Metronomic cyclophosphamide (CPA) treatment activates robust anti-tumor immunity and induces regression of implanted tumors in mouse models of brain cancer when administered on an intermittent, every 6-day schedule (CPA/6d), but not on a daily low-dose or a maximum-tolerated dose schedule. Five intermittent metronomic CPA schedules were investigated in GL261 gliomas implanted in scid mice. Metronomic CPA treatments spaced 9 or 12 days apart induced extensive tumor regression, however, tumor-infiltrating natural killer cell responses were not sustained, and tumor growth rapidly resumed after treatment day 24. Increasing the CPA dose prolonged the period of tumor regression on the every 9-day schedule, but natural killer cell activation was markedly decreased. Thus, sustained immune and anti-tumor responses were only achieved on the CPA/6d schedule. Furthermore, CPA/6d treatment eradicated GL261 tumors implanted in immunocompetent C57BL/6 mice by activating anti-tumor CD8-T cell responses and immune memory, which provides proof-of-concept that single agent chemotherapy delivered on an optimized metronomic schedule can cure large established cancers. Transcriptomic profiling, KEGG pathway, and upstream regulator analysis were employed to compare CPA/6d-induced gene expression changes between: immune-responsive GL261 tumors and immune-unresponsive Lewis lung carcinoma (LLC) and B16F10 melanoma tumors; between GL261 tumors implanted in immunocompetent mice versus in scid immunodeficient mice; and between GL261 tumors in scid mice treated with CPA every 6-days or every 9-days. CPA-treated LLC tumors were associated with inhibited VEGFA-targeted genes, down-regulated cell adhesion and transendothelial migration genes, and up-regulated drug metabolism pathways. In B16F10 tumors, CPA activated genes in chemokine signaling and antigen processing and presentation pathways, but no NK cell and T cell effector pathways were activated. GL261 tumors in scid mice were deficient in CPA activation of a subset of cytokine and cytokine receptor genes and T cell receptor signaling genes seen in immunocompetent mice. Cytokine gene expression was lower and drug metabolism gene expression was higher in every 9-day CPA-treated tumors versus CPA/6d-treated tumors. Together, these studies elucidate the dose, schedule, and adaptive immune-dependence of CPA-induced anti-tumor immune responses, giving new insight into the molecular signaling events underlying the deficiencies in immune responses seen in intermittent metronomic CPA-unresponsive tumor models. / 2017-05-31T00:00:00Z

Immunologische Gedächtnisreaktionen sind die Grundlage um wiederkehrende Erreger schnell und effizient zu bekämpfen und um einen Impfschutz zu generieren. Das zellvermittelte Gedächtnis wird unter anderem durch CD8 Gedächtnis-T-Zellen aufgebaut, welche vor allem im Kontext von Immunreaktionen gegen intrazellulärer Erreger vonnöten sind, um bei Reinfektion mit den Erregerstämmen einen schnellen Schutz zu gewährleisten. Ein detailliertes Wissen über die Generierung, Kontrolle und Reaktivierung der Gedächtniszellen ist nützlich, um Gedächtnisreaktionen verstehen und lenken zu können. Durch die Entdeckung des TZR und CD28 wurden Meilensteine für das Verständnis der T-Zellaktivierung gelegt und die Grundlage geschaffen, CD8 Gedächtnisreaktionen zu verstehen. Auch wenn für primäre Immunreaktionen die „2-Signal-Theorie“ lange als erwiesen gilt, so blieb die Rolle der Kostimulation für Gedächtnisreaktionen lange umstritten. In dieser Arbeit wurden verschiedene methodische Herangehensweisen verwendet, mit denen durchgehend die Bedeutung von CD28 vermittelter Kostimulation für immunologische CD8 T-Zell-Gedächtnisreaktionen