severe / incapacitating dysmenorrhea (82.21 +/- 20,54 pg/mL; p = 0,02), deep dyspareunia (101,62 +/- 29,25 pg/mL; p = 0,02) and acyclic pain (101,93 +/- 26,14 pg/mL; p = 0,02). Average levels of IL-18 in the blood were higher in patients with endometriosis and severe /incapacitating dysmenorrhea (77,59 +/- 16,50 pg/mL; p = 0,01) and deep dyspareunia (61,34 +/- 14,05 pg/mL; p = 0,03). There were no significant differences between the levels of IL-12 and IL-18, in blood or in peritoneal fluid, according to the primary location of the disease (peritoneal, ovarian or deep infiltrative disease). No significant differences were found between the levels of IL-12 and IL-18, in blood or peritoneal fluid, in accordance to the histological classification of the disease (estromal, well-differentiated, combined standard of differentiation and undifferentiated). CONCLUSIONS: Interleukin 12 wss increased in peritoneal fluid of patients with endometriosis, and in blood in advanced stages of the disease. There were no differences in the levels of interleukin 18 in blood or peritoneal fluid in endometriosis compared to women without the disease.

Ulm, Univ., Diss., 2008.

Orientador: Alba Regina Monteiro Souza Brito / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-13T17:46:56Z (GMT). No. of bitstreams: 1 Suzuki_Erika_M.pdf: 1238383 bytes, checksum: 353bc5b6bc7ca1900b57457d72dcaaf3 (MD5) Previous issue date: 2008 / Resumo: As Doenças Inflamatórias Intestinais (DII), que englobam a Doença de Crohn (DC) e a Retocolite Ulcerativa Inespecífica (RCUI), representam um grande problema para a saúde, uma vez que um único tipo de tratamento com corticosteróides, imunomoduladores ou anti-TNF-a não é eficaz para manter as remissões. Além disso, esses medicamentos possuem efeitos colaterais e o custo do tratamento é elevado. O número de pessoas que desenvolvem as DII está aumentando substancialmente; isso se deve, principalmente, a fatores genéticos e, secundariamente, a fatores ambientais como alimentação, fumo, fármacos, estresse e a flora comensal. As DII são consideradas superexpressões do sistema imune, que levam ao ataque do trato gastrointestinal do próprio hospedeiro. Nesse contexto, fibras alimentares (FA) são indicadas como adjuvantes no tratamento das DII. Esse estudo teve como objetivo investigar o efeito protetor e/ou terapêutico das FA de abóbora na prevenção da inflamação intestinal induzida por TNBS em ratos. As fibras solúveis, ao serem fermentadas pelas bactérias intestinais anaeróbicas, produzem ácidos graxos de cadeia curta (AGCC) entre outras substâncias. AGCC são de elevada importância nas DII, principalmente o butirato, por fornecer energia aos enterócitos, permitindo o crescimento e a rápida recuperação dos tecidos lesionados. Além disso, as FA de abóbora possuem efeito antioxidante e antiinflamatório, são de fácil acesso aos consumidores e seu custo é baixo. Para a escolha da proporção de FA que mais produziu butirato, foi realizado o teste in vitro, onde diferentes proporções de FA de polpa e semente de abóbora foram incubadas com bactérias anaeróbicas intestinais; os AGCC foram quantificados por Cromatografia de Exclusão de Íons. Durante 23 dias os ratos, do grupo tratado, foram suplementados com FA na proporção 0,1 g de polpa + 0,4 g de semente de abóbora/kg/dia. No 16º dia foi realizada a indução da inflamação intestinal por TNBS e no 24º dia, a eutanásia. Os 8 cm finais do intestino grosso foram coletados para a dosagem de algumas enzimas antioxidantes, atividade da mieloperoxidase e níveis de interleucina 12. Os dados obtidos neste trabalho foram: aumento estatisticamente significativo dos níveis de Peroxidação Lipídica no grupo não-tratado (2,8 ± 1,2 pmol/mg proteína) comparado ao