Os linfócitos T CD4+ orquestram a resposta imune adaptativa, auxiliando os macrófagos, os linfócitos T CD8+ e os linfócitos B na resposta mais eficiente frente a um antígeno. As etapas que caracterizam uma resposta imune adaptativa são: apresentação do antígeno, ativação e diferenciação dos linfócitos T, expansão clonal e morte celular para retorno à homeostasia via AICD. Este tipo de morte ocorre via FAS/FASL. Tendo em vista que o mecanismo pelo qual a PGE2 inibe a expressão de fasl ainda não é conhecido, o presente trabalho tem como objetivo compreender o mecanismo molecular de atuação da PGE2 sobre os linfócitos T CD4+ na inibição gênica do FASL, tendo como hipótese o envolvimento do repressor transcricional ICER. Foi verificado que PGE2 10-8 M é capaz de proteger as DO11.10 da AICD e que, nesta concentração, ela induz a expressão de icer. Este repressor apresenta uma expressão transiente e observa-se seu aumento concomitantemente à inibição da expressão de fasl. Sendo assim, sugere-se a participação de ICER na via de inibição do fasl pela PGE2. / CD4+ T lymphocytes orchestrate the adaptive immune response, helping the macrophages, CD8+ T lymphocytes and B lymphocytes to reach an efficient antigen-specific immune response. The adaptive immune response is characterized by different phases: antigen, T lymphocyte activation and differentiation, clonal expansion and, finally, clonal cell death to return to homeostasis via AICD. This cell death occurs via FAS/FASL. Since the mechanism by which PGE2 inhibits fasl expression is not known, our aim is to understand the molecular mechanism responsible for PGE2 inhibition of fasl in CD4+ lymphocytes. Our hypothesis is that the transcriptional repressor ICER, which binds to CRE sites on gene promoters, is involved in this process. We verified that PGE2 10-8 M protects DO11.10 cells from AICD, and in that concentration, PGE2 increases icer expression. This repressor has a transient expression and we observed that its expression is increased in the same time that fasl expression is inhibited. Thus, we suggest the involvement of ICER in fasl inhibition pathway by PGE2.

Os linfócitos T CD4+ orquestram a resposta imune adaptativa, auxiliando os macrófagos, os linfócitos T CD8+ e os linfócitos B na resposta mais eficiente frente a um antígeno. As etapas que caracterizam uma resposta imune adaptativa são: apresentação do antígeno, ativação e diferenciação dos linfócitos T, expansão clonal e morte celular para retorno à homeostasia via AICD. Este tipo de morte ocorre via FAS/FASL. Tendo em vista que o mecanismo pelo qual a PGE2 inibe a expressão de fasl ainda não é conhecido, o presente trabalho tem como objetivo compreender o mecanismo molecular de atuação da PGE2 sobre os linfócitos T CD4+ na inibição gênica do FASL, tendo como hipótese o envolvimento do repressor transcricional ICER. Foi verificado que PGE2 10-8 M é capaz de proteger as DO11.10 da AICD e que, nesta concentração, ela induz a expressão de icer. Este repressor apresenta uma expressão transiente e observa-se seu aumento concomitantemente à inibição da expressão de fasl. Sendo assim, sugere-se a participação de ICER na via de inibição do fasl pela PGE2. / CD4+ T lymphocytes orchestrate the adaptive immune response, helping the macrophages, CD8+ T lymphocytes and B lymphocytes to reach an efficient antigen-specific immune response. The adaptive immune response is characterized by different phases: antigen, T lymphocyte activation and differentiation, clonal expansion and, finally, clonal cell death to return to homeostasis via AICD. This cell death occurs via FAS/FASL. Since the mechanism by which PGE2 inhibits fasl expression is not known, our aim is to understand the molecular mechanism responsible for PGE2 inhibition of fasl in CD4+ lymphocytes. Our hypothesis is that the transcriptional repressor ICER, which binds to CRE sites on gene promoters, is involved in this process. We verified that PGE2 10-8 M protects DO11.10 cells from AICD, and in that concentration, PGE2 increases icer expression. This repressor has a transient expression and we observed that its expression is increased in the same time that fasl expression is inhibited. Thus, we suggest the involvement of ICER in fasl inhibition pathway by PGE2.

