This thesis examines the isolation and characterisation (biological and chemical) of polypeptides from plants. A fractionation protocol was developed and applied on 100 plant materials with the aim of isolating highly purified polypeptide fractions from small amounts of plant materials. The polypeptide fractions were analysed and evaluated for peptide content and biological activities. A multitarget functional bioassay was optimised as a method for detecting substances interacting with the inflammatory process of activated neutrophil granulocytes. In this assay, the neutrophil was challenged with an inflammatory mediator, N-formyl methionyl-leucyl-phenylalanine (fMLP), or with platelet activating factor (PAF), to induce exocytotic release of the enzyme elastase, which then was quantified by photometric determination of the product p-nitroanilide (pNA) formed from a chromogenic substrate for elastase. Of the tested extracts, 41% inhibited pNA formation more than 60%, and 3% stimulated formation. Phoratoxin B and four new peptides, phoratoxins C-F, were isolated from Phoradendron tomentosum. In addition, the cardiac glycoside digitoxin was isolated from Digitalis purpurea. All these substances expressed cytotoxicity and a neutrophil challenging activity. Phoratoxins C-F were similar to earlier described phoratoxins A and B, which belong to the group of thionins. All the peptides were evaluated for cytotoxicity in a human cell line panel. Phoratoxin C was the most potent towards the cell lines (mean IC50: 160 nM), and was therefore investigated further on tumour cells from patients. Correlation analysis of the log IC50 values indicated a mechanism of action different from clinically used archetypal cytotoxic drugs. Phoratoxin C also showed selective toxicity to the solid tumours when compared to the haematological cancer types. The phoratoxin C was 18 times more potent towards the solid tumour samples from breast cancer cells (87 nM) compared to the tested haematological malignancies. The structure-activity relationship concerning cytotoxicity was evaluated for digitoxin and related cardiac glycosides. Digitoxin was shown to be potent, with the average IC50 37 nM being within the therapeutic concentration used for cardiac congestion (13-45 nM). Digitoxin expressed selective toxicity towards solid tumours from patients compared to haematological malignancies.

No description available.

La transmission mère-enfant (TME) du VIH-1 est un des enjeux majeurs de la pandémie. Une meilleure compréhension de la réponse des lymphocytes T cytotoxiques CD8+ (LTC) VIH-spécifiques lors de la grossesse facilitera le design de stratégies optimales pour diminuer la TME. Notre objectif est donc de caractériser l’amplitude et la diversité de la reconnaissance antigénique des LTC VIH-spécifiques avant, pendant et après la grossesse chez des femmes infectées par le VIH-1. Nos résultats montrent pour la première fois que l’initiation et la progression de la grossesse, à elles seules, n'ont que peu d’influence sur l’amplitude et la diversité de la reconnaissance antigénique des réponses LTC en termes de production d’IFN‐. Ces résultats indiquent que les femmes infectées par le VIH conservent une immunocompétence durant leur grossesse, du moins dans le contexte d’un traitement antirétroviral efficace. Ceci pourrait éventuellement aider à promouvoir l’immunisation comme stratégie pour prévenir la TME du VIH‐1. / Mother-to-child transmission (MTCT) of HIV-1 is one of the major issues of the pandemic. Characterization of HIV-specific immunity during pregnancy, especially cytotoxic CD8+ T lymphocytes (CTL), will lead to a better understanding of HIV pathogenesis and facilitate design of optimal strategies to prevent MTCT. Our objective is to describe the magnitude and the breadth of antigen recognition of HIV-specific CTL responses before, throughout and after pregnancy in a group of HIV-infected women. Our results revealed for the first time that initiation of pregnancy by itself doesn’t change the magnitude of CTL responses in terms of IFN- production. These findings support the fact that HIV-infected women maintain immunocompetence throughout gestation, at least in the context of effective antiretroviral treatment. These results provide a novel understanding of the dynamics of HIV-specific CTL responses during pregnancy and may help to promote maternal immunization as a strategy to prevent MTCT of HIV-1.

No description available.