nachgewiesen wurde. CD28 blockierende Antikörper und CD28 induzierbar deletierbare Mauslinien wurden im Modellinfektionssystem mit Ovalbumin produzierenden Listeria monocytogenes zur Analyse der Primär- und Sekundärantworten verwendet. Mit diesen Methoden konnte eine Beeinträchtigung der Expansion von CD8 Gedächtniszellen in Abwesenheit von CD28 bewiesen werden. Weiterhin werden Effektorfunktionen wie Degranulation und Produktion von IFN-γ während der Sekundärinfektion in Abwesenheit von Kostimulation eingeschränkt. Mit Hilfe von Experimenten, bei denen CD28 suffizienten Mäusen eine geringe Anzahl an naiven, antigenspezifischen, CD28 deletierbaren CD8 T-Zellen transferiert wurden, wurde die Bedeutung der Kostimulation für die Expansion von Gedächtniszellen bestätigt, jedoch konnte überraschenderweise auch ein Anstieg der Effektorfunktionen in Abwesenheit von CD28 sowohl während der Primär- als auch der Sekundärantwort dokumentiert werden. Diese zur globalen Blockade bzw. Deletion widersprüchlichen Ergebnisse lassen eine Beteiligung anderer CD28 abhängiger Zelltypen an der Induktion der Effektorfunktionen der CD8 T-Zellen plausibel erscheinen, wie zum Beispiel Einflüsse von T-Helferzellen, welche die Effektorfunktionen positiv verstärken, solange sie selbst Kostimulationssignale empfangen können. Weiterhin konnte gezeigt werden, dass sich Gedächtniszellen an den CD28 defizienten Phänotyp – eine CD28 intakte immunologische Umgebung vorausgesetzt – adaptieren können, wenn ausreichend Zeit nach Deletion und vor Sekundärinfektion verstreichen konnte. / Immunological memory is of vital importance for the fight against reoccurring pathogens and to protect organisms from infections. Important players are CD8 memory T-cells that are created mainly during intracellular infections to boost rapid cellular defenses upon reinfection. The understanding of the generation, control and reactivation of these memory cells is crucial to comprehend and regulate mechanisms of memory immune reactions. The discovery of the TCR and of the costimulator CD28 depict important milestones towards the understanding of activation of memory cells – and naive cells, of course. The paradigm of the two signal theory in the activation of naive T-cells has long been accepted but the role of CD28 mediated costimulation in secondary CD8 T-cell responses remains controversial. Several methodological approaches to investigate the impact of costimulation on memory CD8 T-cells were used in this work, all proving the importance of CD28 to mount robust memory responses. CD28 blocking antibodies and also inducibly CD28 deleting mice were used in both primary and secondary infections with Ovalbumin-producing Listeria monocytogenes to establish an impaired clonal expansion of CD8 memory T-cells in the absence of CD28 function. Furthermore, effector functions such as degranulation and IFN-γ production were reduced during the secondary immune response. Specific deletion of CD28 in CD8 cells in mice that were seeded with a naturally occuring number of antigen specific, CD28 deletable naive CD8 T-cells provided evidence for the importance of costimulatory signals for the clonal expansion but also revealed an increase of effector functions in the absence of CD28 both in the primary and in the secondary response. These findings suggest a participation of other CD28 responsive cells such as T-helper cells by supporting CD28 deleted effector cells to exert their effector functions under the terms of CD28 sufficiency in the other parts of the immune system. Furthermore, I found that the progeny of primed CD8 T-cells can adapt to the CD28 deficient phenotype if given sufficient time before reactivation.