Após a resposta imune, a expansão dos linfócitos T CD4 é seguida de uma fase de retração chamada Morte Celular induzida por Ativação (AICD), para que a homeostasia seja reestabelecida. Nosso grupo demonstrou que DCs estimuladas com LPS produzem PGE2 que inibe a expressão de FASL e bloqueia a AICD dos linfócitos T CD4. Nossa hipótese é que a apresentação de antígenos em contexto de infecção tenha um impacto na expressão de FASL e na sobrevivência das células T CD4, de maneira dependente de TLRPGE2. Para comprovar nossa hipótese nós estudamos a apresentação de OVA in vitro e in vivo. Observamos que a adição de LPS durante a apresentação de OVA aumenta a ativação e proliferação das células T CD4 específicas. O pré-tratamento dos camundongos com Indometacina, um inibidor da enzima COX, reduz a frequência das células específicas através do aumento na expressão de FASL e da apoptose, mas sem interferir com a proliferação. Nós sugerimos que a PGE2 produzida em resposta ao LPS regule a sobrevivência dos linfócitos T CD4 durante a persistência do estímulo antigênico. / After immune response, expansion of antigen-specific CD4 T cells is followed by a contraction phase due to Activation-Induced Cell Death (AICD) to reestablish homeostasis. Our group demonstrated that LPS stimulated-DCs produce PGE2 that protects CD4 T cells from AICD by preventing TCR/CD3-mediated FASL upregulation. Our hypothesis is that antigen presentation in the context of infection impacts on FASL expression and survival of CD4 T cells, dependently on TLR-mediated PGE2 release. To approach our hypothesis we studied OVA presentation in vitro and in vivo. We observed that the addition of LPS during OVA presentation increased specific CD4+ T cells activation and proliferation. Pretreatment of mice with indomethacin, an inhibitor of COX enzyme, reduces the frequency of specific T cells by increasing FASL expression and apoptosis, but did not interfere with proliferation. We suggest that PGE2 produced in response to LPS regulates the survival of CD4 T lymphocytes during persistent antigen stimulation.

Linfócitos T CD4+ (LTCD4) sofrem morte pelo reestímulo do TCR em um processo chamado de AICD (activation-induced cell death) no fim de uma resposta imune. Resultados prévios de nosso grupo de pesquisa mostraram que melatonina foi capaz de inibir o processo de AICD em LTCD4 em experimentos in vitro. Portanto, o objetivo deste trabalho é verificar se a melatonina é capaz de agir como estimulador, aumentando a resposta imune mediada pelos LTCD4 in vivo. Nós observamos que 3 e 9mg/Kg de melatonina aumentaram a resposta de DTH (Delayed-type Hypersensitivity), de forma diretamente proporcional à dose utilizada. O tratamento com melatonina estimulou um aumento da proliferação e do numero absoluto de LTCD4 específicos de antígeno. Em experimentos de diferenciação linfocitária in vitro, nós observamos que o tratamento com melatonina estimulou a produção de LTCD4 do perfil Th1 e Th2, no entanto inibiu a produção de linfócitos Th17. Em conclusão, nossos resultados sugerem um efeito estimulador da melatonina sobre a função de linfócitos T CD4+. / CD4+ T lymphocytes (LTCD4+) suffer cell death by a process known as activation-induced cell death (AICD) at the end of immune response. Previous results from our group showed that melatonin can inhibits AICD process in LTCD4 at in vitro experiments. Therefore, the aim of this work is verify if a melatonin can act as immune stimulator increasing a LTCD4-mediated immune response in vivo. We showed that 3 and 9 mg/Kg of exogenous melatonin added during immunization resulted in potentiation dose-dependent of Delayed-type hypersensitivity (DTH) response. The treatment with melatonin increased the absolute number LTCD4 antigen-specific, probably by increment of its proliferation. In experiment of T cell differentiation, we observed that the treatment with melatonin stimulated LTCD4 production of Th1 and Th2 profile however blocked the Th17 lymphocytes production. In conclusion, our results support the idea about a regulator role of melatonin on LTCD4 lymphocytes function for development of an immune response.

