Diss. (sammanfattning) Stockholm : Karol. inst. / Härtill 4 uppsatser.

Proefschrift Universiteit van Amsterdam. / Met bibliogr., lit. opg. - Met samenvatting in het Nederlands.

Identification of patients with suboptimal nutritional status allows for early treatment intervention. Currently, no definitive test of nutritional status exists. Therefore, this study was conducted to identify possible functional indicators of acute nutritional deprivation. The effects of total nutritional deprivation and subsequent refeeding on lymphocyte functions and subpopulations were examined in 23 healthy cats. Peripheral blood samples were analyzed at various times during fasting and refeeding periods. During the fasting period, decreases were observed in leukocyte number (day 4; p < 0.04), lymphocyte number (p < 0.02), CD4+ cells (day 4; p < 0.06), CD4:CD8 ratio (0 hours; p < 0.004), and mitogen stimulated CD4:CD8 ratio (72 hours; p < 0.15) during the fasting period as compared to baseline. Increases were seen in CD4+ cells (day 7; p < 0.09), CD8+ cells (day 7; p < 0.04) and intracellular calcium (day 4; p < 0.02) as compared to baseline. During the refeeding period increases (p < 0.05) were observed in leukocyte number, CD4+ cells, CD8+ cells, lymphocyte proliferation (p < 0.07) and lymphocyte number (p < 0.004) as compared to day 7. These findings suggest that 7 days starvation had immunosuppressive effects on cats which were alleviated during 7 days refeeding. The use of CD4:CD8 ratio in conjunction with intracellular calcium flux may be useful as indices of nutritional status. / Master of Science

Submitted by Ana Maria Fiscina Sampaio (fiscina@bahia.fiocruz.br) on 2013-11-06T19:03:45Z No. of bitstreams: 1 Daniel Huber Pessina Análise imuno fenotípica de animais nod estudo da proteção ao diabetes..pdf: 2399319 bytes, checksum: 3fc4e57719b71c97883626a074b31ce3 (MD5) / Made available in DSpace on 2013-11-06T19:03:45Z (GMT). No. of bitstreams: 1 Daniel Huber Pessina Análise imuno fenotípica de animais nod estudo da proteção ao diabetes..pdf: 2399319 bytes, checksum: 3fc4e57719b71c97883626a074b31ce3 (MD5) Previous issue date: 2013 / Universidade Federal da Bahia. Faculdade de Medicina da Bahia. Salvador, BA, Brasil / Fundação Oswaldo Cruz. Centro de Pesquisas Gonçalo Moniz. Salvador, BA, Brasil / Os animais NOD representam o principal modelo experimental de estudo do diabetes autoimune. Apesar do progressivo número de estudos realizados, muitos aspectos imunes da promoção e regulação desta doença continuam obscuros. Utilizando o modelo (pela primeira vez aqui descrito) de proteção induzida pelo T. cruzi, bem como o modelo de aceleração pela ciclofosfamida, fizemos um estudo imuno-fenotípico em animais NOD com o objetivo de elucidar mecanismos imunes responsáveis pela regulação do diabetes tipo I. Demonstramos que a infecção de camundongos NOD com o T. cruzi os protege do desenvolvimento do diabetes. Estes animais desenvolvem uma resposta ao parasita caracterizada por uma pobre expansão de células T CD8 efetoras, bem como uma menor migração destas para os sítios parasitários. Estudo do perfil de citocinas mostraram ainda uma reduzida produção inicial de IFN no baço, mas elevada produção tardia nos tecidos inflamados, comparado a animais BALB/c. Estes dados, associados a uma maior produção inicial de IL-10 por esplenócitos, justificam a maior susceptibilidade à infecção observada nos animais NOD. O estudo de populações celulares com atividade regulatória mostrou que há aumento de Treg no início da infecção. Contudo a proteção ao diabetes desencadeada pelo T. cruzi não se correlaciona ao número de células Treg, pois há uma redução destas ao longo da infecção. Este fato, associado à observação de que a ciclofosfamida é incapaz de induzir diabetes nos animais infectados, apontaram para um papel limitado destas células na proteção ao diabetes pelo T. cruzi. Entretanto, houve aumento de células Gr1+, e a depleção destas reverte a proteção ao diabetes causada pela infecção, além de induzir a expansão de células T CD8+ efetoras e sua produção de IFN. Verificamos ainda, que níveis aumentados da expressão de PD-L1 relacionaram-se com a proteção ao diabetes proporcionado pelo T. cruzi, enquanto níveis reduzidos se relacionaram ao seu desenvolvimento espontâneo. Contudo, o tratamento com ciclofosfamida não reduz a expressão de PD-L1 em linfócitos, mas induz rapidamente o diabetes em animais NOD não infectados e leva a uma drástica diminuição de células Tregs CD25+ esplênicas. Os resultados, aqui tomados em conjunto, apontam para um complexo mecanismo de controle do diabetes, que envolve diferentes populações celulares que atuam de maneira variada com o modelo estudado. / The NOD mice are the most used experimental model for the study of autoimmune diabetes. Despite progressive number of studies, many aspects about the immune regulation and disease