grupo tratado com FA (1,8 ± 0,6 pmol/mg proteína); aumento estatisticamente significativo da infiltração de neutrófilos e macrófagos no grupo não-tratado (35,8 ± 11 U/g proteína) comparado ao grupo tratado com FA (17,6 ± 2,6 U/g proteína); e aumento estatisticamente significativo da interleucina 12 no grupo não-tratado (102,2 ± 42 pg/mL) comparado ao grupo tratado com FA (45,7 ± 9,2 pg/mL). Assim, as FA de abóbora podem ser consideradas fortes candidatas como adjuvantes no tratamento das inflamações intestinais por possuírem um forte potencial antiinflamatório no cólon / Abstract: Crohn's Disease (CD) and Ulcerative Colitis (UC) are known as Inflammatory Bowel Disease (IBD). They are considered a large problem in the health, because the therapy using corticosteroids, immunomodulators and anti-TNF-a are not totally efficient to maintain the remission. Also, they offer many side effects and the treatment cost is high. The number of patients with IBD is increasing. IBD is mainly due to genetic factors and secondary to environmental factors, such as diet, smoking, stress, and comensal flora. IBD is the overexpression of immune system, leading to the gastrointestinal tract injury. In this context, dietary fibers (DF) are suggested to help IBD therapies. The aim of this work was investigate the potential protector and/or therapeutic effects of pumpkin DF in TNBS-induced intestinal inflammation in rats. Soluble fibers are fermented by anaerobical bacteria from intestine and produce short-chain fatty acids (SCFA) among others substances. These SCFA have a lead role, mainly butyrate. Butyrate supply energy for the enterocytes, and helps injured tissues development and recuperation. Pumpkin DF have antioxidant and anti-inflammatory effects also. Pumpkin is sold almost everywhere and is cheap. To choose pumpkin DF mixture that produces high amount of butyrate, an in vitro test was realized. In this test, different pumpkin pulp/seeds mixture were incubated with anaerobical intestinal bacteria. SCFA were quantified by Ion Exclusion Chromatography. The rats of the treated group were supplemented with 0.1 g of pulp + 0.4 g of seeds/kg/day during 23 days. The intestinal inflammation was induced by TNBS on 16th day and the euthanasia was realized on 24th day. The colon latest 8 cm were removed from the rats for some antioxidants enzyme analysis, myeloperoxydase activity and interleukin 12 levels. The results suggest a good anti-inflammatory and antioxidant effect of this DF in the colon. The non-treated group (2.8 ± 1.2 pmol/mg protein) had the lipid peroxidation levels increased significantly compared to treated group (1.8 ± 0.6 pmol/mg protein). The non-treated group (35.8 ± 11 U/g protein) also had the neutrophils and macrophage infiltration increased significantly compared to treated group (17.6 ± 2.6 U/g protein). And finally, the non-treated group (102.2 ± 42 pg/mL) had the interleukin 12 levels increased significantly compared to treated group (45.7 ± 9.2 pg/mL). Thus, pumpkin DF may considered good to help usual intestinal inflammation therapies / Mestrado / Mestre em Farmacologia

Orientador: Ricardo de Lima Zollner / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-09T02:29:32Z (GMT). No. of bitstreams: 1 Perroud_AnaPauladeAlmeidaSalles_M.pdf: 4222371 bytes, checksum: 5ff171cf192f89e5602e731098f85f66 (MD5) Previous issue date: 2005 / Resumo: Duas variantes do Walker 256 foram descritas como Walker 256 A e AR. A variante A é mais agressiva e pode induzir os efeitos sistêmicos como anorexia, retenção de sódio, líguido de perda de peso e morte. Os mecanismos envolvidos na regressão e progressão tumoral são desconhecidos. No presente trabalho, células esplênicas e tumorais de animais inoculados