Linfócitos T CD4+ (LTCD4) sofrem morte pelo reestímulo do TCR em um processo chamado de AICD (activation-induced cell death) no fim de uma resposta imune. Resultados prévios de nosso grupo de pesquisa mostraram que melatonina foi capaz de inibir o processo de AICD em LTCD4 em experimentos in vitro. Portanto, o objetivo deste trabalho é verificar se a melatonina é capaz de agir como estimulador, aumentando a resposta imune mediada pelos LTCD4 in vivo. Nós observamos que 3 e 9mg/Kg de melatonina aumentaram a resposta de DTH (Delayed-type Hypersensitivity), de forma diretamente proporcional à dose utilizada. O tratamento com melatonina estimulou um aumento da proliferação e do numero absoluto de LTCD4 específicos de antígeno. Em experimentos de diferenciação linfocitária in vitro, nós observamos que o tratamento com melatonina estimulou a produção de LTCD4 do perfil Th1 e Th2, no entanto inibiu a produção de linfócitos Th17. Em conclusão, nossos resultados sugerem um efeito estimulador da melatonina sobre a função de linfócitos T CD4+. / CD4+ T lymphocytes (LTCD4+) suffer cell death by a process known as activation-induced cell death (AICD) at the end of immune response. Previous results from our group showed that melatonin can inhibits AICD process in LTCD4 at in vitro experiments. Therefore, the aim of this work is verify if a melatonin can act as immune stimulator increasing a LTCD4-mediated immune response in vivo. We showed that 3 and 9 mg/Kg of exogenous melatonin added during immunization resulted in potentiation dose-dependent of Delayed-type hypersensitivity (DTH) response. The treatment with melatonin increased the absolute number LTCD4 antigen-specific, probably by increment of its proliferation. In experiment of T cell differentiation, we observed that the treatment with melatonin stimulated LTCD4 production of Th1 and Th2 profile however blocked the Th17 lymphocytes production. In conclusion, our results support the idea about a regulator role of melatonin on LTCD4 lymphocytes function for development of an immune response.

Após a resposta imune, a expansão dos linfócitos T CD4 é seguida de uma fase de retração chamada Morte Celular induzida por Ativação (AICD), para que a homeostasia seja reestabelecida. Nosso grupo demonstrou que DCs estimuladas com LPS produzem PGE2 que inibe a expressão de FASL e bloqueia a AICD dos linfócitos T CD4. Nossa hipótese é que a apresentação de antígenos em contexto de infecção tenha um impacto na expressão de FASL e na sobrevivência das células T CD4, de maneira dependente de TLRPGE2. Para comprovar nossa hipótese nós estudamos a apresentação de OVA in vitro e in vivo. Observamos que a adição de LPS durante a apresentação de OVA aumenta a ativação e proliferação das células T CD4 específicas. O pré-tratamento dos camundongos com Indometacina, um inibidor da enzima COX, reduz a frequência das células específicas através do aumento na expressão de FASL e da apoptose, mas sem interferir com a proliferação. Nós sugerimos que a PGE2 produzida em resposta ao LPS regule a sobrevivência dos linfócitos T CD4 durante a persistência do estímulo antigênico. / After immune response, expansion of antigen-specific CD4 T cells is followed by a contraction phase due to Activation-Induced Cell Death (AICD) to reestablish homeostasis. Our group demonstrated that LPS stimulated-DCs produce PGE2 that protects CD4 T cells from AICD by preventing TCR/CD3-mediated FASL upregulation. Our hypothesis is that antigen presentation in the context of infection impacts on FASL expression and survival of CD4 T cells, dependently on TLR-mediated PGE2 release. To approach our hypothesis we studied OVA presentation in vitro and in vivo. We observed that the addition of LPS during OVA presentation increased specific CD4+ T cells activation and proliferation. Pretreatment of mice with indomethacin, an inhibitor of COX enzyme, reduces the frequency of specific T cells by increasing FASL expression and apoptosis, but did not interfere with proliferation. We suggest that PGE2 produced in response to LPS regulates the survival of CD4 T lymphocytes during persistent antigen stimulation.