onset remains unclear. Using our model (described here for the first time) of diabetes protection induced by T. cruzi, as well as cyclophosphamide acceleration, we performed a immunophenotypic analysis of NOD animals, aiming to elucidate the immune mechanisms responsible for regulation of type I diabetes. We demonstrated that infection of NOD mice with T. cruzi protects them from diabetes onset. These mice develop a poor expansion of effector CD8 T cells in response to parasite, and have lower percentage of those lymphocytes in inflammatory sites, when compared to BALB/c mice. Cytokine profile's analysis also revealed a reduced initial production of IFN in spleen, but high late production in inflamed tissues. Those data associated to an elevated production of IL-10 by spleen cells could explain the increased susceptibility observed in infected NOD mice. Further analysis showed an increased Treg cells rates early after infection, followed by a progressive reduction thereof along infection. This fact, coupled with the observation that cyclophosphamide is unable to induce diabetes in infected mice, indicates a limited role for these cells in diabetes protection by T. cruzi. However, increased Gr1 + cells numbers was also found in infected mice, and its depletion reverses the protection of diabetes related to infection. That reversion was associated to an expansion of effector CD8 + T cells and their production of IFN. We also found that increased expression of PD-L1 were also related to diabetes protection provided by T. cruzi infection, while low levels were related to spontaneous diabetes development. Treatment with cyclophosphamide however did not reduce PD-L1 expression on lymphocytes, despites rapidly set diabetes in NOD uninfected animals. On the other hand, cyclophosphamide leads to a drastic decrease of CD25 + Treg cells in the spleen of NOD mice. These results, taken together, point to a complex mechanism of diabetes control, which involves different cell populations acting variously with the model.

La compréhension récente des mécanismes impliqués dans l’échappement tumoral au système immunitaire est fondamentale. En effet, cela a permis le développement de nouvelles immunothérapies à l’origine de réponses prolongées chez les patients atteints par plusieurs types de cancers. Cependant, une majorité de patients répondent insuffisamment ou rechutent. Il est donc indispensable d’identifier les mécanismes de résistances aux immunothérapies, et de nouvelles cibles permettant d’augmenter l’activité de ces thérapeutiques.La Neuropiline-1 (Nrp1) est une glycoprotéine transmembranaire indispensable à de nombreux processus physiologiques tels que l’angiogénèse et la guidance axonale. Nous avons montré dans le laboratoire qu’elle était exprimée dans le système immunitaire, lors de la synapse immunologique puis sur les cellules T conventionnelles activées.L’objectif de ce travail était d’étudier le rôle de la Nrp1 dans la réponse anti tumorale des lymphocytes T CD8+ chez la souris et chez l’homme.Nous avons montré que la délétion de Nrp1 sur les cellules T CD8+ murines augmente la réponse anti tumorale et diminue la croissance tumorale. Les cellules T CD8+ murines délétées pour la Nrp1 ont des capacités effectrices augmentées. La Nrp1 ne pouvant pas signaliser de manière autonome, nous avons montré qu’elle forme un complexe avec PD-1 chez la souris et chez l’homme et qu’elle en module son activité. Enfin, nous avons observé un effet synergique entre l’inhibition de Nrp1 et de PD1 chez la souris, ouvrant la possibilité d’une efficacité clinique chez les patients. / T follicular helper (Tfh) cells play an essential role in the development of antigen-specific B cell immunity. Tfh cells regulate the differentiation and survival of activated B cells outside and inside germinal centers (GC) of secondary lymphoid organs. They act through cognate contacts with antigen-presenting B cells, but there is no current marker to specifically identify those Tfh cells which productively interact with B cells. Here we show that neuropilin 1 (Nrp1), a cell surface receptor, is selectively expressed by a subset of Tfh cells in human secondary lymphoid organs. Nrp1 expression on Tfh cells correlates with B cell differentiation in vivo and in vitro, is transient, and can be induced upon co-culture with autologous memory B cells in a cell contact-dependent manner. Comparative analysis of ex vivo Nrp1+ and Nrp1- Tfh cells reveals gene expression modulation during activation. Finally, Nrp1 is expressed by malignant Tfh-like cells in a severe case of angioimmunoblastic T-cell lymphoma (AITL) associated with elevated terminal B cell differentiation. Thus, Nrp1 is a specific marker of Tfh cells cognate activation in humans, which may prove useful as a prognostic factor and a therapeutic target in neoplastic diseases associated with Tfh cells activity.

