CD40 is a TNF receptor superfamily (TNFRSF) member central to the development of many aspects of the adaptive immune response. CD40 signaling promotes adaptive immunity in part by inducing the expression of cytokines, chemokines, and various adhesion and co-stimulatory molecules. The family of cytoplasmic adapter proteins, the TNFR-associated factors (TRAFs), serve as major mediators of TNFRSF pathways. CD40 regulates itself in part via the signaling induced degradation of TRAF2 and TRAF3. However, the effect of CD40-induced TRAF degradation on other TRAF dependent pathways is unknown. Here I provide evidence that CD40-mediated degradation of TRAFs 2 and 3 also influences the responsiveness of immune cells to CD40-independent, TRAF2- and 3-dependent pathways. LMP1 is a functional mimic of CD40, but signals to B lymphocytes in an amplified and sustained manner. LMP1 contributes to the development of B cell lymphoma in immunosuppressed patients, and may exacerbate flares of certain autoimmune diseases. The cytoplasmic (CY) domain of LMP1 binds TRAF2 with lower avidity than the CY domain of CD40, and TRAF2 is needed for CD40-mediated degradation of TRAFs 2 and 3. LMP1 doesn't induce TRAF degradation, and employs TRAF3 as a positive mediator of cell signaling, whereas CD40 signals are inhibited by TRAF3. Here, I tested the hypothesis that relative affinity for TRAF2, and/or distinct sequence differences in the TRAF2/3 binding sites of CD40 vs. LMP1, controls the disparate ways in which CD40 and LMP1 use TRAFs 2 and 3. The results revealed that TRAF binding affinity and TRAF binding site sequence dictate a distinct subset of CD40 vs. LMP1 signaling properties. The E3 ubiquitin ligases, cIAP1 and cIAP2, have been reported to play a crucial role in CD40 signaling. Because LMP1 is a mimic of CD40 signals, I hypothesized that LMP1 requires the cIAPs for signaling. To elucidate the role of the cIAPs in CD40 and LMP1 signaling, I specifically depleted the cIAPs and found that the cIAPs are differentially utilized in CD40 and LMP1 signaling. I also sought to further the understanding of the molecular underpinnings of how CD40, but not LMP1 signaling induces TRAF2 and TRAF3 degradation upon signaling. To do this, I investigated the ability of various CD40 and LMP1 mutants to induce TRAF degradation in distinct TRAF or cIAP deficient models. I found that neither a high TRAF2 binding potential nor the presence of the cIAP molecules are required for this process. Thus, this work reveals important insights into the molecular mechanisms of and role of CD40-mediated TRAF degradation in the immune system.

A dengue é uma doença infecciosa aguda causada pelo vírus DEN do gênero Flavivirus e é transmitida pela picada de um mosquito vetor, principalmente o Aedes aegypti. Existem quatro sorotipos do vírus da dengue (DEN-1, DEN-2, DEN-3 e DEN-4) e sua incidência tem aumentado dramaticamente nos últimos 50 anos, inclusive no Brasil. O objetivo deste trabalho é caracterizar subpopulações de linfócitos T, principalmente linfócitos T CD8+, provenientes de pacientes infectados quanto a sua capacidade proliferativa, seu estado de ativação e memória celular. Os pacientes foram recrutados no Hospital Ana Costa de Santos, SP, no ano de 2010, após assinarem o Termo de Consentimento Livre e Esclarecido. O diagnóstico de dengue foi realizado utilizando o teste rápido Dengue Duo e os parâmetros imunológicos foram analisados no citômetro de fluxo. Foi coletado sangue periférico para criopreservação de células mononucleares e separação de soro para detecção da carga viral. Pacientes com dengue apresentaram maior proliferação de linfócitos T CD8+ quando comparados com indivíduos saudáveis. Foi ainda observado que tal proliferação celular foi evidente nos dias cinco e seis de sintomas. Quando marcadores de ativação celular foram analisados por citometria de fluxo, observou-se um aumento de linfócitos T CD8+ expressando CD38 e HLA-DR nos pacientes, quando comparados com indivíduos saudáveis. Da mesma forma, a ativação celular também aumentou com o passar dos dias de sintomas com destaque para o quinto e sexto dia. Este aumento na ativação das células juntamente com os dias de sintomas, foi igualmente observado em várias subpopulações de células T de memória Além disso, foi observada uma correlação negativa entre o número absoluto