Seventeen new dithiophenyl- and napthodithiophenyl- fused porphyrins were synthesized; from these an additional 7 porphyrin oligomers were also synthesized. Additionally freebase 2,7-dimethoxytriphenylene fused porphyrin was also synthesized from a freebase precursor. Aromatic indices NICS and AICD were used to evaluate these new molecules.

Un des défis majeurs de l’immunologie antitumorale repose sur l’induction efficace et prolongée de laphase effectrice de la réponse immune antitumorale. Une meilleure compréhension des mécanismesimpliqués dans la potentialisation de l’activité antitumorale des effecteurs immunitaires, en particulier lesCTL infiltrant la tumeur représente donc un enjeu considérable dans le développement de nouvellesapproches d’immunothérapie visant à induire une réponse immunitaire spécifique efficace contre latumeur. Dans ce contexte, nous nous sommes particulièrement intéressés à étudier le rôle de CD5 dans lecontrôle de la progression tumorale, en particulier dans la potentialisation de l’activité T cytotoxique desCTL infiltrant le mélanome B16 in vivo. Nos résultats ont montré un ralentissement significatif de lacroissance tumorale chez des souris déficientes pour l’expression de CD5 comparées à leurs équivalentessauvages. Le contrôle de la progression de la tumeur chez les souris CD5-/- ne semble pas corréler avec unrecrutement plus important de lymphocytes T, mais avec une efficacité accrue de leur réactivité vis-à-visdu mélanome B16. Nous avons montré aussi que cette réponse est transitoire et qu’un échappementtumoral au système immunitaire ait lieu à un stade plus tardif de la progression de la tumeur. Cetéchappement tumoral semble être associé à une augmentation de la mort par AICD des TIL CD8+/CD5-par rapport aux TIL CD8+/CD5+ et ce par induction de FasL à la surface des TIL. La modulation de la voieFas/FasL in vivo avec un adénovirus Fas-Fc protège les lymphocytes T CD8+/CD5- infiltrant la tumeur dela mort par apoptose et empêche ainsi l’échappement tumoral. De plus, l’analyse du répertoirelymphocytaire T spécifique du mélanome B16 dans les souris CD5-/- suggère que le contrôle de laprogression de la tumeur serait lié à une meilleure prolifération de lymphocytes T CD5-/- spécifiques insitu. Nos résultats montrent aussi que l’immunisation des souris CD5-/- en utilisant des Ag tumorauxassociés au mélanome B16 contribue à la potentialisation de la réponse immunitaire antitumorale.L’ensemble de nos résultats soulignent un intérêt particulier du ciblage de CD5 pour améliorer lesapproches d’immunothérapie antitumorale actuelles. / A major challenge in tumor immunology is based on effective and prolonged induction of the effectorphase of antitumor immune response. A better understanding of the mechanisms involved in potentiatingthe antitumor activity of immune effectors, particularly the CTL infiltrating the tumor represents aconsiderable challenge in developing new approaches to immunotherapy. In this context we areparticularly interested in studying the role of CD5 in the control of tumor progression, particularly inpotentiating the cytotoxic activity of CTLs infiltrating B16 melanoma. Our results showed a significantdelay in tumor growth in CD5-/- mice as compared with wild type mice. The control of tumor growth inCD5-/- mice does not seem to correlate with a higher recruitment of T cells, but with increased cytotoxicityof infiltrating T cells against B16 cells. We have also shown that this response is transient and that thetumor escape from immune system takes place at a later stage of tumor progression. This tumor escapeappears to be associated with increased death by AICD of TIL CD8+ from CD5-/- mice as compared withTIL CD8+ from wild type mice wich correlated with the induction of FasL on the surface of TIL. In vivomodulation of Fas/FasL with an adenovirus AdFas-Fc protects tumor infiltrating T CD8+/CD5- fromapoptosis and thereby prevents the tumor escape. In addition, analysis of specific T lymphocyte repertoirein CD5-/- mice suggests that the control of tumor progression could be linked to a greater in situproliferation of specific CD5- T lymphocytes. Our results also show that immunization of CD5-/- miceusing different melanoma associated antigens contributes to the potentiation of antitumor immuneresponse. All these results highlight a particular interest in targeting of CD5 to improve currentapproaches to tumor immunotherapy.