Previous studies employing the generation of MHC-incompatible embryonic chicken chimaeras by injecting MHC-incompatible stem cells resulted in an unexpected finding. Chimaeras made late in gestation developed as adults a severe autoimmune syndrome resembling the human syndrome of Systemic Lupus Erythematosus. Work in our laboratory aims to understand the role of CD8 T cells in immunity and/or autoimmunity. We have tested a three-cell model of CD4 T cell activation and differentiation during the development of the immune response specific for MHC transplantation antigens in one way mixed lymphocyte reactions. Our model proposes that whether Th1 or Th2 immunity is generated depends on both the ratio of CD4:CD8 T cells specific for antigen at the initiation of the immune response and on the ability of antigens to coordinately induce both CD4 and CD8 T cells. Previous studies employing parent into F1 models of graft-versus-host disease in mice have shown that the injection of parental cells results in two distinct outcomes. Parental cells which do not have a sufficient number of CD8 T cells present produce an autoimmune syndrome characteristic of systemic lupus erythematosus and a chronic graft-versus-host disease mediated by a Th2 response. Conversely, the presence of an adequate number of CD8 T cells results in a Th1 immune response and acute graft-versus-host disease resulting in the death of the F1 host. Our findings indicate that the ratio of the number of CD4 T cells to the number of CD8 T cells present in the spleen is crucial in whether naive CD4 T cells differentiate into Th1 or Th2 cells. We refer to this ratio as the CD4:CD8 T cell ratio or CD4:CD8 ratio. Thus, the differentiation of naive CD4+ T cells towards a differentiated Th1 phenotype is critically dependent on the concomitant induction of CD8 T cells by the same antigen, driven by a low CD4:CD8 ratio. In contrast, inefficient induction of CD8 T cells during the initial priming of lymphocytes greatly facilitates the differentiation of CD4 T cells towards the Th2-type lineage, and occurs when the CD4:CD8 ratio is high. Given our findings on the significance of the ratio of CD4:CD8 T cells in the decision making process of CD4 differentiation stimulated by antigen, we hypothesized that different CD4: CD8 ratios at different stages of development might contribute to the immune response generated at these stages. We tested this hypothesis in mice by comparing the CD4:CD8 ratio in adults and neonates and the Th1/Th2 responses generated in vitro. This CD4:CD8 T cell ratio is significantly higher in neonates than adults resulting in predominant Th1 responses by adult spleen cells and Th1/Th2 responses by neonatal spleen cells as demonstrated by the ELISPOT assay. We have compared the CD4:CD8 T cell ratio of a large number of adult and neonatal spleens in several mouse strains and have studied it systematically in BALB/c and C57BL/6 mice by flow-cytometry. We have consistently found a 3-5 fold higher CD4:CD8 T cell ratio in neonates as compared to adults in the strains tested. Furthermore, we found that neonatal spleen cells generate a predominant Th2 response whereas adult spleen cells generate CD4 and CD8 Th1 immunity when activated under the same conditions. We have further studied the role of CD8 T cells in CD4 T cell differentiation by reconstructing the adult CD4:CD8 T cell ratio in neonatal spleen cells with age-matched, isolated CD8 T cells. We found that in these “CD4:CD8 ratio-reconstructed cultures”, the Th2/IL-4 immunity is suppressed with concomitant generation of Th1/IFN-γ immunity upon activation by allo-antigen. Additionally, we have characterized the phenotype of the T cell mediating Th1/IFNγ immunity in the “CD4:CD8 ratio reconstructed cultures” and we found that while CD8 T cells produce exclusively IFN-γ, CD4 T cells now produce IFN-γ rather than IL-4. We suggest that physiologically distinct CD4:CD8 ratios at different stages of life should be considered in designing protocols of neonatal vaccination against pathogens that are contained by Th1-type immunity upon infection as adults. Moreover, as elaborated in the discussion, our studies might be pertinent in understanding by which mechanism autoimmunity arises in some cases.