com variantes A e Ar foram isoladas para avaliar a expressão gênica de TGF-ß, IL-12, TNF-a e IFN-? e componentes de apoptose relacionando com anemia, perda de peso, peso do baço, peso do tumor e fragilidade osmótica comparando controles inoculados com Ringer Lactato. Os resultados mostraram que o grupo inoculado com a variante A comparado com a variante Ar, apresenta altos níveis de expressão de TGF-ß em ambas as células esplênicas e tumorais, ausência de expressão de IFN-? e aumento progressivo dos níveis de IL-12 sem infiltrado inflamatório. Esses resultados sugerem que a agressividade da variante A está relacionada á modulação de citocinas, facilitando o crescimento e escape tumoral. A IL-12 pode ser constitutiva nas linhagens A e Ar. A expressão gênica de Bcl-2 foi progressiva e não houve expressão de Fas nas células tumorais do grupo A. Estes resultados demonstram que na linhagem A a imumogenicidade ocorre por outros mecanismos. A expressão de citocinas e componentes de apoptose pode explicar as diferenças das linhagens A e Ar / Abstract: Two variants of this Walker 256 tumor have been previously reported as Walker 256 A and variant Ar. The variant A is more aggressive and can induce systemic effects as anorexia, sodium and water retention, followed by weight loss and death. The mechanisms involved in enhancing tumor regression and progression in this model is still incompletely understood. In the present study, spleen cells and tumor cells from animals inoculated with variants A and AR, were isolated to investigate the TGF-ß, IL-12, IFN-?, TNF-a gene expression, components of apoptosis and relationship with anemia, weight of animals, weight of spleen, height of tumor and osmotic fragility compared with controls inoculated with Ringer Lactate. Results demonstrate that the group inoculated with variant A compared with variant Ar, shows high levels of TGF-ß gene expression in both tumor tissue and spleen cells, no expression of IFN-? and a progressive and higher levels of IL-12 in tumor tissue without inflammatory infiltrate. These results suggest that the aggressively of variant A is relate to cytokine modulation, facilitating the growth and escape of tumor cells. Furthermore, IL-12 seems to be constitutively expressed in both tumor lineage A and AR. The mRNA expression of Bcl-2 was progressive and there is no expression of Fas on tumoral cells of group A. These results demonstrate that on the lineage A the immunogenicity occurs by others mechanisms. The expression of cytokines and components of apoptosis can explain the differences of lineages A and AR / Mestrado / Clinica Medica / Mestre em Clinica Medica

nÃo hà / A ativaÃÃo das cÃlulas do sistema imunolÃgico à modulada atravÃs dos sinais acionados por uma diversidade de receptores de superfÃcie celular, incluindo os receptores ativadores, receptores coestimuladores e receptores inibidores. Receptores relacionados à molÃcula sinalizadora na ativaÃÃo do linfÃcito (SLAM) tÃm influÃncia na ativaÃÃo imunolÃgica celular. Neste trabalho, investigou-se a funÃÃo de SLAM na resposta imunolÃgica à Leishmania braziliensis, e se a resposta de indivÃduos alto (AP) ou baixo (BP) produtores de IFN-&#947; seria modulada pela via de sinalizaÃÃo SLAM. CÃlulas monocucleadas do sangue perifÃrico (CMSP) de 43 indivÃduos foram bloqueadas com &#945;-SLAM, rIFN-&#947;, rIL-12 e fitohemaglutinina, apÃs estimulaÃÃo com L. brazilensis. Verificou-se que L. braziliensis promoveu uma significante reduÃÃo da expressÃo de SLAM nas cÃlulas T, com 120h de cultivo, possivelmente indicando ativaÃÃo desta via na resposta imunolÃgica inicial. A expressÃo de SLAM se comportou de modo diferenciado nos indivÃduos AP e BP. Nos indivÃduos BP, L. braziliensis nÃo alterou