Hybrid striped bass (Morone chrysops x M. saxatilis) aquaculture is a major commercial enterprise in the United States and internationally. Efforts to decrease diet costs and limit dependence on fishmeal, have led to the development of plant-based diets as an alternative aquafeed. Due to limiting concentrations of amino acids such as methionine, cystine, and taurine in plant meals such as soybean meal, supplementation of these plant-based diets with methionine or other sulfur amino acid compounds is typically required. Therefore, the current study was conducted to evaluate different amino acid supplements in soybean-meal-based diets for hybrid striped bass for possible refinement of diets and reduction of production costs. One feeding trial evaluated methionine hydroxy analog (MHA) and Mintrex® which is MHA containing chelated zinc relative to L-methionine. The second trial evaluated the effects of supplemental taurine or arginine on fish performance and potential health benefits. In the first feeding trial, a basal soybean-meal-based diet (56% soybean meal and 15% fishmeal) marginally deficient in total sulfur amino acids (TSSA) (1.10% methionine and cystine) was supplemented with either L-methionine, Mintrex® or MHA calcium salt and fed to triplicate groups of juvenile hybrid striped bass for 10 weeks. The different methionine supplements provided similar weight gain, feed efficiency ratio (FER) and protein efficiency ratio (PER) values that tended to be greater than observed in fish fed the basal diet. Mintrex® supplementation provided much higher plasma zinc concentrations compared to fish fed the other methionine supplements. In the second feeding trial, soybean-meal based diets which satisfied the requirement for TSAA were supplemented with either taurine or arginine at 1.5% of dry weight. Supplemental taurine or arginine did not provide any improvements in weight gain, FER, PER or survival compared to the basal diet. Thus, taurine or arginine supplementation of soybean-meal-based diets does not appear warranted. However, sulfur amino acid supplementation of plant-based diets is critical, and Mintrex® appears to be an effective supplement to meet the methionine and zinc needs of hybrid striped bass.

Dispositional optimism, as a stable outcome expectancy, has been shown to predict health outcomes in several contexts. Research has demonstrated that health-impaired subjects with optimistic outlooks fared better than those with a pessimistic outlook. Choice of coping strategies has been theorized as the mediating factor through which optimism operates. However, the construct of dispositional optimism has been challenged as a polar opposite of neuroticism, thus contending that optimism is not an independent notion. The present study was designed to evaluate further the theoretical underpinnings of dispositional optimism theory. Subjects were selected from a population of cardiac patients who received an automatic implantable cardioverter defibrillator (AICD). This device, designed to save the patient from sudden cardiac death, dispenses an electric shock to the heart should it exhibit sustained ventricular tachycardia or fibrillation. This research project examined the relationship of dispositional optimism, coping, and neuroticism to psychological distress, life satisfaction, health perception, and frequency of prior AICD discharges. Intact data from 50 of the 60 participants were examined in multiple regression analyses. The results of the analyses were diverse. Principal findings were (a) general psychological distress was predicted solely by neuroticism but optimism predicted the majority of unique variance in the "style" with which subjects approach the assessment of distress; (b) optimism was subsumed under neuroticism in predicting health perception; (c) avoidance coping interacted with optimism in predicting a significant amount of unique variance over and above neuroticism in the number of AICD discharges experienced by the patients. In this latter finding, pessimistic patients who did not use avoidance coping received a greater number of discharges. Thus, optimism and neuroticism were not parallel constructs in all dependent variables. Also, the optimism/avoidance coping interaction in predicting an actual medical outcome was unprecedented. Limitations and directions for future research were discussed.