Immune thrombocytopenia (ITP) is an autoimmune bleeding disorder characterized by a low platelet count (less than 100 x 10^9 platelets/L) and an increased risk of bleeding. ITP is difficult to diagnose and manage due to the deficiencies in our understanding of the pathophysiological mechanisms leading to thrombocytopenia. Anti-platelet autoantibodies are believed to be the primary mechanism of thrombocytopenia in ITP. In this thesis, I demonstrate that autoantibodies can only be detected in half of all ITP patients; therefore, other mechanisms should be investigated. CD8+ T cells have been implicated as a mechanism of disease in ITP, but platelet-specific CD8+ T cells have yet to be identified. I have characterized CD8+ T cells in ITP patients and found that platelet-specific CD8+ T cells can be detected in ITP patients. These platelet-specific CD8+ T cells can also be detected in healthy individuals, so they are not specific to ITP. However, regulatory defects were observed in ITP patients and CD8+ T cell activity was elevated in ITP patients relative to healthy individuals and thrombocytopenic non-ITP patients. Investigating whether platelet-specific CD8+ T cells can actively participate in platelet destruction and underproduction will be an essential step towards better understanding the role of CD8+ T cells as a disease mechanism in ITP, which will lead to improvements in the management of ITP. / Thesis / Doctor of Philosophy (PhD) / Platelets are small blood cells that are involved in minimizing blood loss at the site of a wound by forming a plug. In a disease called immune thrombocytopenia (ITP), patients have a low platelet count, which can result in bleeding. The bleeding symptoms of ITP decrease the quality of life for ITP patients and can be life-threatening in rare cases. It is believed that ITP is caused by proteins produced by the immune system called antibodies. I found that the antibodies that cause ITP can only be detected in half of all ITP patients. Therefore, there are probably additional causes of ITP. It is suspected that CD8+ T cells might cause ITP in some patients. CD8+ T cells are part of the immune system and they typically destroy other cells that are cancerous or infected by viruses. CD8+ T cells might also destroy healthy cells, like platelets. My goal was to characterize CD8+ T cells in order to determine their role in ITP. I found that CD8+ T cells from ITP patients can target platelets, and that healthy people have these CD8+ T cells as well. In regard to CD8+ T cells that target platelets, the difference between ITP patients and healthy people appears to be related to immune system regulation and CD8+ T cell activity. In the future, we should focus on understanding how platelet-specific CD8+ T cells can cause a low platelet count in order to improve the clinical management of ITP.

No description available.

No description available.

Existe un grupo de enteropatía conocidas como AVSN que pueden simular enfermedad celíaca. Objetivo: El objetivo de este estudio es describir los hallazgos histológicos y de inmunohistoquímica en pacientes con enfermedad celíaca y AVSN. Material y métodos: 15 biopsias de pacientes con enfermedad celíaca y 19 biopsias con AVSN fueron reexaminados. Se estudió características histológicas tales como atrofia severa, hiperplasia de criptas, número de células plasmáticas, número de eosinófilos y presencia de neutrófilos. Asimismo, a través de inmunohistoquímica se estudió la presencia de linfocitos CD4, CD8, CD3, CD56. Resultados: Se encontró diferencia significativa en la mayor presencia de hiperplasia de criptas (p=0,0348) y mayor número de células plasmáticas (p=0,0348) en las biopsias de enfermedad celíaca que en las catalogadas como AVSN. El número de linfocitos CD8, CD4, CD56 y su distribución fue similar en ambos grupos. El porcentaje de linfocitos intraepiteliales CD3 positivos (p=0,0144) fue mayor en pacientes con AVSN. Conclusión: Los hallazgos histológicos e inmunohistoquímicos muestran más similitudes que diferencias. La diferencia hallada en nuestro estudio sugiere mayor respuesta inmune humoral en pacientes con enfermedad celiaca que en AVSN. / There is a group of enteropathies recently known as seronegative villous atrophy (SNVA), which can simulate celiac disease. Objective: The aim of this study was to describe histological and immunohistochemical differences between a group of Celiac disease and SNVA patients. Material and methods: Microscopy reexamination and Immunohistochemistry study were performed for a group of 15 celiac patients and 19 SNVA patients. Histological features as severe atrophy, crypt hyperplasia, plasma cells number, eosinophils number, neutrophils presence were studied; CD4, CD8, CD3, and CD56 markers were studied through immunohistochemistry. Results: There was a significant difference between the frequency of observation of crypt hyperplasia (p=0.0348) and plasma cells (p=0.0348) in celiac disease patients than SNVA patients. In celiac disease was bigger. The number and distribution of CD 8, CD4 and CD56 lymphocytes was similar in both groups. The percentage of CD3 positive intraepithelial lymphocytes (p=0.0144) was higher in SNVA. Conclusion: Histological and immunohistochemical evaluation shows more similarities than differences. The differences found in this study suggest more humoral immune response in celiac disease than in SNVA.