de linfócitos T CD8+ e a carga viral. Juntos, os resultados desse estudo sugerem que a infecção por DEN leva a um aumento da ativação de células T CD8+ / Dengue is an acute disease caused by DEN, a Flavivirus transmitted by a mosquito vector, primarily Aedes aegypti. There are four serotypes of dengue viruses (DEN-1, DEN-2, DEN-3 and DEN-4) and their incidences have increased dramatically over the past 50 years, including in Brazil. The goal of this study is to characterize subpopulations of T lymphocytes, mainly CD8+ T cells, from infected patients. Status of cell activation, and memory cell profiles were assessed. Patients were recruited at Hospital Ana Costa, Santos-SP, Brazil, in 2010, after having signed an informed consent form. The serologic diagnosis of dengue was carryied out using a rapid test and immunological parameters were analyzed in flow cytometer. Peripheral blood was collected for cryopreservation of mononuclear cells and separation of serum for viral load testing. Dengue patients showed higher proliferation of CD8+ T cells compared to healthy subjects. Cell proliferation was more evident in the fifth and sixth days of symptoms. We observed increased frequency of CD8+ T cells expressing activation markers CD38 and HLA-DR in patients, when compared to healthy subjects. Similarly, T cell activation also increased along with the passing days of symptoms hitting on the fifth and the sixth days. Such augment in cellular activation along with the days of symptoms was equally observed in the several memory T cell compartments. Furthermore, we observed a negative correlation between the absolute number of CD8+ T lymphocytes and viral load. Together, the results of this study suggest that dengue virus infection leads to an increased activation of CD8+ T cells

A dengue é uma doença infecciosa aguda causada pelo vírus DEN do gênero Flavivirus e é transmitida pela picada de um mosquito vetor, principalmente o Aedes aegypti. Existem quatro sorotipos do vírus da dengue (DEN-1, DEN-2, DEN-3 e DEN-4) e sua incidência tem aumentado dramaticamente nos últimos 50 anos, inclusive no Brasil. O objetivo deste trabalho é caracterizar subpopulações de linfócitos T, principalmente linfócitos T CD8+, provenientes de pacientes infectados quanto a sua capacidade proliferativa, seu estado de ativação e memória celular. Os pacientes foram recrutados no Hospital Ana Costa de Santos, SP, no ano de 2010, após assinarem o Termo de Consentimento Livre e Esclarecido. O diagnóstico de dengue foi realizado utilizando o teste rápido Dengue Duo e os parâmetros imunológicos foram analisados no citômetro de fluxo. Foi coletado sangue periférico para criopreservação de células mononucleares e separação de soro para detecção da carga viral. Pacientes com dengue apresentaram maior proliferação de linfócitos T CD8+ quando comparados com indivíduos saudáveis. Foi ainda observado que tal proliferação celular foi evidente nos dias cinco e seis de sintomas. Quando marcadores de ativação celular foram analisados por citometria de fluxo, observou-se um aumento de linfócitos T CD8+ expressando CD38 e HLA-DR nos pacientes, quando comparados com indivíduos saudáveis. Da mesma forma, a ativação celular também aumentou com o passar dos dias de sintomas com destaque para o quinto e sexto dia. Este aumento na ativação das células juntamente com os dias de sintomas, foi igualmente observado em várias subpopulações de células T de memória Além disso, foi observada uma correlação negativa entre o número absoluto de linfócitos T CD8+ e a carga viral. Juntos, os resultados desse estudo sugerem que a infecção por DEN leva a um aumento da ativação de células T CD8+ / Dengue is an acute disease caused by DEN, a Flavivirus transmitted by a mosquito vector, primarily Aedes aegypti. There are four serotypes of dengue viruses (DEN-1, DEN-2, DEN-3 and DEN-4) and their incidences have increased dramatically over the past 50 years, including in Brazil. The goal of this study is to characterize subpopulations of T lymphocytes, mainly CD8+ T cells, from infected patients. Status of cell activation, and memory cell profiles were assessed. Patients were recruited at Hospital Ana Costa, Santos-SP, Brazil, in 2010, after having signed an informed consent form. The serologic diagnosis of dengue was carryied out using a rapid test and immunological