Submitted by Ana Maria Fiscina Sampaio (fiscina@bahia.fiocruz.br) on 2014-02-27T18:21:59Z No. of bitstreams: 1 Claire SS CD8+ granzyme b...pdf: 4914876 bytes, checksum: e54c8737a502be3105cd578fa7d10ef4 (MD5) / Made available in DSpace on 2014-02-27T18:21:59Z (GMT). No. of bitstreams: 1 Claire SS CD8+ granzyme b...pdf: 4914876 bytes, checksum: e54c8737a502be3105cd578fa7d10ef4 (MD5) Previous issue date: 2013 / Fundação Oswaldo Cruz. Centro de Pesquisa Gonçalo Moniz. Salvador, BA, Brasil / Universidade Federal da Bahia. Faculdade de Medicina. Salvador, BA, Brasil / Células T CD8+ são essenCIaIS na defesa contra vírus, mas pouco se sabe sobre a sua participação na defesa do hospedeiro contra parasitas, como a Leishmania. Nesse trabalho, investigou-se a participação das células T CD8+ no processo inflamatório e na indução da morte do parasita, bem como os perfis proteômicos das lesões dos pacientes com leishmaniose cutânea localizada (LCL) infectados por L. braziliensis. Observa-se uma alta porcentagem de células T CD8+ nas lesões dos pacientes com LCL, como sugerido pela maior frequência de células T CD8+CD45RO+ e células T CD8+CLA + em comparação com CMSP do próprio indivíduo. Após re-estimulação com L. braziliensis, a maioria das células T CD8+ presentes na lesão expressam marcadores citolíticos, CD 107a e Granzima B. Além disso, a co-cultura de macrófagos infectados com linfócitos T CD8+ resultou na libertação de granzima B. A utilização do inibidor da granzima B, assim como Z-V AO, Fas:Fc ou anti­ IFN-y não teve nenhum efeito sobre a morte do parasita. Por outro lado, a co-cultura de macrófagos infectados com células T CD4+ diminuiu a taxa de infecção, efeito que foi completamente revertido ao se utilizar o anti-IFN-y, enfatizando o papel determinante de células T CD4+IFN-/ na morte da Leishmania. Além disso, observou-se um total de 150 proteínas diferencialmente expressas entre as lesões de pacientes com LCL e as amostras de pele normal. Destas, cinquenta e nove proteínas foram identificadas. Entre elas, 13 apresentaram uma maior ou menor expressão nas amostras dos pacientes em relação a pele normal. Vinte e sete proteínas foram encontradas somente nas lesões dos pacientes e 18 somente nas amostras de pele normal. Essas proteínas foram associadas com processos de regulação biológica; incluindo apoptose, ciclo celular e resposta imune. Para explorar as interações entre as proteínas identificadas e as proteínas e os genes que poderiam ser afetados por elas, redes e sub-redes de interações foram geradas. Após análises de imuno-histoquímica, a presença de caspas e 9, caspase-3 e granzima B foi validada no sítio da lesão. A expressão da granzima B nas lesões dos pacientes correlacionou-se positivamente com a expressão da caspase 9 e a porcentagem de células positivas para TUNEL. Observou-se também uma maior porcentagem de células postivas para TUNEL expressando granzima B nas biópsias dos pacientes que apresentam um processo mais intenso de necrose. Além disso, a presença de granzime B, caspase 9 e caspase-3 foram correlacionados positivamente com o tamanho da, lesão. Neste estudo, podemos concluir que as células T CD8+Granzima B+ estão envolvidas na patogênese da L. braziliensis, através da ativação da apoptose no sítio inflamatório, favorecendo a progressão do dano tecidual observado nos pacientes com LCL. / CD8+ T cells are essential in the defense against virus, but little is known of their participation in the host defense against parasites, such as Leishmania. In the present study, we investigated the participation of CD8+ T cells in the inflammatory process and parasite killing, as well as proteome profiles in the biopsies from localized cutaneous leishmaniasis patients (LCL) infected by L. brazliensis. We found a higher percentage of CD8+ T cells in lesions of LCL patients, as suggested by the higher frequency of CD8+CD45RO+T cells and CD8+CLA +T cells compared to PBMC. Upon L. braziliensis-restimulation, most of CD8+T cells from the lesion expressed cytolytic markers, CDI07a and Granzyme B. Furthermore, co-culture of infected macrophages and CD8+T lymphocytes resuIted in release of granzyme B and the use of granzyme B inhibitor, as well as z-V AD, Fas:Fc or anti-IFN-y had no effect upon parasite killing. On the other hand, co-culture of infected macrophages with CD4+T cells strongly increased parasite killing, which was completely reversed by anti-IFN-y, pointing out the decisive role of CD4+IFN-y +T cells in parasite killing. Besides that, a total of 150 differentially expressed proteins were observed in the lesions of LCL patients and normal skin. Fifty-nine proteins were identified. Among them, 13 were up or down regulated in LCL lesions compared to normal skin, 27 proteins were unique in the lesions of LCL patients and 18 were unique in the normal skin samples. These proteins were associated with biological regulation, including apoptosis, cell cycle and immune response. To explore interactions between the identified proteins and proteins and genes that may be affected by them, networks and subnetworks were generated. After immunohistochemistry analyses, the presence of casp~~e 9, caspase 3 and granzyme B were validated in the lesions site. Granzyme B expression in the lesions of LCL patients positively correlated with caspase 9 expression and the percentage of TUNEL-positive cells. We also observed a significant higher percentage of TUNEL-positive cells and granzyme B expression in the biopsies of patients showing a more intense necrotic processo Besides that, the presence of granzime B, caspase 9 and caspas e 3 were positively correlated with the lesion size. In this study we can conclude that CD8+ Granzyme B+T cells are involved in the pathogenesis of L. braziliensis due to their cytotoxic potential to induce apoptotic mechanism in the inflammatory site that favors the progression oftissue damage observed in LCL patients.

Hintergrund: Prognoseeinschätzung und Therapieplanung des kolorektalen Karzinoms richten sich nach traditionellen Klassifikationen und Staging-Systemen (TNM). Fraglich bleibt, ob diese die Komplexität der Tumorbiologie erfassen. Immunologische Parameter wie Tumor-infiltrierende Lymphozyten und Enzyme des Tryptophan-Stoffwechsels wie die Indoleamin-2,3-Dioxygenase (IDO) gewinnen zunehmend an Bedeutung. Hinsichtlich der prognostischen Wertigkeit einer IDO1-Expression in Malignomen und vor allem beim kolorektalen Karzinom herrscht Uneinigkeit. In Bezug auf neoadjuvant vorbehandelte Malignome gibt es bislang keine Untersuchungen. Ziel: Ziel der Arbeit war es, die prognostische Rolle einer IDO1-Expression und CD8-T-Zell-Infiltration in Tumorproben von Patienten mit einem lokal fortgeschrittenen Rektumkarzinom nach neoadjuvanter Radiochemotherapie zu evaluieren sowie die Korrelationen mit klinisch-pathologischen Parametern und den Einfluss auf das Überleben zu untersuchen. Material und Methoden: Evaluiert wurde die Expression von IDO1 und CD8 durch immunhistochemische Färbungen in 106 Tumorgewebeproben von Patienten nach neoadjuvanter Radiochemotherapie. Die Immuninfiltration wurde im Stroma, an der Invasionsfront und innerhalb der Tumorzellen betrachtet und mit retrospektiv erhobenen klinisch-pathologischen Parametern korreliert. Ergebnis: Der IDO1-Gesamtscore korrelierte positiv mit dem CD8+-Gesamtscore. Eine hohe IDO1- bzw. CD8-Infiltration stellten sich als unabhängige prognostischer Marker für ein verbessertes rezidivfreies