O câncer cervical é o segundo maior responsável por mortes atribuídas a câncer em mulheres e dados epidemiológicos tem demonstrado a associação entre a infecção do HPV e o desenvolvimento da neoplasia. Sabe-se que num dado momento da infecção pelo HPV, ocorre integração do genoma viral ao genoma da célula hospedeira e consequente hiperexpressão de dois oncogenes virais, E6 e E7, o que contribui fortemente para a transformação celular. O presente trabalho propõe o uso de vacinas terapêuticas expressando a oncoproteína E7 do HPV-16 geneticamente fusionada à porção amino terminal da flagelina FliCd de Salmonella enterica sv müenchen; e verificação de seu possível papel adjuvante. Vacinas de DNA foram construídas de modo a direcionar as proteínas hibridas ao espaço intracitoplasmático. A verificação da expressão in vitro foi feita utilizando transfecções de culturas celulares, seguida de imunofluorescência e imunodetecção. Em seguida, essas construções vacinais foram administradas em camundongos C57BL6. Ensaios de ELISPOT foram feitos para mensuração o nível de linfócitos T secretores de IFN-g. Os dados de imunofluorescência e imunodetecção demonstraram a correta expressão da proteína. Ensaios de proteção realizados com 5 x 106 células TC-1 administrada por via subcutânea mostraram 80% de proteção em camundongos que haviam recebido previamente 4 doses das vacinas de DNA por biobalística. Ensaios de ELISPOT mostraram em média 9 células do baço secretoras de IFN-g por 106 células do baço (INF-g+/106) responsivas ao peptídeo CD8 / E7 de forma específica. Nossos dados sugerem que a formulação vacinal possui um efeito terapêutico significativo frente ao desafio com as células tumorais TC-1. Em paralelo, foi construída a cepa de salmonela vacinal SL FlaE7 que não mostrou efeito protetor frente ao desafio com células TC-1. / The cervical cancer is the second major responsible for deaths attributed to cancer in women and epidemiologic data have been demonstrating the association between the infection of HPV and the development of this illness. It is known that in a certain moment of the infection with HPV, occurs the integration of the viral genome in the genome of the host cell and consequent over expression of two oncogenes, E6 and E7, it strongly contributes to the transformation of that cell. The present work proposes the use of DNA vaccines expressing the oncoprotein E7 of HPV-16 genetically fused to the portion A-terminal of the flagellin FliCd of Salmonella enterica sv müencheun and verification of your possible performance as adjuvant. The DNA vaccines were constructed in expression vector for eukaryotic to address the hybrid proteins to the intracitoplasmatic space. The verification of the expression in vitro was made using transfections of cellular cultures (COS-7) followed by immunofluorescence and western blot analyses. Soon after, those vaccines were injected in mice C57BL6 that were challenged then with 5^105 tumor cells TC-1 subcutaneous. ELISPOT assays were performed for measure the level of spleen cells secreting interferon g. The immunofluorescence and Western blot data are complementary demonstrating the correct expression of the protein. Protection assays showed 80% of protection in mice that had previously received 4 doses of the DNA vaccines in gene gun form. Assays of ELISPOT show 9 cells of the spleen secreting of IFN-g (average) for 106 cells of the spleen (INF-g /106). Our data suggest that the formulation of vaccines possesses a significant therapeutic effect front to the challenge with the tumor cells TC-1 accompanist splenocyte IFN-g secretory.