a expressÃo de SLAM nas cÃlulas T, na fase inicial da resposta imunolÃgica. O bloqueio da via de SLAM com &#945;-SLAM reduziu significativamente a expressÃo desta proteÃna nos primeiros momentos da resposta imunolÃgica das CMSP estimuladas com L. braziliensis. O bloqueio com &#945;-SLAM, avaliado com 120 horas, nÃo alterou a expressÃo de CD3+SLAM+, em ambos os grupos. As citocinas proinflamatÃrias, rIFN-&#947; e rIL-12, presentes no microambiente com L. braziliensis, reduziram a expressÃo de SLAM apenas em indivÃduos AP com 6h de sensibilizaÃÃo e nÃo modificaram esta resposta com 120h de cultivo, na presenÃa do antÃgeno. O bloqueio com &#945;-SLAM, na concentraÃÃo de 10&#956;g/ml, nÃo interferiu na produÃÃo das citocinas IFN-&#947; e IL-13, em ambos os grupos, entretanto aumentou de forma significativa a produÃÃo de IL-10 em indivÃduos AP. O bloqueio da via de SLAM associado à L. braziliensis e rIFN-&#947; nÃo modificou a produÃÃo de IFN-&#947;, IL-13 e IL-10. O bloqueio da via de SLAM associado à L. braziliensis e rIL-12 induziu aumento de IFN-&#947;, nos indivÃduos BP, e aumento de IL-13, nos indivÃduos AP. Os resultados deste trabalho sugerem que, na resposta in vitro de CMSP, sensibilizadas com L. braziliensis, a via de sinalizaÃÃo SLAM atua na modulaÃÃo da resposta Th1 em indivÃduos AP e induz uma condiÃÃo de imunossupressÃo temporÃria nos indivÃduos BP, nÃo descrita anteriormente na literatura. / Immune cells activation is modulated by balancing the signals triggered by a variety of cell surface receptors, including receptor activators, co-stimulating receptors and inhibitory receptors. Receptor-related signaling molecule in lymphocyte activation (SLAM) influences the immune cell activation. In this study we investigated the role of SLAM in immune response of cutaneous leishmaniasis caused by L. braziliensis, as well as if the response of individuals high (HP) or low (LP) IFN-&#947; producers is modulated by SLAM signaling pathway. Peripheral blood monocuclear cells (PBMC) isolated from 43 health individuals were cultured in vitro with anti-SLAM, rIFN-&#947;, rIL-12 and phytohemagglutinin in the presence or in the absence of L. braziliensis. It was found that L. braziliensis promoted a significantly reduced SLAM expression in T cells, after 120 h of cultured, possibly indicating activation of this pathway in the initial immune response. SLAM expression behaved differently in HP and LP groups. In LP group, L. braziliensis did not modify SLAM expression in T cells in early immune response. The effect of anti-SLAM on SLAM pathway reduced the expression of this protein in the early stages of the immune response of PBMC stimulated with L. braziliensis. After 120 h the effect of anti-SLAM did not alter CD3+SLAM+ expression in both groups. The proinflammatory cytokines, rIFN-&#947; and rIL-12, present in the microenvironment with L. braziliensis, reduced SLAM expression only in HP group after 6 h of culture and did not change this response after 120 h. Anti-SLAM at a concentration of 10 &#956;g/ml presented no effect on production of cytokines IFN-&#947; and IL-13 in both groups, but significantly increased IL-10 production in the HP group. Furthermore anti-SLAM associated with L. braziliensis and rIFN-&#947; simultaneously did not modify IFN-&#947;, IL-13 and IL-10 productions. Anti-SLAM associated with L. braziliensis and rIL-12 simultaneously induced an increase of IFN-&#947; in LP group, and increased IL-13 in HP group. These results suggest that in vitro immune response of PBMC exposed to L. braziliensis, the SLAM signaling pathway acts in modulating Th1 response in HP group and induces a condition of temporary immunosuppression in LP group, not previously described in literature.