parameters were analyzed in flow cytometer. Peripheral blood was collected for cryopreservation of mononuclear cells and separation of serum for viral load testing. Dengue patients showed higher proliferation of CD8+ T cells compared to healthy subjects. Cell proliferation was more evident in the fifth and sixth days of symptoms. We observed increased frequency of CD8+ T cells expressing activation markers CD38 and HLA-DR in patients, when compared to healthy subjects. Similarly, T cell activation also increased along with the passing days of symptoms hitting on the fifth and the sixth days. Such augment in cellular activation along with the days of symptoms was equally observed in the several memory T cell compartments. Furthermore, we observed a negative correlation between the absolute number of CD8+ T lymphocytes and viral load. Together, the results of this study suggest that dengue virus infection leads to an increased activation of CD8+ T cells

Made available in DSpace on 2014-12-17T14:03:36Z (GMT). No. of bitstreams: 1 JoaoFRN_DISSERT.pdf: 3516278 bytes, checksum: 9fe0338a2547517c2f45d91b7860116c (MD5) Previous issue date: 2010-12-03 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Visceral leishmaniasis (VL) in Brazil is a disease caused by Leishmania infantum chagasi (L.i.chagasi). The clinical evolution post-infection depends on the vertebrate host immune response, which is genetically mediated. This study aimed to evaluate the immune response of individuals living in endemic area for VL in the state of the Rio Grande do Norte, considering individuals with VL under treatment (n = 9), recovered VL <1 year post treatment (n = 10), > 10 years posttreatment (n = 9), uninfected individuals living in endemic areas (n = 7), individuals that lost DTH response (n=6) and asymptomatic individuals for VL (n=9). Peripheral blood cells were evaluated in the presence and absence of soluble Leishmania antigens (SLA) and ex vivo, to determine activation, presence of regulatory cells and memory cells. The Leishmania parasitemia and anti-Leishmania antibodies were determined respectively by qPCR and ELISA. Cells from individuals with VL under treatment showed less cell activation after stimulation with SLA for the markers CD4/CD69, CD8/CD69 and CD8/CD25 compared with VL post treatment treatment (p <0.001). Apparently uninfected individuals have a higher cell activation than symptomatic VL (p <0.001), with the exception of CD8/CD25 marker (p = 0.6662). On the other hand, in the ex-vivo group, significant differences were observed for CD4/CD69, CD8/CD69 and CD8/CD25 between the 4 groups due to increased cell activation present in cells of individuals symptomatic LV (p <0.001). VL cells under treatment, ex vivo, have a lower percentage of memory cells (CD4/CD45RO and CD8/CD45RO) than individuals VL post-treatment or control group (p = <0.01). Likewise, individuals with symptomatic VL have fewer regulatory cells when stimulated by SLA [CD4/CD25 (p = 0.0022) and CD4/FOXP3 (p = 0.0016)] and in the ex-vivo group (p = 0.0017). Finally, DNA isolated from recovered VL contained Leishmania DNA, supporting the hypothesis of non-sterile clinical cure for Leishmania infection. Recovered VL, even 10 years after treatment have high levels of memory cells, which may be due to the presence of stimulation, either by reexposure to Leishmania or non-sterile cure / A Leishmaniose visceral (LV) nas Am?ricas ? uma doen?a causada pela esp?cie Leishmania infantum chagasi (L.i.chagasi). A forma cl?nica evolutiva p?s-infec??o depende da resposta imune do hospedeiro vertebrado, que ? geneticamente mediada. Este estudo teve como objetivo avaliar a resposta imune de indiv?duos residentes em ?rea end?mica para LV no estado do Rio Grande do Norte, considerando indiv?duos com LV em tratamento (n=9), indiv?duos curados de LV < 1 ano (n=10) e > 10 anos p?s-tratamento (n=9), indiv?duos residentes em ?reas end?micas (n=7) aparentemente n?o infectados, indiv?duos que perderam a resposta DTH (n=6) e indiv?duos assintom?ticos para LV (n=9). C?lulas de sangue perif?rico foram avaliadas em presen?a e na aus?ncia de ant?genos sol?veis de Leishmania (SLA) e ex-vivo, para determina??o da ativa??o, da presen?a de c?lulas regulat?rias e de c?lulas de mem?ria. A parasitemia e anticorpo anti-Leishmania foram determinadas, respectivamente, por