Überleben bzw. Gesamtüberleben dar. Diskussion: Die Studie zeigt, dass die Analyse des lokalen Immunphänotyps ein hilfreiches Instrument sein kann, um Prognosen und Therapieansätze für Patienten mit lokal fortgeschrittenem Rektumkarzinom nach neoadjuvanter Radiochemotherapie besser abschätzen und langfristig an unterschiedlichen Immunprofilen orientieren zu können. / Background: Prognosis and therapy for colorectal cancer are based on traditional classifications and staging systems (TNM). It remains questionable whether these capture the complexity of tumor biology. Immunological parameters such as tumor-infiltrating lymphocytes and enzymes of the tryptophan metabolism such as indoleamine-2,3-dioxygenase (IDO) are becoming increasingly important. There is still a disagreement about the prognostic value of IDO1 expression in malignancies. Objectives: In this study, we examined the prognostic role of indoleamine-2,3-Dioxygenase (IDO1) and infiltrating cytotoxic T lymphocytes (CD8+) in locally advanced rectal carcinomas after neoadjuvant chemoradiation. Material and methods: Expression of IDO1 and CD8+ was evaluated through immunohistochemistry in 106 archival tumor tissue samples from patients following neoadjuvant chemoradiation and radical resection. Results: A high IDO1- or CD8+-infiltration presented itself as an independent prognostic marker for an improved recurrence-free survival or overall survival. Conclusion: Analysis of the local CD8+ and IDO1-expression profile may be a helpful tool in predicting prognosis for patients with locally advanced rectal cancer following neoadjuvant chemoradiation.

No description available.

A CD8+ cell-mediated host defense relies on cognate killing of infected target cells and on local inflammation induced by the secretion of IFN-g. Using assays of single cell resolution, it was studied to what extent these two effector function of CD8+ cells are linked. Granzyme B (GzB) is stored in cytolytic granules of CD8+ cells and its secretion is induced by antigen recognition of these cells. Following entry into the cytosol GzB induces apoptosis in the target cells. It was measured whether GzB release by individual CD8+ cells is accompanied by the secretion of IFN-gƒnƒnand of other cytokines. HIV peptide libraries were tested on bulk peripheral blood mononuclear cells and on purified CD4+ and CD8+ cells obtained from HIV infected individuals. The library included a panel of previously defined HLA class I restricted HIV peptides and an overlapping 20-mer peptide-series that covered the entire gp120 molecule. To characterize the in vivo differentiation state of the T-cells, freshly isolated lymphocytes were tested in assays of 24h duration. The data showed that only ~20% of the peptides triggered the release of both GzB and IFN-g from CD8+ cells. The majority of the HIV peptides induced either GzB or IFN-g, ~40% in each category. The GzB positive, IFN-g negative CD8+ cells did not produce IL-4 or IL-5, which suggests that they do not correspond to Tc2 cells but represent a novel Tc1 subclass, which was termed Tc1c. Also the IFN-g positive, GzB negative CD8+ cell subpopulation represents a yet undefined CD8+ effector cell lineage that was termed Tc1b. Tc1b and Tc1c cells are likely to make different, possibly antagonistic contributions to the control of HIV infection. Since IFN-g activates HIV replication in latently infected macrophages, the secretion of this cytokine by Tc1b cells in the absence of killing may have adverse effects on the host defense. In contrast, cytolysis by Tc1c cells in the absence of IFN-g production might represent the protective class of response. Further studies in the field of Tc1 effector cell diversity should lead to valuable