Les polymorphonucléaires neutrophiles (PMNs) représentent une arme primordiale dans la défense contre divers agents pathogènes; notamment les bactéries, les champignons, les cellules tumorales de même que les cellules infectées par des virus. Cependant, certaines pathologies reliées à l’inflammation chronique soulèvent l’implication des neutrophiles notamment dans l’arthrite rhumatoïde. La réponse inflammatoire persistante générée par l’activation et la survie des neutrophiles engendre une destruction des tissus environnants suite à la sécrétion non contrôlée de leurs produits cytotoxiques. Même si l’activation chronique des neutrophiles est néfaste dans plusieurs pathologies, elle pourrait s’avérer un bon outil en cas de neutropénie, comme c’est souvent le cas les patients ayant reçu des traitements de chimiothérapie. Ce projet fait suite aux travaux doctoraux de Lagraoui (1999). Il vise à identifier le(s) facteur(s) du liquide synovial qui augmente la survie des neutrophiles ainsi que le mécanisme d’action impliqué dans ce processus. Similairement au facteur semi-pur isolés par Lagraoui (1999), le milieu conditionné concentré (MCC) augmente la survie des PMNs de 75% (39% ± 9.5 vs 68% ± 2.5, p<0.01). Suivant le séquençage du MCC parallèlement au facteur semi-pur actif, deux protéines ont été identifiées à la fois dans le MCC et dans le facteur semi-pur soient : l’albumine et la fétuine. Notre projet vise donc à comparer les effets de l’albumine et de la fétuine à ceux du GM-CSF dans l’optique d’une thérapie alternative au GM-CSF en tant qu’adjuvant de chimiothérapie. La présence d’albumine, de fétuine ou de GM-CSF chez les PMNs incubés 24 heures avec la Mutamycin® induit une diminution du nombre de cellules en apoptose par rapport à la Mutamycin® (Ctrl : 43% ± 10; A : 74% ± 3; F : (82% ± 6 et GM : 74% ± 7; p<0.01). L’effet de l’albumine dépend de la voie de la kinase PI3 mais également celle la kinase ERK, alors que celle de la fétuine dépend de la kinase PI3. Similairement l’EPO, l’albumine et la fétuine supporte la différentiation des HSCs en précurseurs érythrocytaires de type BFU-E. Dans un modèle murin de chiomioprotection, l’albumine augmente la concentration cellulaire rapport au groupe contrôle des leukocytes de la rate (66 ±8 x106c/ml vs 81 ±16 x106c/ml) et du sang (3.6 ±0.4 x106c/ml vs 5.7 ±2.3 x106c/ml). Donc, in vitro, l’albumine et la fétuine sont comparables au GM-CSF au niveau fonctionalité et mécansimes d’action. Cependant, vu leur manque de spécificité, l’application thérapeutique en tant qu’adjuvant de chiomiothérapie de l’albumine et la fétuine est peu prometteuse. Par contre, les maladies dégénératives et les évènements ischémiques pourraient s’avérer de bonnes cibles thérapeutiques, principalement pour l’albumine. / Circulating polymorphonuclear neutrophils (PMN) possess a short half-life and are constantly renewed by the bone marrow to ensure the first-line of defense. Therefore, homeostasis must be maintained through a well-regulated process of apoptosis. Survival of PMN can be regulated by several cytokines as well as conditioned media (CM). Although PMN are crucial for protection against microorganisms, activated neutrophils can lead to severe tissue damage in diseases characterized by chronic inflammation. Indeed, in rheumatoid arthritis (RA), activated PMN contribute to tissue damage by releasing a number of destructive agents. On the other hand, chronic activation of PMN could prevent opportunistic infections present in immunosuppressed patients. This project addresses the isolation and mechanism of action of synovial liquid components on the survival of neutrophils based on previous work (Lagraoui, 1999). Following tangential flow filtration (MW cut off: 30 and 50 kDa), concentrated CM enhanced the viability (75%) of 24-hour cultured human neutrophils isolated from peripheral blood of healthy volunteers (39% ± 9.5 vs 68% ± 2.5, p<0.01) as seen in Lagraoui (1999) previous work. N-terminal protein sequence analysis of the concentrated CM and fractionated conditioned media from previous work revealed 2 known proteins contained in both analysis: albumin, and fetuin. In view of the importance of neutrophiles in immune defense, we compared the benefits of albumin and fetuin to those of granulocytes macrophages-colony stimulating factor (GM-CSF), a growth factor used as an adjunct to cancer chemotherapy. Albumin and fetuin were tested by the AnnexinV-FITC/7-AAD method and displayed an inhibition of neutrophil apoptosis of two to three folds relative to control value. Moreover, albumin (A : 200μM) and fetuin (F : 200μM) rescue human PMN from mutamycin-induced apoptosis, comparable to GM-CSF (GM : 10ng/ml); (Ctrl : 43% ± 10; A : 74% ± 3; F : (82% ± 6 et GM : 74% ± 7; p<0.01). Albumin also induces cellular signaling pathways activation via PI3-K and ERK, whereas fetuin acts through PI3-K pathway only. They induce the differentiation of HSCs into erythrocytes progenitors BFU-E. In immunosuppressed mice, albumin protects white blood cells depletion induced by cytotoxic agent from spleen and blood. Considering all the benefits of albumin and fetuin, their targeting as an adjunct to cancer chemotherapy could be disappointing in view of their lack of specificity. On the other hand, their multiple benefits could have a major impact on neurodegenerative disorders and ischemic events.

Malaria, caused by the apicomplexan parasite Plasmodium, is a major cause of morbidity and mortality throughout the world. This study has focused on the role of the spleen in the control of the blood stage of infection. Three aspects have been examined specifically: the effect of infection on the architecture of the spleen, the role of the spleen in parasite clearance and the formation of B cell memory. Firstly, the effect of infection on the splenic microarchitecture was examined. An essential component of the splenic architecture is the marginal zone (MZ), an area of the spleen that separates the reticuloendothelial red pulp of the spleen from the lymphoid white pulp compartment. Two unique populations of macrophages are found in the marginal zone: marginal zone macrophages (MZM) and marginal metallophilic macrophages (MMM). In the current study, parasitised red blood cells (pRBC) as well as normal RBC located to the MZ thirty minutes after intravenous injection and formed close associations with both MMM and MZM. Eight days after infection, at the time of peak parasitemia, a complete loss of both MMM and MZM was observed. Assays to detect cell death revealed that the loss of both MMM and MZM appeared to occur as a result of apoptosis. The apoptosis was not induced by up regulation of the inflammatory cytokines tumour necrosis factor or interferon-γ and could not be blocked by over expression of the apoptosis inhibitor Bcl2. Significantly, MMM were retained in the absence of CD8+ T cells implicating CD8+ T cells in the loss of MMM. Finally, infection of CD95-/- mice demonstrated that CD95/CD95-ligand (Fas/Fas-ligand) interactions were responsible for some of the CD8+ T cell-mediated loss of MMM. These data provide evidence for a novel interaction between MMM and CD8+ T cellsfollowing infection with Plasmodium. Secondly, the role of the spleen in the control of parasitemia and disease was monitored with an emphasis on determining the role of splenic macrophage populations (MMM, MZM and red pulp macrophages [RPM]) in parasite clearance. A clodronate liposome-mediated macrophage depletion technique was used, and caused a complete loss of all three macrophage sub-populations, as well as 50% of splenic dendritic cells, within 24 hours of administration. Each of the macrophage populations, as well as splenic DC, demonstrated different repopulation kinetics following their depletion from the spleen and these kinetics were utilised to examine each cell population in isolation. RPM depleted mice had significantly higher peak parasitemias than the controls. This peak returned to the level observed in undepleted control animals only after the repopulation of RPM was complete, suggesting that RPM play a role in the control of peak parasitemia following infection. Neither MMM nor MZM played a role in the control of parasitemia. The role of non-splenic macrophages and splenic dendritic cells also was investigated and shown to be insignificant in the absence of splenic macrophages. Finally, the role of RPM in mice immune to infection was investigated and their role shown to be dispensable, with immune mice clearing parasitemia efficiently in the absence of RPM. RPM therefore are important for the innate control of infection with P. chabaudi but are dispensible once adaptive immunity is established. Finally, the role of the spleen in the development of parasite-specific B cell memory was examined. Initial studies demonstrated that germinal centre (GC) development was compromised following infection with P. chabaudi, with an involution of B cell follicles noted early in infection. Adoptive transfer of memory B cells from immunised to naïve mice demonstrated that some protection was conferred on recipient mice by parasite-specific memory B cells. But, the memory B cells could not protect the host from developing parasitemia and did not produce significant amounts of parasite-specific immunoglobulin within seven days of challenge infection. Memory B cells could not be detected ten weeks after infection, indicating that the development, or survival, of parasite-specific memory B cells was compromised. The development of bystander memory B cells was not affected by infection. Finally, long-lived plasma cells were shown to develop in response to infection, although re-exposure of the cells to parasites in the form of recrudescent parasitemia resulted in their loss. This study therefore has identified a defect in the development of long-term, B cell-mediated, protection against infection with P. chabaudi. Each of these factors has significant implications for the understanding of how the spleen contributes to the control of infection with Plasmodium and potential applications for the further development of malaria vaccines and treatment regimens.

Le dysfonctionnement de l'exocytose des granules cytotoxiques est responsable d'une susceptibilité accrue aux pathogènes intracellulaires qui s'accompagne de l'activation continue et anarchique des lymphocytes cytotoxiques et des macrophages. Ce phénomène conduit à la lymphohistiocytose hémophagocytique (HLH), un syndrome auto-inflammatoire fatal en absence d'intervention thérapeutique. Les mutations des gènes codant pour la perforine (PRF-1) ou pour certaines des protéines impliquées dans la biogénèse ou le transport vésiculaire des granules cytotoxiques sont causales des formes familiales ou primaires de la HLH (FHL). La HLH fait également partie des complications secondaires aux infections à herpesviridae et à certains désordres immunologiques importants tels que l'arthrite juvénile idiopathique (SoJIA). Au moment d'entreprendre les travaux présentés dans ce manuscrit, le premier cas de HLH induite par une mutation menant à l'activation constitutive de la composante NLRC4 de l'inflammasome était décrit. L'inflammasome est une structure multimérique composée d'un récepteur cytosolique, de la protéine échafaud ASC et de la Caspase-1. Son activation mène à la maturation des pro-formes de l'IL-1β et l'IL-18 ainsi qu'à leur sécrétion. L'activation constitutive de NLRC4 étant suffisante au déclenchement de la HLH, nous avons tenté de comprendre si cette structure y était essentielle dans le cadre des défauts génétiques de cytotoxicité. Nous avons donc invalidé la protéine ASC ou Caspase-1 dans le modèle murin de HLH déficient pour la perforine (PRF1 -/-). Nous avons également testé l'hypothèse qu'un déficit de cytotoxicité pouvait expliquer le développement de la HLH chez les patients souffrant de SoJIA. Nos résultats montrent que l'inflammasome est nécessaire à la production d'IL-18 lors de la HLH mais qu'il n'est pas essentiel au développement de la maladie dans le cadre des FHL. Par ailleurs, nous montrons que la cytotoxicité des cellules NK semble normale chez les patients atteints de SoJIA, ce qui suggère que les mécanismes immunologiques à l'origine de la HLH dans les FHL et dans les maladies autoinflammatoires comme la SoJIA sont distincts. Dans la seconde partie de ce manuscrit, nous avons étudié sur le rôle de la sérine/thréonine/tyrosine kinase Styk1 dans la régulation des lymphocytes cytotoxiques NK. Ces derniers sont responsables du contrôle immunitaire précoce des pathogènes intracellulaires et contribuent à l'immunosurveillance des cellules tumorales. Suite à leur activation, ils relâchent de très grandes quantités d'IFN-y et de TNF-α, faisant ainsi le lien entre l'immunité innée et adaptative. La reconnaissance des cellules cibles par les lymphocytes NK est gouvernée par l'expression d'un éventail de récepteurs qui transduisent des signaux, activateurs ou inhibiteurs, et dont la balance se traduit par l'activation ou la tolérance. Ces récepteurs sont codés au sein de deux complexes génétiques très denses, le complexe de cytotoxicité naturelle (NCR) et le complexe des récepteurs des leucocytes (LRC). Au moment de commencer ces travaux, nous avions révélé que l'expression de la kinase Styk1 fait partie de la signature transcriptionnelle des lymphocytes NK. Sa fonction dans le système immunitaire demeure toutefois inconnue. Néanmoins, la localisation génétique favorable de Styk1, près du NCR, ainsi que son implication dans la voie PI3K-AKT, en faisaient un candidat potentiel de régulation des lymphocytes NK. Afin de connaître le rôle de Styk1 dans le développement et les fonctions effectrices des lymphocytes NK, nous avons donc généré une souris pour laquelle Styk1 est invalidé. Nos résultats confirment que Styk1 est exprimée de façon spécifique par les cellules NK. Nous avons également détecté une diminution de l'activité constitutive de la voie AKT/mTOR dans les cellules NK, mais le développement, l'homéostasie et la fonction des cellules NK sont cependant normaux dans les souris déficientes en Styk1 / Upon recognition of infected or target cells, CD8+ T and Natural Killer (NK) lymphocytes initiate a polarized degranulation of vesicle storing cytotoxic molecules (perforin: PRF1 and granzyme B). By altering the target cell’s cellular membrane integrity, perforine allows granzyme B to translocate to its cytosol. Genetic anomalies may affect normal cytotoxic functions and severely hamper the control of intracellular pathogens. In this context, the pathogenic signal remains uninterrupted and both cytotoxic lymphocytes and macrophages are continuously stimulated. This auto-inflammatory pathological condition is named hemophagocytic lymphohistiocytosis (HLH) and is fatal without therapeutic intervention. HLH can also occur secondary to infection with viruses from the herpesviridae family, or be concomitant to important immune alterations such as systemic onset juvenile idiopathic arthritis (SoJIA), with no clear etiological cause identified. In 2014, a case of HLH mediated by the constitutive activation of the NLRC4 inflammasome receptor was first described. The inflammasome is a multimeric structure involving a cytosolic receptor, a scaffold protein – ASC – and Caspase-1. In the immune system, the inflammasome is expressed in macrophages and dendritic cells and senses pathogenic (PAMP) and danger (DAMP) associated signals. Once activated, inflammasome’s protein Caspase-1 catalyzes the maturation of pro-IL-1b and pro-IL-18 and leads to their secretion. Since NLRC4 constitutive activation appears to be sufficient for triggering HLH, we aimed to understand if the inflammasome structure was essential to the development of the syndrome. In order to address this question, we invalidated the inflammasome through the abrogation of ASC or Caspase-1 in PRF1 -/- HLH mouse model. We also tested the hypothesis that an altered cytotoxic function could explain the high prevalence of HLH in the proinflammatory context of SoJIA. The results we present here show that the inflammasome is responsible for the elevated levels of IL-18 in the serum of HLH patients. However, the inflammasome is facultative for its development. We also demonstrate that in patients suffering from SoJIA, NK cells show normal cytotoxicity, suggesting that immunological mechanisms involved in FHL and secondary HLH are distinct. In the second part of this manuscript, we aim at understanding the role of Styk1 serine/threonine/tyrosine kinase in NK cells’ regulation. NK cells are in charge of eliminating stressed, virally infected or transformed cells. Upon activation, they secrete large amounts of IFN-γ and TNF-α, thus bridging innate and adaptive immunity. Capabilities for recognition of target cells is endowed by the expression of numerous stochastically expressed activating and inhibitory receptors. The balance between activating and inhibitory signal allows for self-tolerance or activation upon engagement of abnormal cells. Activating and inhibitory receptor are germline encoded in two dense, large complexes, the Natural Killer Complex (NKC) and the Leukocyte Receptor Complex (LRC). At the moment of starting this work, we had recently identified that Styk1 was a signature transcript of NK cells. However, its function in NK cells and more generally in the immune system remains unknown. Nevertheless, its genetic localisation near the NKC and its potential implication in the PI3K-AKT pathway prompt that it may play a role in NK cell development and/or functions. In order to evaluate the role of Styk1 in NK cells’ regulation, we generated a mouse model in which its expression is abrogated. Our data confirms that amongst all immune subsets, Styk1 is specifically expressed by NK cells. Styk1 was also able to discriminate NK cells from other ILCs. In this study, we show that Styk1 invalidation lead to a decrease of activity in the AKT/mTOR pathway. However, NK cells development, homeostasis and function were surprisingly normal in Styk1 -/- mice

High frequencies of CTL recognizing laboratory strains of HIV-1 are present in HIV-1 infected adults as early as preseroconversion. The presence of HIV-1 specific CTL during primary infection has been correlated with better control of early viremia and a more delayed onset of CD4 lymphocyte loss. Previous experiments in our laboratory have demonstrated that, unlike HIV-1 infected adults, the majority of vertically infected infants lack CTL which recognize laboratory strains of HIV-1 within the first year of life. ADCC antibody responses against laboratory strains of HIV-1 env gene products are also delayed until at least two years of age. As a possible correlate, disease progression is also more rapid in vertically infected infants. We hypothesized that HIV-1-specific CTL are type-specific in early infancy and that the use of target cells expressing laboratory strain gene products might limit the detection of HIV-1-specific CTL. To address this hypothesis, HIV-1 env genes from early isolates of four infants were PCR amplified, cloned, and used to generate recombinant vaccinia vectors (vv). The frequencies of CTL precursors (CTLp) recognizing env gene products from autologous isolates and the IIIB strain of HIV-1 were measured at time points from early infancy to 19 months using limiting dilution analysis (LDA). ADCC titers were also measured against autologous and IIIB env gene products at 4 time points spanning 2 months to 2 years of age. CTL precursors from 3 of 4 of these patients were specific only for autologous HIV-1 env gene products during the first 6 to 12 months of age. A pattern of CTL responsiveness was observed in these 3 patients in which type-specific CTL precursors observed in early infancy were replaced by cross-reactive, group-specific CTL by 6 to 12 months of age. CTL precursors from a fourth patient at 12 months of age recognized IIIB env and 1 out of 2 envs derived from 2 autologous viral isolates. High titers titers of ADCC antibodies against autologous env were detected in two infants prior to the detection of ADCC antibodies to IIIB. In two other infants, group specific ADCC antibody responses were detected in late infancy. Our results demonstrate that young infants can mount HIV-1 specific CTL and ADCC responses. The ability of young infants to mount cellular immune responses to HIV-1 also provides support for the concept of perinatal vaccination to prevent HIV-1 transmission. Furthermore. the lack of broadly-reactive CTL in early infancy suggests that the use of vaccines based on laboratory strains of HIV-1 may not afford protection from vertical infection.

L'oligomérisation enzymatique de la rutine et esculine a donné lieu à cinq fractions d'oligomères de masse moléculaire moyenne entre 2127,42 et 8331,85 g/mol pour la rutine et 688,12 et 6973 g/mol pour l'esculine. L'analyse de ces fractions par FTIR montre que les fractions d'oligorutines sont obtenues à travers des liaisons C-C, C-O et C=O. Les fractions d'oligoesculines sont obtenues à travers des liaisons C-C. Une meilleure solubilité des oligorutines et des oligoesculines dans l'eau et une plus faible solubilité de ces oligomères dans l'éthanol comparé à leurs monomères a été mis en évidence. Une diminution de l'activité antiradicalaire vis-à-vis de DPPH., ABTS+. et OH. proportionnelle à la masse moléculaire moyenne des fractions d'oligorutines a été observé, contrairement aux fractions d'oligoesculines qui montrent un important pouvoir chélateur de ces mêmes radicaux comparé à leurs monomère. Une augmentation du pouvoir chélateur de fer, inhibiteur de la xanthine oxydase, réducteur du cuivre (CUPRAC), de l'activité antigénotoxique, ainsi que de l'activité stimulatrice de la prolifération des splénocytes, et des lymphocytes (B et T) proportionnelle au degré d'oligomérisation des oligomères étudiées a été noté. L'effet des fractions d'oligorutines et oligoesculines étudiées sur les macrophages en suivant la production de monoxyde d'azote (NO) montre un pouvoir anti-inflammatoire comparé à leurs monomères. L'étude de l'activité lysosomale induite par les fractions d'oligorutine révèle un pouvoir immunostimulateur proportionnelle à la masse moléculaire moyenne des oligorutines, et inversement proportionnelle à celle-ci pour les oligoesculines / Rutin and esculin have been polymerized by laccase. Five fractions with between 2127.42 and 8331.85 g/mol for oligorutins, and between 688.12 and 6973 g/mol for oligoesculins, were obtained. Fourier transformed infrared analysis showed that oligorutins were formed through C-C, C-O and C=O linkages, while oligoesculins were obtained through C-C linkages. Oligorutins and oligoesculins show a higher solubility in water and a lower solubility in ethanol compared to their monomers. The oligomerization of rutin decrease its antiradical capacity, while oligoesculin fractions demonstrated a high antiradical activity compared to monomeric esculin. Oligomer fractions showed a better iron chelating power, xanthine oxidase inhibition, copper reducing power (CUPRAC), antigenotoxic activity, and splenocytes stimulator activity compared to their monomers. Oligorutin and oligoesculin exhibited an important anti-inflammatory capacity through the nitric oxide inhibition. Moreover, oligorutin fractions demonstrated an immunostimulatory effect proportional to their degree of oligomerization, while oligoesculin fractions showed an immunostimulatory effect inversely proportional to their degree of oligomerization

A exocitose de grânulos secretórios é o principal mecanismo efetor de células TCD8+. No entanto, pouco se sabe sobre a composição dos grânulos líticos dessas células. Resultados prévios do nosso grupo identificaram algumas dezenas de novas proteínas desses grânulos. Dentre elas foi identificada Gal-1. A literatura relata que Gal-1 age por via exógena através de sua secreção por via não convencional. Dados iniciais do nosso grupo apontam um novo cenário para esta proteína no qual ela está presente em grânulos citotóxicos. Através das técnicas de microscopia eletrônica e confocal e de ensaios de citotoxicidade, nossos resultados sugerem que Gal-1 participa do papel citotóxico das CTLs modulando a via dos receptores de morte FAS-FASL. Nós também mostramos que Gal-1 interfere com o tempo de contato entre APCs e linfócitos TCD8+, com a ativação dessas células e com o controle da proliferação dos linfócitos. Nossos resultados apontam um novo cenário para Gal-1, no qual ela está presente em grânulos líticos das CTLs e está relacionada a resposta efetora dessas células. / Exocytosis of secretory granules is the main effector mechanism of CD8+ T cells. In particular, little is known about CTLs lytic granules composition. Previous results from our group identified a few dozens of new proteins associated with these granules. Among them, we identified galectin-1. Literature reports the extracellular action of Gal-1. Initial data from our group suggested a new scenario for this protein, since Gal-1 was found inside cytotoxic granules. Here, we show by transmission electron and confocal laser scanning microscopy and cytotoxicity assays that Gal-1 has a role on CTL killing probably mediating the FAS-FASL pathway. We also show that Gal-1 is regulates the time of contact between APCs and TCD8+ lymphocytes, the activation of APCs and the proliferation of CD8 T cells. Taken together, our findings suggest a new scenario, in which Gal-1 is present in CTL granules and participates in cytotoxic effector response.