qPCR e ELISA. C?lulas oriundas de indiv?duos com LV em tratamento apresentaram menor ativa??o celular p?s-est?mulo com SLA para os marcadores CD4/CD69, CD8/CD69 e para CD8/CD25 quando comparado com LV p?s-tratamento (p<0,001). Indiv?duos aparentemente n?o infectados apresentam maior ativa??o celular que LV sintom?tico (p<0.001), com exce??o do marcador CD8/CD25 (p=0,6662). Por outro lado, na condi??o ex-vivo, diferen?as significativas foram observadas para CD4/CD69, CD8/CD69 e CD8/CD25 devido a uma maior ativa??o celular presente em c?lulas de indiv?duos LV sintom?ticos (p<0,001). Indiv?duos LV sintom?ticos, ex vivo, apresentam um menor percentual de c?lulas de mem?ria (CD4/CD45RO CD8/CD45RO) do que indiv?duos com LV p?stratamento ou controles (p=<0.01). Da mesma forma, indiv?duos com LV sintom?ticos apresentam uma menor quantidade de c?lulas regulat?rias quando estimuladas por SLA [CD4/CD25 (p= 0,0022) e CD4/FOXP3 (p= 0,0016)] e na condi??o ex-vivo (p=0.0017). Finalmente, pacientes com LV clinicamente recuperados permaneceram com parasitemia, determinado por qPCR, dando suporte ? hip?tese de cura cl?nica n?o est?ril para infec??o por Leishmania. Pacientes com LV recuperado, mesmo 10 anos p?s-tratamento mant?m n?veis elevados de c?lulas de mem?ria, que pode ser devido ? presen?a de ant?genos de Leishmania, seja devido ? re-exposi??o ? Leishmania ou por uma prov?vel cura n?o est?ril

La cytométrie de masse CMM) a révolutionné l'étude de la diversité cellulaire et phénotypique, en augmentant de manière significative le nombre de marqueurs pouvant être analysés simultanément (41 à ce jour). En permettant de définir précisément l'état des populations de lymphocytes, notamment en ce qui concerne leur différenciation, activation et leur entrée dans le cycle cellulaire, la CMM a mis au jour de petits sous-ensembles jusqu'ici inconnus. Dans cette étude, la CMM a été utilisée pour tenter de mieux caractériser les réservoirs du VIH. Avec l'introduction de la thérapie antirétrovirale combinée (ART) en 1996, l'infection par le VIH est passée d'un destin fatal à une maladie chronique gérable avec une durée de vie normale grâce à une réduction de la réplication virale active (la quantité de virus est en deçà des limites de détection optimales). Cependant, si le traitement est interrompu, la charge virale chez le patient augmente à nouveau du fait des réservoirs de provirus viables localisés dans des populations de cellules à longue durée de vie et qui ne peuvent pas être éliminées par les traitements actuels. Ces cellules infectées réservoirs constituent un obstacle majeur à l'éradication du VIH. Le réservoir le mieux caractérisé est celui des lymphocytes T CD4+ et est principalement hébergé dans les TCM, les TTM, les TSCM et les Tfh. Une première étude nous a permis d’évaluer les stades du cycle cellulaire en association à des marqueurs de différenciation, d'activation et d'épuisement, pour aboutir à une évaluation poussée de l'état de quiescence des lymphocytes T CD4 susceptibles d’abriter les réservoirs latents de VIH. Cette large analyse multiplexe démontre que certains sous-ensembles des LTCD4+CD25-HLA-DR- classiquement considérés "au repos"- contiennent en fait des quantités notables de cellules en cycle ou exprimant des récepteurs inhibiteurs, ouvrant de nouvelles voies pour une redéfinition des cellules T CD4 quiescentes du sang périphérique. Une deuxième étude avait pour but de définir les populations de LT CD4 produisant du VIH in vivo. Nous avons développé une analyse multiparamétrique sur des cellules de patients VIH+ sous ART et en phase d’interruption thérapeutique (ATI). Cette étude met en évidence que les cellules CD3+CD4+CD32high expriment un fort taux de marqueurs d’activation et reçoivent d’importants signaux d’activation via des cytokines, à l'inverse des cellules CD32a-. D'autre part, l'analyse des LTCD4+ producteurs de VIH (exprimant la protéine de capside p24), nous a permis de détecter un très faible nombre de cellules positives p24+ (inférieur à 0,004% en phase d’ATI mais aucun avant). Le phénotype des cellules productrices a ensuite été mis en évidence. Il s’agit de lymphocytes T n’exprimant pas de CD8, enrichis d’un facteur 4 en cellules TSCM, et d'un facteur 2 en TFH. Ces populations sont très enrichies en cellules activées co-exprimant 3 marqueurs d’activation (augmentés d’un facteur 20) et sont en cycle (Ki67+) et/ou sur-expriment des molécules de contrôle immunitaire (ICP) avec un enrichissement d’un facteur 500. Ceci nous permet de détecter des cellules productrices avec des fréquences beaucoup plus élevées dans ces populations TCD3+CD8- en cycle à hauteur de 0,08%, et en phase G2 (2,46%), mais également dans les cellules présentant une poly-expression des 4 immune-checkpoints (2,27%). L’avènement de la cytométrie de masse a augmenté de façon exponentielle les informations que nous pouvions obtenir sur une cellule. Grâce à cet outil, l’identification du cycle cellulaire, en corrélation avec différents marqueurs phénotypiques, permet d’explorer des informations jusque-là inaccessibles, entre autre l’analyse des réservoirs latents et productif du VIH. Ce travail permet ainsi de caractériser le plus précisément possible ces cellules productrices de VIH, mais aussi les cellules latentes, et potentiellement réservoirs du virus. / Mass cytometry (CMM) has revolutionized the study of cell and phenotypic diversity, significantly increasing the number of markers that can be analyzed simultaneously (41 to date). By making it possible to precisely define the state of the lymphocyte populations, particularly regarding their differentiation, activation and entry into the cell cycle, the CMM has revealed small subsets so far unknown. In this study, the CMM was used to try to better characterize the HIV’s reservoirs. With the introduction in 1996 of Combined Antiretroviral Therapy (ART), HIV infection has shifted from a fatal destiny to a manageable chronic disease with a normal life span through a reduction in active viral replication (the amount of virus is below optimal detection limits). However, if treatment is interrupted, the viral load increases again in the patient due to viable provirus reservoirs located in long-lived cell populations that cannot be eliminated by current treatments. These reservoirs constitute a major obstacle to the eradication of HIV. The best characterized reservoir is that of CD4+ T cells and is mainly hosted in TCM, TTM, TSCM and Tfh. A first study allowed us to evaluate the stages of the cell cycle in association with markers of differentiation, activation and exhaustion, leading to a thorough assessment of the quiescent state of CD4 T cells likely to harbour latent reservoirs of HIV. This broad multiplex analysis demonstrates that some subsets of LTCD4+CD25-HLA-DR- classically considered "at rest" – do actually contain significant amounts of cells in cycling or expressing inhibitory receptors, opening new pathways for redefining CD4 T quiescent cells from peripheral blood. A second study aimed to define CD4+ T Cells populations producing HIV in vivo. We have developed a multiparametric analysis on cells of HIV+ patients under ART and in therapeutic interruption phase (ATI). This study shows that CD3+CD4+CD32high cells express a high level of activation markers and receive important activation signals via cytokines, unlike CD32a- cells. On the other hand, the analysis of HIV-producing LTCD4+ (expressing the p24 capsid protein), allowed us to detect a very small number of p24+ positive cells (less than 0.004% in ATI phase but none before). The phenotype of the producing cells was then highlighted. These are T lymphocytes that do not express CD8, enriched with a factor 4 in TSCM cells, and a factor 2 in TFH. These populations are highly enriched in activated cells co-expressing 3 activation markers (increased by a factor of 20) and are in cycle (Ki67+) and/or over-express immune control molecules (ICPs) with an enrichment of a factor of 500. This allows us to detect producing cells with much higher frequencies in these TCD3+CD8- populations in cycles up to 0.08%, and in G2 phase (2.46%), but also in cells with poly-expression of 4 immune-checkpoints (2.27%). The advent of mass cytometry has exponentially increased the information we could get on a cell. Thanks to this tool, cell cycle identification, in correlation with different phenotypic markers, makes possible the exploration of previously inaccessible information, including the analysis of latent and productive reservoirs of HIV. This work enables us to characterize as precisely as possible these HIV-producing cells, but also the latent cells, and potentially reservoirs of the virus.

A profilaxia pré-exposição (PrEP) ao HIV se consolidou como uma importante estratégia de combate ao avanço da epidemia. Ainda assim, a incidência de casos da infecção vem aumentando na população jovem, assim como a de outras infecções sexualmente transmissíveis (ISTs), que atuam como importante fator de risco para transmissão do HIV-1. Entre as infecções mais frequentemente diagnosticadas estão Chlamydia trachomatis (CT) e Neisseria gonorrhoeae (NG). A presença de lesões na mucosa genital e anal são fatores de risco estabelecidos para a transmissão do HIV-1, porém o impacto das infecções assintomáticas ainda é pouco conhecido. Dados recentes mostram que a ativação sistêmica de linfócitos T é um fator de risco para a aquisição da infecção pelo HIV-1. Nesse estudo, estudamos a ativação de linfócitos T na presença de infecção anorretal assintomática por CT e/ou NG. Células mononucleares do sangue periférico de voluntários do PrEP Brasil, um estudo clínico demonstrativo de PrEP ao HIV em homens que fazem sexo com homens, foram descongeladas para análise da ativação de linfócitos T. Trinta e quatro participantes com swab anorretal positivo para CT e/ou NG foram selecionados, enquanto assintomáticos e negativos para outras ISTs. Trinta e cinco controles foram selecionados randomicamente. Encontramos uma maior frequência de linfócitos T CD8+ HLA-DR+CD38+ (1,5 vs. 0,9% p < 0,005) no grupo com infecção assintomática. Os linfócitos T CD8+ de memória também apresentaram uma maior expressão dos marcadores de ativação. Os marcadores de exaustão e senescência foram significantemente mais expressos no grupo com a infecção. Não foi observado aumento ou diferença nos níveis de CD14 solúvel no plasma. Nossos achados demonstram que as infecções anorretais assintomáticas por CT e NG induzem a ativação sistêmica de linfócitos T CD8+. Considerando a alta prevalência dessas infecções e o risco associado de aquisição da infecção pelo HIV-1, o rastreamento periódico e o tratamento sistemático devem sem explorados em conjunto com as estratégias de prevenção ao HIV / Oral antiretroviral pre-exposure prophylaxis (PrEP) has been established as a pivotal strategy in the prevention against HIV epidemic. However, the incidence of HIV-1 infections has been rising among the youth, as well as other sexually transmitted infections (STIs), acting as an important risk factor for HIV-1 acquisition. Infection by Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) are among the most diagnosed. Although the presence of mucosal lesions is a known risk factor for HIV-1 acquisition, the potential increase in risk associated with asymptomatic STIs is not completely understood. Recent data defined higher T cell activation as a single risk factor for sexually acquired HIV-1 infection. We examined the effect of asymptomatic CT and/or NG anorectal infection on immune activation. Peripheral blood mononuclear cells from participants of PrEP Brasil, a study of daily oral PrEP among healthy men who have sex with men, were analyzed for T cell activation by flow cytometry. Thirty-four participants with positive anorectal swab for CT and/or NG were selected, while negative for other STIs and without any reported symptoms. Thirty-five controls were randomly selected. We found a higher frequency of CD8+ HLA-DR+CD38+ T cells (1.5 vs. 0.9% p < 0.005) in the group with CT and/or NG infection and a greater median proportions of activation markers expression in CD8+ T cells with memory phenotype. Exhaustion and senescence markers were also significant higher in the infected group. No difference was observed in the soluble CD14 levels. Our findings suggest that asymptomatic CT and NG anorectal infection lead to a systemic activation of the T cell compartment. Considering the high prevalence of asymptomatic infection and the risk of HIV-1 acquisition associated, regular screening and treatment should be explored as an adjuvant tool for HIV prevention