insights for management of infections and developing rationales for vaccine design. / Im Verlauf von Infektionskrankheiten basiert die Verteidigung durch CD8+-Zellen auf der direkten T&ouml;tung von infizierten Zellen &uuml;ber die Perforin/Granzyme-Kaskade und auf der Entz&uuml;ndungsbildung verursacht durch die Sekretion von Interferon-Gamma (IFN-g). In der vorliegenden Arbeit wurde die Granzyme B (GzB) Sezernierung als direkter Nachweis f&uuml;r das Abt&ouml;ten von Zellen und parallel die Produktion von IFN-g durch HIV peptid-spezifische T-Zellen in chronisch HIV-infizierten Patienten gemessen. Eine Auswahl von in vorhergehenden Arbeiten definierten HLA-Klasse-I spezifischen HIV-Peptiden und eine HIV-Peptide-Bibiliotek, bestehend aus sich &uuml;berlappenden 20-mer Peptiden, die das gesamte Gp120 Molek&uuml;l von HIV-1 darstellten, wurden benutzt, um T-Lymphozyten aus frisch von HIV-infizierten Patienten gewonnenen mononukle&auml;ren Zellen aufgereinigte CD8+-Zellen zu stimulieren. ELISPOT-Assays wurden benutzt, um die Sekretion von GzB und IFN-g mit einer Aufl&ouml;sung auf der Ebene der Einzelzelle zu messen. Nur ~20% der Peptide l&ouml;sten die Freisetzung von sowohl GzB als auch IFN-g von CD8+ Zellen aus. Die Mehrheit der Peptide induzierte entweder GzB oder IFN-g, je ~40% in der jeweiligen Kategorie. Granzyme B-positive Zellen produzierten in parallel gemessen kein IL-4 oder IL-5. Da sie aus diesem Grunde keine Tc2 Zellen darstellen, wurden sie als neue Untergruppe Tc1c definiert. Diese GzB+/IFN-g- CD8+ Zellen vermutlich eine durch Apoptose induziertes Absterben von infizierten Zellen ausl&ouml;sen, ohne gleichzeitig eine Entz&uuml;ndungsreaktion zu verursachen. Die GzB-/IFN-g+ CD8+-Zellen stellen ebenfalls eine neue bisher unbeschriebene Zelluntergruppe dar und wurden als Tc1b Zellen bezeichnet. Diese k&ouml;nnten Entz&uuml;ndungsreaktion verursachen, ohne gleichzeitig direkt das Abstreben von Zellen zu induzieren und im Verlauf der HIV Infektion eine antagonistische Rolle zu den Tc1c Zellen einnehmen. Diese Tc1-CD8+ Effektorzell-diversit&auml;t k&ouml;nnte die Implementierung und Feineinstellung von fundamental verschieden Verteidigungsstrategien gegen HIV und andere Infektionskrankheiten erm&ouml;glichen. Die hier vorgelegten Studien liefern eindeutige Indizien daf&uuml;r, dass es in HIV-Infizierten eine signifikante Population von GzB sezernierenden CD8+-Zellen gibt, die weder IFN-g noch IL-4 oder IL-5 produzieren und daher in der Lage sind, mit Hilfe der Perforin/Granzyme-Kaskade zu t&ouml;ten, ohne dabei klassische Tc1 oder Tc2-Zellen darzustellen. Die h&ouml;here Sensitivit&auml;t des GzB ELISPOT-Assays Zytotoxizit&auml;t im Vergleich zum Chromium-Release-Assay zu messen, bietet eine hilfreiche Methode zum besseren Verst&auml;ndnis CD8+-Zell vermittelter Immunit&auml;t. Die Ergebnisse f&uuml;hren zu der Schlussfolgerung, dass es im Menschen die von uns erstmals beschriebenen GzB+/IFN-g- und GzB-/IFN-g+ Untergruppen von CD8+-Zellen gibt. Aufgrund der verschiedenen Effektorfunktionen die diese vermutlich aus&uuml;ben, erscheint es wichtig ihre jeweiligen Anteile im Kampf gegen HIV und andere Infektionskrankheiten zu ermitteln. Bei der Beurteilung von Immunantworten, ausgel&ouml;st durch experimentelle HIV-Impfstoffe, d&uuml;rfte es sich als ausgesprochen wichtig erweisen, diese GzB produzierenden CD8+-Zellen neben den konventionell gemessenen IFN-g sezernierden CD8+-Zellen zu ber&uuml;cksichtigen. Diese Vorgehensweise sollte wertvolle Einblicke gew&auml;hren, in wie weit der jeweilige Ph&auml;notyp von Effektorzellen den h&ouml;heren oder effektiveren Schutz gew&auml;hrt und daher wertvolle Hilfe beim Management von Infektionen und im Bereich des Impfstoffdesign liefern.