BIM é uma proteína pro-apoptótica membro da família Bcl-2. No sistema imunológico, BIM foi descrita como reguladora da homeostase de linfócitos. Porém, ainda não foi estudado o papel do BIM no estabelecimento da resposta imune de linfócitos T CD8+. Sendo que os vetores adenovirais fortes ativadores da resposta, neste trabalho investigamos o papel de BIM na qualidade e frequência de linfócitos T CD8+ estimulados com Ad.cOVA. Camundongos C57Bl/6 selvagens, bim+/- e bim-/- foram imunizados com 2x106 PFU/100μl. Assim, observou-se uma redução da lise especifica e menor freqüência de linfócitos CD8+ produtores de IFNγ em camundongos bim-/-. Em paralelo, foi avaliada a resposta imune anti-tumoral destes camundongos sem encontrar diferencias significativas. A cinética da resposta efetora de linfócitos T CD8+ de camundongos bim-/- mostrou escassa perda das capacidades efetoras destes linfócitos, sendo o possível mecanismo para controlar a progressão tumoral. Em conclusão camundongos bim-/- apresentam uma menor freqüência de células efetoras, sugerindo um importante papel de BIM na produção de linfócitos T CD8+ antígeno-específicos trás a vacinação com Ad.cOVA. / BIM is a pro-apoptotic member of the Bcl-2 protein family. In the immune system, BIM has been described as lymphocyte homeostasis regulator. However, the role of BIM in the establishment of the immune response of CD8+ T lymphocytes has not yet been studied. As the strong adenoviral vectors activating the response, we investigated the role of BIM in the quality and frequency of Ad.cOVA-stimulated CD8+ T lymphocytes. Wild C57Bl/6 mice, bim+/- and bim-/- were immunized with 2x106 PFU/100μl. Thus, a reduction of the specific lysis and decreased frequency of IFNγ producing CD8+ lymphocytes in bim-/- mice was observed. In parallel, the anti-tumor immune response of these mice was evaluated without finding significant differences. The kinetics of the effector response of CD8+ T lymphocytes from bim-/- mice showed little loss of the effector capacities of these lymphocytes, being the possible mechanism to control tumor progression. In conclusion, bim-/- mice show a lower frequency of effector cells, suggesting an important role of BIM in the production of antigen-specific CD8+ T lymphocytes after vaccination with Ad.cOVA.

O controle do parasita na fase crônica da infecção por Trypanosoma cruzi se dá principalmente por uma resposta mediada por anticorpos, uma resposta celular TH1 e uma resposta mediada por linfócitos T CD8. Na fase crônica, co-existem linfócitos T CD8 com fenótipo CD8Low CD45RCLow (CD8LL que apresentam marcadores de células sensibilizadas pelo antígeno) junto com células CD8High CD45RCHigh (CD8HH, que em grande parte apresentam fenótipo de célula naive). Células CD8High CD45RCLow (CD8HL) podem ser também observadas. As células CD8LL se apresentam no camundongo independente da cepa de T. cruzi infectante. Verificou-se que na sua grande maioria as células CD8LL tem fenótipo de células em repouso, baixa expressão de CD62L baixa expressão de CD127 (CD62LLOWCD127LOW), sendo estas as características de células efetoras de memória (EM). Este tipo celular ainda pode chegar a expressar marcadores de células NK de significado incerto. Observa-se, na análise funcional, que na estimulação in vitro das células CD8 com anticorpos anti-CD3/CD28 há uma recuperação baixa de CD8 por provável morte por AICD. Este fato é reforçado pelo aumento da ligação à anexina nas células sobreviventes, bem como através da expressão de CD69. Estudos anteriores relataram que o número de células CD8 diminuía após desafio in vivo com o parasita; porém o observado foi uma diminuição das células CD8LL na estimulação inespecífica in vivo com Poli-IC, um ligante de TLR-3. O desafio in vivo com antígeno de tripanossoma na cavidade pleural ocasiona uma migração preferencial de células CD8 e entre estas migram células de fenótipos CD8LL e CD8HL. No entanto, ao contrário do esperado, este estímulo resulta em uma diminuição da expressão de CD69 nas células CD8 infiltrantes. Visando determinar in vivo o papel protetor das células CD8, em um primeiro momento células de baço total foram tranferidas para camundongos sadios e, após a infecção com T. cruzi, observou-se um controle parcial da infecção, caracterizado por um retardo no pico de parasitemia e diminuição na intensidade de infecção, evidenciando um papel protetor parcial in vivo. Na determinação de fatores envolvidos na geração e manutenção das células CD8LL, observou-se que os camundongos deficientes em CD28, INOS ou CD4 têm geração normal de células CD8LL. Os camundongos IL-12p40-KO têm uma deficiência parcial