A profilaxia pré-exposição (PrEP) ao HIV se consolidou como uma importante estratégia de combate ao avanço da epidemia. Ainda assim, a incidência de casos da infecção vem aumentando na população jovem, assim como a de outras infecções sexualmente transmissíveis (ISTs), que atuam como importante fator de risco para transmissão do HIV-1. Entre as infecções mais frequentemente diagnosticadas estão Chlamydia trachomatis (CT) e Neisseria gonorrhoeae (NG). A presença de lesões na mucosa genital e anal são fatores de risco estabelecidos para a transmissão do HIV-1, porém o impacto das infecções assintomáticas ainda é pouco conhecido. Dados recentes mostram que a ativação sistêmica de linfócitos T é um fator de risco para a aquisição da infecção pelo HIV-1. Nesse estudo, estudamos a ativação de linfócitos T na presença de infecção anorretal assintomática por CT e/ou NG. Células mononucleares do sangue periférico de voluntários do PrEP Brasil, um estudo clínico demonstrativo de PrEP ao HIV em homens que fazem sexo com homens, foram descongeladas para análise da ativação de linfócitos T. Trinta e quatro participantes com swab anorretal positivo para CT e/ou NG foram selecionados, enquanto assintomáticos e negativos para outras ISTs. Trinta e cinco controles foram selecionados randomicamente. Encontramos uma maior frequência de linfócitos T CD8+ HLA-DR+CD38+ (1,5 vs. 0,9% p < 0,005) no grupo com infecção assintomática. Os linfócitos T CD8+ de memória também apresentaram uma maior expressão dos marcadores de ativação. Os marcadores de exaustão e senescência foram significantemente mais expressos no grupo com a infecção. Não foi observado aumento ou diferença nos níveis de CD14 solúvel no plasma. Nossos achados demonstram que as infecções anorretais assintomáticas por CT e NG induzem a ativação sistêmica de linfócitos T CD8+. Considerando a alta prevalência dessas infecções e o risco associado de aquisição da infecção pelo HIV-1, o rastreamento periódico e o tratamento sistemático devem sem explorados em conjunto com as estratégias de prevenção ao HIV / Oral antiretroviral pre-exposure prophylaxis (PrEP) has been established as a pivotal strategy in the prevention against HIV epidemic. However, the incidence of HIV-1 infections has been rising among the youth, as well as other sexually transmitted infections (STIs), acting as an important risk factor for HIV-1 acquisition. Infection by Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) are among the most diagnosed. Although the presence of mucosal lesions is a known risk factor for HIV-1 acquisition, the potential increase in risk associated with asymptomatic STIs is not completely understood. Recent data defined higher T cell activation as a single risk factor for sexually acquired HIV-1 infection. We examined the effect of asymptomatic CT and/or NG anorectal infection on immune activation. Peripheral blood mononuclear cells from participants of PrEP Brasil, a study of daily oral PrEP among healthy men who have sex with men, were analyzed for T cell activation by flow cytometry. Thirty-four participants with positive anorectal swab for CT and/or NG were selected, while negative for other STIs and without any reported symptoms. Thirty-five controls were randomly selected. We found a higher frequency of CD8+ HLA-DR+CD38+ T cells (1.5 vs. 0.9% p < 0.005) in the group with CT and/or NG infection and a greater median proportions of activation markers expression in CD8+ T cells with memory phenotype. Exhaustion and senescence markers were also significant higher in the infected group. No difference was observed in the soluble CD14 levels. Our findings suggest that asymptomatic CT and NG anorectal infection lead to a systemic activation of the T cell compartment. Considering the high prevalence of asymptomatic infection and the risk of HIV-1 acquisition associated, regular screening and treatment should be explored as an adjuvant tool for HIV prevention

Introdução: Como a terapia antirretroviral (TARV) atualmente permite que um número maior de crianças infectadas pelo HIV atinja a idade adulta, passam ser relevante questões como a imunossenescência precoce e a exaustão celular, semelhante ao observado em adultos infectados pelo HIV. Objetivos: Avaliar se a idade de início da TARV modifica os padrões de ativação imune, senescência e resposta vacinal em crianças infectadas perinatalmente pelo HIV. Desenho do estudo: Estudo transversal, exploratório. Métodos: Obtivemos dados de prontuários de pacientes e cartões de imunização e coletamos sangue para sorologias e isolamento de células mononucleares do sangue periférico (CMSP). Os critérios de elegibilidade incluíram: idade < 18 anos, TARV por pelo menos 6 meses e carga viral < 50 cópias/mL. Anticorpos de proteção (Ac) para Hepatite A e B, Rubéola e Caxumba foram medidos. Células T com marcadores de senescência (CD57 +), anergia (CD28-), apoptose (CD95 +), ativação (CD38 +, CCR5 +, HLA-DR +) e exaustão (PD-1 +) foram analisadas por citometria de fluxo. Resultados: foram incluídas 56 crianças, com idade mediana de 12 anos e tempo mediano de TARV de 9 anos. A mediana das contagens de LTCD4 + foi de 1010 células/mm3 (%mediano = 36,7%) e a média da razão LTCD4+/LTCD8+ foi de 1,6. A proteção das vacinas foi a seguinte: 80% para Hepatite A, 64% para Hepatite B, 57% para Rubéola e 44% para Caxumba. A idade mais precoce de início da TARV se correlacionou negativamente com LTCD4+ mais altos, LTCD4+ Nadir mais alto, maior razão LTCD4+/LTCD8+ e maiores títulos de Ac para a caxumba e a rubéola. Houve correlação positiva da idade de início de TARV e marcadores de ativação, apoptose, senescência e exaustão em LTCD4+ e LTCD8+. Tais marcadores se relacionaram com pior resposta vacinal. Houve benefício em crianças iniciando TARV < 6m na preservação da homeostase e resposta imune. Conclusão: Houve benefícios do início precoce da TARV na preservação de LTCD4+ e da resposta vacinal, e na prevenção da maturação e senescência imune neste grupo de crianças perinatalmente infectadas pelo HIV. / Background: As successful antiretroviral therapy (ART) allows a larger number of HIV-infected children to reach adulthood, issues such as early immune senescence and exhaustion arise, similar to what is seen in HIV-infected adults. Objectives: To evaluate whether time of ART initiation modified patterns of immune activation, senescence and vaccine response in PHIC Design: Cross-sectional, exploratory study. Methods: We obtained data from patient charts and immunization cards, and collected blood for serology and peripheral blood mononuclear cells (PBMC) isolation. Eligibility criteria included age < 18 years, ART for at least 6 months and viral load < 50 RNA copies/mL. Protective antibodies (Ab) for Hepatitis A and B, Rubella and Mumps were measured. T cells with markers for senescence (CD57+), anergy (CD28-), apoptosis (CD95+), activation (CD38+, CCR5+, HLA-DR+) and exhaustion (PD-1+) were analyzed by flow cytometry. Results: 56 children were included: their median age was 12 years and median time on ART was 9 years. Median LTCD4+ counts were 1010 cells/mm3 (median % 36,7%) and mean LTCD4+/LTCD8+ ratio was 1.6. Vaccine protection was as follows: 80% for Hepatitis A, 64% for Hepatitis B, 57% for Rubella and 44% for Mumps. Earlier age at ART initiation was negatively correlated with higher LTCD4+, higher nadir LTCD4+, higher LTCD4+/LTCD8+ ratio, and higher Ab titers for Mumps and Rubella. There was positive correlation of age at ART initiation and activation, apoptosis, senescence and exhaustion markers in LTCD4+ and LTCD8+. Markers correlated with poorer vaccine response. There was benefit in children starting ART < 6m in preserving immune homeostasis and response. Conclusion: There were benefits of early ART initiation in preserving LTCD4+ and vaccine response, and in preventing immune maturation and senescence in this group of PHIC