na geração de células CD8LL. Já os camundongos deficientes em INF-gama, por sua vez, possuem uma deficiência acentuada destas células, apesar de que a diminuição poderia se dever a um aumento da necessidade periférica. Por outro lado, os camundongos IL-12p40-KO e INF-gama-KO desenvolvem um quadro neurológico sub-agudo progressivo, onde as células CD8 infiltrantes na medula espinhal apresentam um fenótipo misto CD8LL e CD8HL, e não são anérgicas, por sinal. / The control of the parasite in the chronic phase of infection by Trypanosoma cruzi occurs mainly by an antibody response mediated by a TH1 response and a cellular response mediated by CD8 T lymphocytes. In the chronic phase, co-exist with CD8 T lymphocyte phenotype CD8Low CD45RCLow (CD8LL showing markers of cells sensitized by antigen) with cell CD8High CD45RCHigh (CD8HH which have largely naive cell phenotype). Cells CD8High CD45RCLow (CD8HL) can also be observed. CD8LL cells were present in mice independent of the strain of T. cruzi infecting. It was found that in most cells CD8LL cell phenotype is at rest, low expression of CD62Llow expression of CD127 (CD62LLOWCD127LOW), which are the characteristics of effector memory cells (MS). This cell type can still get to express markers of NK cells of uncertain significance. There is, in functional analysis, which in vitro stimulation of CD8 cells with anti-CD3/CD28 antibodies there is a low recovery of CD8 by probable death IACD. This fact is reinforced by the increase in connection anexina cells survived, and through the expression of CD69. Previous studies reported that the number of CD8 cells decreased after in vivo challenge with the parasite, but the observed was a decrease in cell CD8LL the nonspecific stimulation in vivo with poly-IC, a ligand of TLR-3. The challenge with antigen in vivo of trypanosome in the pleural cavity causes a preferential migration of CD8 cells and between the migrating cells CD8LL phenotypes and CD8HL. However, unlike the expected, this stimulation results in a decrease in the expression of CD69 on CD8 cells infiltrating. To determine the in vivo protective role of CD8 cells in a first time total spleen cells were transferred to healthy mice and after infection with T. cruzi, there was a partial control of infection, characterized by a delay in peak parasitemia and decrease in intensity of infection, indicating a partial protective role in vivo. In determining the factors involved in the generation and maintenance of cells CD8LL, it was observed that mice deficient in CD28, iNOS and generation have normal CD4 cell CD8LL. The mouse IL-12p40-KO have a partial deficiency in the generation of cells CD8LL. But the mice deficient in INF-gamma, which in turn have a marked deficiency of these cells, although the decrease could be due to increased peripheral need. Moreover, the mice IL-12p40-KO and INF-gamma-KO develop a progressive neurological sub-acute, where the infiltrating CD8 cells in the spinal cord showed a mixed phenotype CD8LL and CD8HL, and are not anergic, by signal.

Orientador: Lenice do Rosário de Souza / Resumo: Segundo dados do Programa Conjunto das Nações Unidas sobre HIV/Aids (UNAIDS), existem atualmente 36,9 milhões de pessoas vivendo com HIV no mundo. A disponibilização e eficácia da terapia antirretroviral (TARV) permitiu uma mudança no cenário desta pandemia, reduzindo consideravelmente a mortalidade associada à aids. Devido à redução da carga viral plasmática do HIV (CV) para níveis indetectáveis, a TARV permite que ocorra a recuperação de células T CD4+, principal alvo do vírus, e melhora no prognóstico das pessoas que vivem com o HIV/aids (PVHA). Entretanto, as mudanças no compartimento de linfócitos T CD8+, responsáveis pelo controle da replicação viral, são relativamente pouco entendidas durante os vários estágios da infecção. Desta forma, o presente estudo, de caráter retrospectivo, teve o objetivo de avaliar, a partir do levantamento das contagens de células T CD8+, as possíveis correlações entre esta variável e a evolução clínica da infecção, considerando as contagens de células T CD4+, quantificações da CV, tempo de TARV, classe terapêutica utilizada, aparecimento de infecções oportunistas e desfecho clínico (paciente assintomático, progressão para aids ou morte). Para isso, foram analisados 200 prontuários eletrônicos de PVHA acompanhadas no Serviço de Ambulatórios Especializados de Infectologia “Domingos Alves Meira” (SAEI-DAM) e diagnosticadas a partir de 2012. Para a análise dos dados, foram realizados os testes, binomial negativa, correlação de Pearson e analisad... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre