O presente estudo avaliou a ocorrência de imunoparalisia e sua associação com pior prognóstico em pacientes pediátricos internados em uma UTI de hospital terciário. Para determinar a presença de imunoparalisia procedeu-se a dosagem da expressão de mHLA-DR usando o QuantiBRITE TM Anti HLA-DR/ Anti- Monocyte, um novo reagente que padroniza os valores da citometria de fluxo para o mHLA-DR. Determinamos a expressão de mHLA-DR em 30 pacientes com sepse grave ou choque sépticos admitidos na UTI Pediátrica no período do estudo, mHLA-DR foi quantificado por duas vezes: entre os dias 3 a 5 (mHLA-DR1) e 5 a 7 (mHLA-DR2) após o inicio do quadro séptico. Também foi calculado o deltamHLA-DR (mHLA-DR2 - mHLA-DR1). Dosamos, ainda, o mHLA-DR em vinte e um controles hígidos. O objetivo do estudo foi determinar se a expressão de mHLA-DR correlaciona-se com a mortalidade em pacientes sépticos pediátricos. Os resultados mostram que o mHLA-DR foi significativamente menor nos pacientes sépticos do que nos controles (p = 0.0001). A mortalidade foi de 46% nos pacientes com valores negativos ou < 1000 mAb/cell de deltaHLA-DR, e 7% em pacientes com valores positivos ou > 1000 mAb/cell de deltaHLADR. O deltamHLA-DR médio foi significativamente diferente entre sobreviventes e pacientes que foram a óbito (p = 0.023). Dessa forma, após a análise estatística dos resultados concluímos que o deltaHLA-DR correlaciona-se com a mortalidade em pacientes pediátricos com sepse grave e choque séptico / This study analysis the presence of Immunoparalysis and its association with prognosis in pediatric septic patients of a Tertiary Intensive Care Unit. To determine the presence of immunoparalysis we performed the mHLA-DR dosage using the QuantiBRITE TM Anti HLA-DR/ Anti- Monocyte, a novel reagent that standardizes flow cytometry values. We determined mHLA-DR expression in 30 patients with severe sepsis or septic shock admitted to PICU, mHLA-DR expression was quantified between days 3-5 and 5-7 after the onset of sepsis and calculated the deltamHLA-DR (mHLA-DR2 - mHLADR1). We also measured mHLA-DR levels in twenty-one healthy patients. The objective of this study was to determine if mHLA-DR values correlate with mortality in pediatric septic patients. The results showed that the mean mHLA-DR expression was significantly lower in septic patients compared with controls (p = 0.0001). Mortality was 46% in patients with negative deltaHLA-DR or < 1000 mAb/cell and 7% in patients with positive deltaHLA-DR or > 1000 mAb/cell. Mean deltamHLA-DR levels were significantly different between survivors and non-survivors (p = 0.023). After statistical analysis we concluded that deltaHLA-DR correlates with mortality in pediatric patients with septic shock or severe sepsis

O presente estudo avaliou a ocorrência de imunoparalisia e sua associação com pior prognóstico em pacientes pediátricos internados em uma UTI de hospital terciário. Para determinar a presença de imunoparalisia procedeu-se a dosagem da expressão de mHLA-DR usando o QuantiBRITE TM Anti HLA-DR/ Anti- Monocyte, um novo reagente que padroniza os valores da citometria de fluxo para o mHLA-DR. Determinamos a expressão de mHLA-DR em 30 pacientes com sepse grave ou choque sépticos admitidos na UTI Pediátrica no período do estudo, mHLA-DR foi quantificado por duas vezes: entre os dias 3 a 5 (mHLA-DR1) e 5 a 7 (mHLA-DR2) após o inicio do quadro séptico. Também foi calculado o deltamHLA-DR (mHLA-DR2 - mHLA-DR1). Dosamos, ainda, o mHLA-DR em vinte e um controles hígidos. O objetivo do estudo foi determinar se a expressão de mHLA-DR correlaciona-se com a mortalidade em pacientes sépticos pediátricos. Os resultados mostram que o mHLA-DR foi significativamente menor nos pacientes sépticos do que nos controles (p = 0.0001). A mortalidade foi de 46% nos pacientes com valores negativos ou < 1000 mAb/cell de deltaHLA-DR, e 7% em pacientes com valores positivos ou > 1000 mAb/cell de deltaHLADR. O deltamHLA-DR médio foi significativamente diferente entre sobreviventes e pacientes que foram a óbito (p = 0.023). Dessa forma, após a análise estatística dos resultados concluímos que o deltaHLA-DR correlaciona-se com a mortalidade em pacientes pediátricos com sepse grave e choque séptico / This study analysis the presence of Immunoparalysis and its association with prognosis in pediatric septic patients of a Tertiary Intensive Care Unit. To determine the presence of immunoparalysis we performed the mHLA-DR dosage using the QuantiBRITE TM Anti HLA-DR/ Anti- Monocyte, a novel reagent that standardizes flow cytometry values. We determined mHLA-DR expression in 30 patients with severe sepsis or septic shock admitted to PICU, mHLA-DR expression was quantified between days 3-5 and 5-7 after the onset of sepsis and calculated the deltamHLA-DR (mHLA-DR2 - mHLADR1). We also measured mHLA-DR levels in twenty-one healthy patients. The objective of this study was to determine if mHLA-DR values correlate with mortality in pediatric septic patients. The results showed that the mean mHLA-DR expression was significantly lower in septic patients compared with controls (p = 0.0001). Mortality was 46% in patients with negative deltaHLA-DR or < 1000 mAb/cell and 7% in patients with positive deltaHLA-DR or > 1000 mAb/cell. Mean deltamHLA-DR levels were significantly different between survivors and non-survivors (p = 0.023). After statistical analysis we concluded that deltaHLA-DR correlates with mortality in pediatric patients with septic shock or severe sepsis

Μέχρι σήμερα δεν υπάρχει εμβόλιο για καμιά μορφή των λεϊσμανιάσεων και τα φάρμακα που χρησιμοποιούνται δεν είναι ασφαλή, αποτελεσματικά και οικονομικά προσιτά. Υπάρχει άφθονη επιστημονική πληροφορία για τα αντιλεϊσμανιακά φάρμακα που χρησιμοποιούνται με αναγνωρισμένα μειονεκτήματα όπως η τοξικότητα, η ανάπτυξη αντοχής, η υποχρεωτική παραμονή στο νοσοκομείο και το υψηλό κόστος. Επιπλέον η συλλοίμωξη με τον ιό του AIDS (HIV/VL) έχει σοβαρές επιπτώσεις στην επιδημιολογία, τη διάγνωση και την πρόγνωση της νόσου. Είναι προφανές ότι η εκδήλωση της σπλαγχνικής λεϊσμανίασης είναι “ευκαιριακή” όπως αποδεικνύεται από τα στοιχεία του Π.Ο.Υ., σύμφωνα με τα οποία οι ασθενείς με AIDS έχουν 3.000 φορές υψηλότερη συχνότητα VL σε σύγκριση με τον γενικό πληθυσμό. Για τα διάφορα είδη του γένους Leishmania υπάρχουν αξιόλογα ευρήματα από παρασιτολογικές, βιοχημικές, μοριακές και ανοσολογικές μελέτες, όμως τα θεραπευτικά πρωτόκολλα ενάντια των διαφορετικών κλινικών μορφών δεν είναι ικανοποιητικά. Γεγονός αποτελεί η αδήριτη ανάγκη για την ανάπτυξη νέων θεραπευτικών προσεγγίσεων κατά των λεϊσμανιάσεων που μαστίζουν έως και 1,7 εκατομμύρια ανθρώπους σε όλη την γη. Σήμερα το ενδιαφέρον για φυσικά προϊόντα βρίσκεται σε επικαιρότητα κυρίως με την αναζήτηση νέων χημικών ενώσεων αλλά και την επανεξέταση παλαιοτέρων σε σύγχρονα πλέον πειραματικά πρωτόκολλα. Μεταξύ αυτών των προϊόντων η ελαιοευρωπεΐνη, που προέρχεται από το δένδρο της ελιάς (Olea europaea), χαρακτηρίζεται από αντιοξειδωτική, αντιμικροβιακή και αντιφλεγμονώδη δράση. Η βιοφαινόλη αυτή φαίνεται να συμβάλλει επίσης στην μακροζωία αλλά και όταν χορηγείται σε πειραματόζωα με καρκινικούς όγκους είναι ικανή στο να τους συρρικνώνει ή ακόμη και να τους εξαφανίζει. Ο σκοπός αυτής της διατριβής είναι η διερεύνηση φυσικών προϊόντων προερχόμενων από τα φύλλα και τους καρπούς του δέντρου της ελιάς αλλά και από πάρα-προϊόντα του όπως τα υγρά απόβλητα ελαιοτριβείου. Επίσης εξετάσθηκαν δύο αδρά εκχυλίσματα από τον ερυθρό οίνο ποικιλίας ξινόμαυρο. Αμφότερες οι πηγές των εκχυλισμάτων αποτελούν θεμελιώδεις λίθους της Μεσογειακής διατροφής και οι βιβλιογραφικές αναφορές τα καθιστούν ως υποσχόμενους αντιλεϊσμανιακούς παράγοντες. Τα αποτελέσματά έδειξαν ότι τα δύο καθαρά φυσικά προϊόντα που εξετάσθηκαν, η υδροξυτυροσόλη και η ελαιοευρωπεΐνη επέδειξαν επιλεκτική και σημαντική αντιλεϊσμανιακή δραστικότητα εναντίον τριών ειδών πρωτοζώων του γένους Leishmania και συγκεκριμένα των L. infantum, L. donovani και L. major. Η διατριβή εστιάστηκε στη ελαιοευρωπεΐνη και αναδείχθηκε η ικανότητά της να προκαλεί ρυθμιζόμενο κυτταρικό θάνατο αποδεικνυόμενο από μορφολογικές αλλαγές σε προμαστιγότες L. donovani, λογαριθμικής φάσης ανάπτυξης, με τη χρήση συνεστιακής μικροσκοπίας. Η στρογγυλοποίηση των προμαστιγοτών, η συμπύκνωση της χρωματίνης καθώς και η έκθεση της φωσφατιδυλοσερίνης στην εξωτερική επιφάνεια της κυτταροπλασματικής μεμβράνης με τη χρήση κυτταρομετρίας ροής είναι φαινοτυπικά χαρακτηριστικά της επαγωγής ρυθμιζόμενου παρασιτικού θανάτου που αποδείχθηκε ότι ο μηχανισμός πρόκλησής του είναι ανεξάρτητος της παραγωγής ROS. Επιπλέον η ελαιοευρωπεΐνη προκάλεσε μια καθυστέρηση στο φυσιολογικό κυτταρικό κύκλο του παρασίτου οδηγώντας στον κατακερματισμό του DNA. Η αντιλεϊσμανιακή δράση της ελαιοευρωπεΐνης αποδείχτηκε και εναντίον των αμαστιγωτικών μορφών του είδους L. donovani που είχαν in vitro παρασιτήσει σε μακροφάγα της κυτταρικής σειράς J774Α.1. Αυτή η δράση συνοδεύτηκε από μία ενδομακροφαγική αύξηση ROS ενώ η in vitro χορήγηση ελαιοευρωπεΐνης σε μυελοειδή DCs αύξησε τον πληθυσμό που παράγει IL-12 δίχως να προκαλεί παράλληλη ωρίμανσή τους. Τα ανωτέρω οδήγησαν στη μελέτη της δράσης της ελαιοευρωπεΐνης σε in vivo πειραματικό μοντέλο σπλαχνικής λεϊσμανίασης. Σε L. donovani μολυσμένα BALB/c ποντίκια χορηγήθηκε ενδοπεριτοναϊκώς ελαιοευρωπεΐνη κάθε δεύτερη ημέρα για 28 συνεχόμενες ημέρες σε τρεις διαφορετικές δόσεις (45, 15 και 5mg/kg σωματικού βάρους). Βρέθηκε ότι και οι τρεις δόσεις περιόρισαν το παρασιτικό φορτίο του σπλήνα και του ήπατος στις 3 ημέρες και στις 6 εβδομάδες μετά το πέρας της χορήγησης της ελαιοευρωπεΐνης. Διαπιστώθηκε ότι τα πειραματόζωα που έλαβαν ελαιοευρωπεΐνη και περιόρισαν την ενδοκυτταρική εξάπλωση του παρασίτου στο σπλήνα και στο ήπαρ ανέπτυξαν μια ενισχυμένη ΤΗ1 τύπου ανοσολογική απόκριση με χαρακτηριστικό ισοτυπικό προφίλ αντισωμάτων IgG2α/IgG1 και μεταγραφικών παραγόντων Tbx21/GATA-3. Η υπερ-έκφραση των IL-12p40, IFNγ, TNFα και iNOS επιβεβαιώνει την πόλωση προς τον ΤΗ1 υποτύπο ανοσολογικής απόκρισης, ενώ η έκφραση των κυτταροκινών ρυθμιστές της TΗ2 ανοσολογικής απάντησης δεν είχαν καμία αυξητική τάση. Αυτό το φαινόμενο που προέρχεται αρχικώς από την ικανότητα της ελαιοευρωπεΐνης να διατηρεί χαμηλά τα επίπεδα της προφλεγμονώδους κυτταροκίνης IL-1β, επιτρέπει τον ανοσολογικό μηχανισμό του ξενιστή να ενεργοποιηθεί (μεταγραφή του Tbx21) αποτρέποντας την είσοδο του ξενιστή σε κατάσταση χρόνιας φλεγμονικής διεργασίας που ευνοεί τον παρασιτικό πολλαπλασιασμό. Απεναντίας ενεργοποιούνται μηχανισμοί παραγωγής των μικροβιοκτόνων μορίων ROS και NO• στο σπλήνα και στο ήπαρ. Η παραγωγή των ROS σε σπληνοκύτταρα ποντικών μολυσμένων με L. donovani ήταν δοσοεξαρτώμενη ενώ αντιθέτως η παραγωγή των ΝΟ• ήταν μη-δοσοεξαρτώμενη τόσο σε κύτταρα του σπλήνα όσο και του ήπατος. Αυτή η παραγωγή των ΝΟ• φαίνεται να επιδρά στην επιβίωση των παρασίτων χωρίς να αλλοιώνει τη φυσιολογική λειτουργία των σπληνοκυττάρων και των ηπατοκυττάρων εφ’ όσον τα μόρια γλουταθειόνης στα κύτταρα του ξενιστή ήταν επαρκή για να συντηρούν τη συνεχή επιβίωση του κυττάρου ξενιστή όπως παρατηρήθηκε με την μη-ενεργοποίηση του NF-kB. Επίσης η ελαιοευρωπεΐνη επιλεκτικά ρυθμίζει την γονιδιακή έκφραση των ενζύμων που σχηματίζουν τη γλουταθειόνη και την τρυπανοθειόνη εις βάρος των αντιοξειδωτικών αμυντικών μηχανισμών του παρασίτου. Συμπερασματικά, το σύνολο των αποτελεσμάτων που περιεγράφηκαν στη διδακτορική αυτή διατριβή, προτείνουν ότι η ελαιοευρωπεΐνη δρα ως ένα αντιλεϊσμανιακό φάρμακο με ανοσοτροποποιητικές ιδιότητες. Η διερεύνηση της συνδυαστικής δράσης κλασσικών αντιλεϊσμανιακών φαρμάκων με ασφαλή, μη-τοξικά και “φθηνά” φυσικά προϊόντα όπως η ελαιοευρωπεΐνη, παραμένει μια υποσχόμενη μελλοντική προοπτική. Επιπροσθέτως, ενδιαφέρουσα θα ήταν η διερεύνηση της δράσης της ελαιοευρωπεΐνης στην έκφραση έτερων γονιδίων που κωδικοποιούν αντιοξειδωτικά ένζυμα καθώς και στους κυτταρικούς πληθυσμούς που εμπλέκονται επίσης σε in vivo πειραματικό μοντέλο σπλαχνικής λεϊσμανίασης όπως τα δενδριτικά κύτταρα, τα κύτταρα φυσικοί φονιάδες και τα CD8+. Τέλος η ελαιοευρωπεΐνη μπορεί να δοκιμασθεί σε HIV/L. donovani πειραματικό πρωτόκολλο αφού η ελαιοευρωπεΐνη είναι ικανή στο να σταματάει τον πολλαπλασιασμό του ιού HIV. / Up to now there has been neither a vaccine against any form of leishmaniasis found nor drugs that are safe, effective and inexpensive. Plethora of recent data has showed that the existing antileishmanial drugs have numerous disadvantages such as toxicity, development of resistance, long hospitalization and high cost. In addition, HIV/VL coinfection has important epidemiological, clinical, diagnostic and prognostic implications. The two diseases are mutually reinforcing. Clearly the opportunistic manifestation of VL is demonstrated by the WHO records showing that 50-75% new VL cases in South Europe concern HIV patients that bring the incidences of VL 3,000 times more frequent than in the general population. Despite the advances in the parasitological, biochemical, molecular and immunological research using various Leishmania species, the treatment protocols applied against the different forms of the disease are not satisfactory. There is an unconquerable need for the development of new therapeutic treatments to combat leishmaniasis. Nowadays, the interest concerning plant natural products is certainly undergoing a renaissance. The remarkable chemical diversity present in natural products and the accumulated research data produced so far, demonstrate their significant effectiveness against parasitic diseases suggesting the hypothesis to be tested also against leishmaniasis. This was particularly evident in the case of natural products of the olive tree (Olea europaea). Among them oleuropein has most of olive oil’s antioxidant, anti-inflammatory, and disease-fighting characteristics and it is the biophenol that provides life extending benefits. In addition to its antimicrobial and antioxidant activity, when oleuropein was given to animals with tumors, the tumors completely regressed or in some cases even disappeared. The aim of this thesis is to investigate natural products obtained from the olive tree leaves, products and their by-products (olive mill waste waters) and red wine (xinomavro variety), major cornerstones of the Mediterranean diet, as natural sources for promising antileishmanial drugs in accordance with the considerations outlined above. Our results showed that both pure constituents, hydroxytyrosol and oleuropein, exhibited the highest and the most selectively significant leishmanicidal activity against parasites of three Leishmania species, L. infantum, L. donovani and L. major, among the natural products tested. We focused on oleuropein and we discovered that it was capable of causing substantial morphological alterations upon L. donovani logarithmic promastigotes depicted with confocal microscopy namely, cell rounding up, cellular volume reduction and chromatin condensation that were accompanied with phosphatidylserine exposure to the outer leaflet of the plasma membrane. Moreover, oleuropein was found responsible for a delay on normal L. donovani cell cycle progression which was extended up to DNA fragmentation. This regulated parasitic cell death induced by oleuropein appeared to be ROS-independent. Oleuropein’s leishmanicidal capacity was also evident against the amastigote form of the parasite using an in vitro experimental model based on J774.A1 macrophages infected with L. donovani. This activity is accompanied by an increase of inracellular ROS production and the ability of oleuropein to increase the percentage of IL-12 producing myeloid DCs when is administrated in vitro. This data suggested testing the leishmanicidal activity of oleuropein upon in vivo murine visceral model. Intraperitoneal administration of oleuropein every other day for 28 days in L. donovani infected BALB/c mice, led to the dramatic reduction of the parasite load in spleen and liver. Interestingly, oleuropein treated L. donovani infected BALB/c mice, switch towards a TH1 type of immune response characterized by relevant IgG2a/IgG1 isotype and Tbx21/GATA-3 transcription factor ratio. Analysis of the whole spleen tissue revealed small but significant fold changes in gene expression of TH1 versus TH2 type of cytokines between treated and non-treated L. donovani infected BALB/c mice. Particularly, the dominance of TH1 type of response was confirmed by the up regulation of IL-12p40, IFN-γ and TNF-α which triggers elevated expression of iNOS in splenocytes in oleuropein treated L. donovani infected BALB/c mice. Despite the presence of TH2 type of response, the abiding down regulation of IL-1β permits Tbx21 expression and prevents prolonged inflammatory process and thus to disease exacerbation. We also found that oleuropein promoted a dose-dependent ROS production on spleen cells from BALB/c mice infected with L. donovani while it was able to evoke a dose-independent NO production on spleen and liver cells. NO production seems to affect parasitic viability but did not alter physiological function of spleen and liver cells since glutathione cell reservoir is capable of maintaining the continuity of host cell survival confirmed by the absence of NF-kB2 expression increase. Furthermore, oleuropein selectively regulates the transcription of glutathione and trypanothione gene which encode their synthesis enzymes at expense of parasitic antioxidant defense mechanism. The overall conclusion of the research described in this thesis suggests that oleuropein acts as an effective antileishmanial drug with demonstrable immunostimulating properties and selectively induces parasitic death by microbicidal molecules. The option of testing the combining effects of classical antileishmanial drugs with safe, non-toxic and cost effective natural products like oleuropein remains a promising future perspective. Moreover, interesting remains the effect of oleuropein upon other antioxidant genes and cell populations that play crucial roles in the in vivo experimental visceral leishmaniasis such as mDCs, NK and CD8+ cells. Finally, oleuropein could be used upon HIV/L. donovani experimental protocol since oleuropein is also capable to cease viral multiplication.

La réaction du greffon contre l’hôte (GvH) est responsable d’un grand taux de morbidité et de mortalité chez les patients recevant des greffes de cellules souches (GCSH) allogéniques. Dans ce contexte, les cellules T régulatrices sont largement étudiées et semblent avoir un grand potentiel d’utilisation dans le domaine de la thérapie cellulaire de la GvH. Parmi les populations cellulaires T régulatrices, les lymphocytes T CD4-CD8- TCRαβ+ « Doubles-Négatifs » (DN), qui ne représentent que 1-3% des lymphocytes T, ont été décrits. Ces cellules ont des propriétés inhibitrices de la réponse immunitaire qui s’avèrent spécifiques aux antigènes auxquels elles ont préalablement été exposées. La répression de la réponse immunitaire par les cellules T DN régulatrices semble être un mécanisme important impliqué dans l’induction de la tolérance aux allo-antigènes. De plus, ces cellules confèrent une tolérance immunitaire dans des modèles de greffes allogéniques et xénogéniques. En effet, ces cellules ont la capacité d’inhiber la réaction contre un allo-antigène auquel elles ont été exposées, sans inhiber la réaction contre un allo-antigène inconnu. Les cellules T DN ont été isolées et caractérisées chez l’homme où elles ont la capacité d’interagir avec des cellules présentatrices d’antigènes (APCs) par un contact cellulaire, comme chez la souris. Cependant, leur capacité immunomodulatrice reste inconnue chez l’humain. Notre objectif consistait donc principalement à étudier le rôle et le mécanisme d’action des cellules T DN régulatrices humaines in vitro, en étudiant leur capacité à inhiber une réaction lymphocytaire mixte (MLR). Nous avons montré que les cellules T DN stimulées par un allo-antigène donné inhibent des cellules syngéniques effectrices dirigées contre ce même alloantigène mais n’inhibent pas des cellules syngéniques effectrices dirigées contre un autre alloantigène, démontrant ainsi la spécificité aux antigènes de ces cellules. De plus, les T DN non stimulées par un allo-antigène n’ont pas de rôle inhibiteur. Cependant, durant cette inhibition, nous n’observons pas de modulation de l’expression des marqueurs d’activation et d’induction de l’apoptose. Afin d’étudier le mécanisme d’action des cellules T DN, nous avons mesuré l’expression intracellulaire de la granzyme B. Les résultats démontrent que les cellules T DN stimulées expriment un niveau significativement plus élevé de granzyme B que les cellules T DN non-stimulées par l’allo-antigène. Ceci suggère que l’immunosuppression induite par les cellules T DN stimulées pourrait passer par la voie granzyme B. Le mécanisme utilisé par ces cellules reste à être confirmé par nos futures expériences. / Graft-versus-Host Disease (GvHD) is a major cause of morbidity and mortality in patients receiving an allogeneic Hematopoietic Stem Cell Transplantation (HSCT). Many regulatory T cell populations have been studied and shown to have immunosuppressive properties in GvHD. Among these populations, Double Negative CD4-CD8-TCRαβ+ regulatory T cells (DN T) have been described. These cells represent 1-3% of all T cell lymphocytes and are known to have antigen-specific inhibitory functions of the immune response. The suppression of an immune response by DN T cells seems to be an important mechanism involved in the induction of tolerance to allo-antigens. Moreover, these cells also confer immune tolerance in models of allogeneic and xenogenic grafts. DN T cells have the ability to suppress syngeneic T CD4+ and T CD8+ cells in an antigen-specific manner. Therefore, these DN T cells can inhibit the reaction caused by syngeneic effector cells against a specific alloantigen to which they have been previously exposed. However, they cannot inhibit a reaction directed against an unknown alloantigen. Human DN T cells have been isolated and characterized as cells that have the capacity to interact with APCs by cell-to-cell contact, just like in mice. However, their immunomodulatory properties are still unknown in humans. The goal of our project was to study the role and immunomodulatory functions of human DN T cells in Mixed Lymphocyte Reactions (MLR). The MLRs have allowed us to demonstrate that DN T cells, after having been stimulated by an allo-antigen, have an antigen-specific inhibitory function towards the syngeneic effector cells reacting against the same alloantigen that they have been exposed to. Interestingly, they do not inhibit the reaction of these effector cells against an unknown alloantigen. However, stimulated DN T cells did not modulate the expression of the activation markers expressed by the effector cells and did not give a death signal to these cells either. Moreover, we also wanted to study how DN T cells have an immunosuppressive activity. Therefore, we compared the expression of Granzyme B in stimulated versus non-stimulated cells. Our results suggest that DN T cells may use the Granzyme B pathway to immunosuppress the effector cells. In conclusion, our results demonstrate that DN T cells have an antigen-specific inhibitory function. The mechanism used by these DN T cells remains to be confirmed with our future experiments.

A natureza sempre constituiu uma fonte extremamente rica de compostos e substâncias utilizados pelo homem para diferentes fins, principalmente na área médica, pois os produtos naturais abrangem uma variedade de agentes terapêuticos para diversas doenças, como moléstias infecciosas, câncer, desordens lipídicas e imunológicas. Com a necessidade de se encontrar novos fármacos, tanto para doenças bem definidas, quanto para novas doenças, a pesquisa de substâncias com atividades biológicas torna-se fundamental. Fontes exóticas como o ambiente marinho e, recentemente o universo dos micro-organismos, ganharam grande interesse no meio científico devido ao fato de terem sido pouco conhecidas e exploradas. Nesse contexto, o objetivo desse estudo foi avaliar se diferentes frações da macroalga marinha Bostrychia tenella e extratos de micro-organismos endofíticos isolados dessa mesma espécie possuíam atividade imunomoduladora sobre o sistema complemento (SC) humano, que é reconhecido como um dos maiores efetores do processo inflamatório. Iniciado por três vias distintas (clássica, alternativa e das lectinas), ele leva à formação de produtos de clivagem e complexos de ativação que exercem diferentes funções biológicas importantes, como quimiotaxia, ativação de fagócitos, desgranulação de mastócitos, citólise, ativação celular e apoptose. Sendo assim, este sistema desempenha papel importante em várias reações inflamatórias, bem como em diferentes mecanismos patogênicos de dano tecidual. Através do ensaio de atividade hemolítica, 10 das 20 amostras iniciais foram selecionadas por modularem esta atividade do SC no pool de soro humano normal (SHN). As 10 amostras (dentre frações, subfrações e extratos de B. tenella e seus micro-organismos endofíticos) foram capazes de induzir a geração de fragmentos de C3, componente central do SC, observados tanto em técnicas imunoeletroforéticas, quanto em Western blotting. Também, observou-se a formação do complexo de ataque à membrana (MAC) em ensaio imunoenzimático, indicando que houve ativação total do SC. Através dos resultados obtidos no Western blotting para fragmentos de C4 e Fator B foi possível identificar quais vias do SC são ativadas, quando correlacionados com os resultados dos ensaios hemolíticos para via clássica/das lectinas (VC/VL) e via alternativa (VA). Desse modo, foi possível concluir que as 10 amostras selecionadas possuem efeito imunomodulador sobre o SC humano por serem capazes de ativá-lo, seja pela VC/VL ou pela VA. Conclui-se, também, que o ensaio hemolítico cinético constitui uma importante ferramenta de triagem, assim como o Western blotting do SHN para detecção de fragmentos do SC. / Nature has always provided an extremely rich source of compounds and substances used by man for various purposes, mainly in the medical field because natural products include a variety of therapeutic agents for various diseases such as infectious diseases, cancer, lipid and immune disorders. With the need to find new drugs for either well defined diseases as for new ones, the search for substances with biological activities becomes essential. Exotic sources such as marine environment, and recently the world of micro-organisms have gained great interest in the scientific community due to the fact that they were little known and explored. In this context, the objective of this study was to assess whether different fractions of marine macroalgae Bostrychia tenella and extracts of endophytic micro-organisms isolated from this species possess immunomodulatory activity on the human complement system (CS), which is recognized as one of the major effectors of the inflammatory process. Started by three distinct pathways (classical, alternative and lectin), it leads to the formation of cleavage products and activation complexes which have various important biological functions such as chemotaxis, activation of phagocytes, mast cell degranulation, cytolysis, cellular activation and apoptosis. Thereby, this system plays an important role in various inflammatory reactions, as well as various pathogenic mechanisms of tissue damage. Through the hemolytic activity assays, 10 of the initial 20 samples were selected because they were able to modulate this activity of the CS in the pool of normal human serum (NHS). The 10 samples (among fractions, subfractions and extracts of B. tenella and its endophytic micro-organisms) were able to induce the generation of fragments from C3, a central component of the CS, which was observed both in immuno electrophoresis technique and Western blotting. Also, we observed the formation of the membrane attack complex (MAC) in enzyme immunoassay, indicating that there was total activation of the CS. By the results obtained in Western blotting for fragments of C4 and Factor B was possible to identify which pathways are activated in CS, when correlated with the results of hemolytic assays for the classical/lectin (VC/VL) and alternative pathway (VA). Thus, we conclude that the 10 selected samples have immunomodulatory effects in human CS because they were able to activate it either by VC/VL or VA. It follows also that the hemolytic assay by the kinetic method is an important tool for screening, as well as Western blotting of NHS to detect fragments of the CS.

L’activité anti-tumorale des cellules NK est régulée par des récepteurs de surface activateurs et inhibiteurs qui reconnaissent des ligands exprimés par les cellules cibles. Afin d’augmenter le potentiel cytotoxique des cellules NK face à des cellules cancéreuses autologues, Innate Pharma a développé des Ac bloquant les interactions entre certains récepteurs inhibiteurs de la cellule NK, les KIRs, et leurs ligands, des molécules du CMH de classe I.Dans un premier temps, nous avons mis en place un modèle tumoral d’efficacité des Ac anti-KIR dans des souris transgéniques pour l’expression d’un KIR. Ce modèle nous a permis de démontrer l’efficacité thérapeutique anti-tumorale du blocage des interactions entre les KIRs exprimés par les cellules NK et les molécules HLA exprimées par la tumeur. Ce modèle nous a également permis de tester la combinaison de l’Ac anti-KIR avec un Ac thérapeutique utilisé dans le traitement des lymphomes B non-hodgkiniens, rituximab. Utilisé en combinaison, ces deux Ac augmentent significativement la survie de souris greffées avec une lignée tumorale d’origine B humaine par rapport à chacun des deux traitements seuls.Ces données précliniques nous amènent à proposer une stratégie thérapeutique pour le traitement de tumeurs hématologiques, basée sur la combinaison d’un Ac anti-KIR avec un Ac induisant de l’ADCC afin de potentialiser la réponse anti-tumorale des cellules NK. / NK cell anti-tumoral activity is regulated by inhibitory and activating receptors interacting with target cell ligands. Innate Pharma has developed anti-KIR Abs (IPH2101 and lirilumab), directed against inhibitory NK cell receptors interacting with HLA molecules, in order to increase NK cell activity against autologous tumor cells.We have set up a preclinical model to assess anti-KIR anti-tumoral efficacy in transgenic mice expressing a KIR receptor. With this model, we have also shown the therapeutic benefit of combining lirilumab with rituximab, a therapeutic Ab mediating ADCC.These results support the rationale of combining anti-KIR Ab with Ab mediating ADCC as a therapeutic strategy for hematological malignancies.

Made available in DSpace on 2015-07-22T20:50:27Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-03-25 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Dentre os efeitos moduladores da Propionibacterium acnes (P. acnes), um de grande importância, verificado em nosso laboratório em um modelo murino de hipersensibilidade imediata à ovoalbumina (OVA), é a sua capacidade de direcionar a resposta imune para Th1 ou Th2, dependendo do esquema de tratamento dos animais. Efeito semelhante foi induzido pelo polissacarídeo solúvel extraído da bactéria (PS), porém, como apenas a sua capacidade de modular a resposta Th1 havia sido verificada, nós nos propusemos a investigar, no presente estudo, se o PS poderia também potencializar a resposta Th2. De fato, verificamos que o polissacarídeo solúvel extraído da P. acnes foi capaz de potencializar a reação de hipersensibilidade imediata na pata de camundongos, como demonstrado pelo aumento do número de eosinófilos no infiltrado inflamatório, predominância do número de esplenócitos produtores de IL-4 e aumento da produção de IgG1 anti-OVA, concomitantemente à diminuição de IgG2a, compatível com padrão Th2 de resposta. Além disso, nós também avaliamos se os efeitos de potencialização ou supressão da hipersensibilidade imediata induzidos pela P. acnes ou seu polissacarídeo estariam relacionados com diferenças no número e grau de ativação de células apresentadoras de antígenos (APCs) e linfócitos B1. Observamos que o aumento da quantidade de APCs esplênicas positivas para moléculas co-estimuladoras, TLR4 e IL-4 em animais tratados com P. acnes ou PS e a maior expressão de CD80 por linfócitos B1c peritoneais estava relacionada com exacerbação da resposta Th2. Por outro lado, o aumento do número de linfócitos B2 esplênicos TLR2+, bem como maior expressão de TLR9 intracelular por células dendríticas, e também menor número de células B1a peritoneais positivas para TLR2 e TLR9 intracelular em camundongos tratados com P. acnes ou PS, estava relacionado com supressão da reação. Quanto à síntese de citocinas, verificou-se um aumento menos pronunciado do número de APCs IL-4+ e também maior quantidade de células produtoras de IL-12 nos grupos em que a reação foi suprimida, em relação aos submetidos ao protocolo de exacerbação. In vitro, o estímulo concomitante de P. acnes e OVA em co-culturas de células dendríticas e linfócitos T aumentou a liberação de IL-5 e IL-17, em relação às culturas estimuladas apenas com OVA, e o estímulo concomitante de PS e OVA aumentou a síntese de IL-17. Já o estímulo com P. acnes ou PS, seguido do estímulo com OVA no dia seguinte, induziu uma diminuição da liberação de IL-5 e IL-17, em comparação com as culturas estimuladas apenas com OVA, sugerindo que a P. acnes e o polissacarídeo atuam diretamente sobre células apresentadoras de antígenos. / Among Propionibacterium acnes (P. acnes) immunomodulatory effects, one of great importance, verified in our laboratory in a murine model of type I hypersensitivity to ovalbumin (OVA), is its capacity to direct the immune response to Th1 or Th2, depending on the animals treatment. Similar effect was induced by the soluble polysaccharide extracted from the bacteria (PS), however, since only its capacity to modulate the Th1 response has been verified, we decided to investigate, in the present study, if PS could also potentiate the Th2 response. In fact, this compound was able to potentiate or suppress the immediate hypersensitivity reaction in mice, depending on the protocol used. Besides, we investigated, in this work, whether the number of spleen cells and peritoneal B1 lymphocytes would be different between the treatment protocols, being related to potentiation or suppression of the OVA response, and also if the activation status of antigen presenting cells (APCs) and B1 lymphocytes could interfere on reaction modulation. We verified that the higher numbers of APCs expressing co-stimulatory molecules and the higher expression levels of these molecules on cell surface are probably related to potentiation of the Th2 response to OVA induced by P. acnes or PS. The higher CD80 expression by peritoneal B1c lymphocytes is also possibly involved with OVA response exacerbation in these animals. Besides, there seems to be a correlation between higher number of APCs expressing TLR4 and exacerbation of the immediate hypersensitivity reaction in P. acnes- or PS-treated mice. Differences on TLRs expression by spleen and peritoneal B1 lymphocytes can also be related to the type I hypersensitivity modulation. Analysis of cytokines synthesis by spleen APCs confirmed the Th2 potentiation or suppression in this model. Finally, in vitro experiments using co-cultures of dendritic cells and T lymphocytes indicated that P. acnes and PS seem to perform their effects of Th2 response potentiation or suppression by direct action on antigen presenting cells. / TEDE / BV UNIFESP: Teses e dissertações

Submitted by Cristhiane Guerra (cristhiane.guerra@gmail.com) on 2017-02-03T15:37:52Z No. of bitstreams: 1 arquivototal.pdf: 4718514 bytes, checksum: 73b76bdede325ded91073c36318f98f2 (MD5) / Made available in DSpace on 2017-02-03T15:37:52Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 4718514 bytes, checksum: 73b76bdede325ded91073c36318f98f2 (MD5) Previous issue date: 2016-02-17 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / The synthetic alkaloid 2-methoxy-4-(7-methoxy-1,2,3,4- tetrahydroisoquinolin-1-yl) phenol encoded as MHTP, has a 93.45% yield and it had no genotoxic effect with low acute toxicity in preclinical analyses, with LD50 higher than 1000 mg / kg. The MHTP presented vasorelaxant and anti-inflammatory effects in acute inflammation models by orally administration. The aim of this study was to evaluate the immunomodulatory effect of MHTP, administered intranasally (in) in experimental allergic pulmonary inflammation induced by ovalbumin (OVA) by means of allergic (measurement of serum IgE) and inflammatory parameters (cell migration and production of cytokines, the fluid broncoalveolar- washed BAL, mucus production and histopathological pulmonary remodeling). Female BALB / c mice were sensitized with OVA at days 0 and 12 of the experimental protocol and on days 19 and 22 were treated via i.n. MHTP with the doses of 2.5 and 5 mg / kg or dexamethasone (2 mg/kg). After each treatment was aerosol challenged with OVA for 30 minutes daily; 24 hours after the last challenge, it was collected biological material for evaluation of allergic lung inflammation characteristic on allergic asthma. Treatment with MHTP at dose of 2.5 mg/kg decreased (p<0,05) the migration of total lymphocytes, (p<0,0001) the lymphocytes CD4+ and production of the cytokines IL-13, IL-4, IL-17 and IL-10. The dose of 5 mg/kg, in turn, decreased (p <0,05) the production of OVA-specific IgE and migration of lymphocytes CD3+; (p<0,0001) migration of leukocytes, total lymphocytes CD4+, macrophages and (p<0,001) eosinophils; (p<0,0001) the percentage of granulocytes; the production of the cytokines IL-13, IL-4, IL-17 and IL- 10. In addition, MHTP reduced inflammatory histopathological parameters such as hyperplasia and hypertrophy of goblet cells and mucus overproduction. The results infer that the immunomodulatory mechanism of MHTP is related to regulation of Th2 profile that is responsible for generating and maintaining allergic pulmonary inflammation process characteristic of allergic asthma. / O alcaloide sintético 2-methoxy-4-(7-methoxy-1,2,3,4- tetrahydroisoquinolin-1-yl) phenol, codificado como MHTP, possui rendimento de 93,45%, não apresentou efeito genotóxico com baixa toxicidade aguda pré clínica e DL50 maior que 1.000 mg/kg. O MHTP apresentou efeito vasorelaxante e antiinflamatorio em modelo de inflamação aguda, administrado por via oral. O objetivo do presente trabalho foi avaliar o efeito imunomodulador do MHTP, administrado por instilação nasal (i.n.), na inflamação pulmonar alérgica experimental induzida por ovalbumina (OVA), por meio dos parâmetros alérgico (quantificação de IgE sérica), inflamatório (migração celular, produção de citocinas, no fluido do lavado broncoalveolar- BAL) e morfológico (produção de muco e histologia pulmonar geral). Camundongos fêmeas BALB/c foram sensibilizados com OVA nos dias 0 e 12 do protocolo experimental e nos dias 19 a 22 foram tratados por via i.n. com MHTP nas doses 2,5 ou 5 mg/kg ou Dexametasona (2 mg/kg). Após cada tratamento, foi realizado os desafios por aerossol com OVA, durante 30 minutos diários; 24 horas após o último desafio, foi coletado o material biológico necessário para avaliação da inflamação pulmonar alérgica, característica da asma alérgica. O tratamento com MHTP na dose de 2,5 mg/kg diminuiu (p<0,05) a migração de linfócitos totais, (p<0,0001) linfócitos CD4+ e a produção das citocinas IL-13, IL-4, IL-17 e IL-10. A dose de 5 mg/kg, por sua vez, diminuiu (p<0,05) a produção de IgE-OVA específica e migração de linfócitos CD3+; (p<0,0001) migração de leucócitos totais, linfócitos CD4+, macrófagos e (p<0,001) eosinófilos; (p<0,0001) o percentual de granulócitos e a produção das citocinas IL-13, IL-4, IL-17 e IL-10. Além disso, MHTP reduziu os parâmetros inflamatórios histopatológicos e morfológicos e a hiperprodução de muco. Os resultados obtidos inferem que o mecanismo imunomodulador do MHTP está relacionado à regulação do perfil Th2, que é responsável por gerar e manter o processo inflamatório alérgico pulmonar, característico da asma alérgica.

Human mesenchymal stromal cells (hMSC) are adult stem or progenitor cells, which physiological role is reparation of damaged tissues. This is achieved mostly by secretion of trophic, angiopoietic and immunomodulatory factors. Beside this, hMSC have potential to differentiate in vitro into specialized cells, especially of the mesodermal lineages. Human MSC also significantly support hematopoiesis in hematopoietic niche. This knowledge raised high hopes for therapeutic use of hMSC, especially in regenerative medicine and treatment of autoimmune diseases, including graft versus host disease (GvHD). As a proof of concept served initially crude preparations of bone marrow mononuclear cells (BMMC), which contain small numbers of hMSC. In our hospital, two pilot clinical studies with BMMC were performed: study of treatment of acute myocardial infarction (negative, prematurely terminated) and study of treatment of peripheral leg arthery disease (promising results). Further research was aimed on optimalisation of hMSC cultivation method for clinical use to obtain highest possible yield and get free from animal proteins. Human MSC were traditionally cultivated in research-grade media with fetal calf serum (FCS), which can lead to immunization of patients after repeated application of hMSC. We achieved...

A saliva de insetos hematófagos possui moléculas capazes de modular o sistema imune do hospedeiro. Com base na literatura a respeito das atividades presentes na saliva de Aedes aegypti, investigamos se o EGS dessa espécie era capaz de modular a EAE. Imunizamos animais C57BL/6 com MOG35-55, e realizamos um tratamento com EGS. O tratamento com EGS diminuiu a incidência da doença e provocou um atraso no aparecimento dos sinais clínicos, além de estes serem mais brandos. Observamos que a modulação se deu na fase de indução da resposta imune, não na efetora. De fato, o EGS consegue suprimir a doença por 4 vias: 1) diminuindo a expressão de MHCII, CD80 e CD86 em células dendríticas, e diminuindo a produção de citocinas responsáveis pela indução das respostas Th1/Th17; 2) induzindo células produtoras de IL-10 in vivo; 3) induzindo apoptose em linfócitos T naive; 4) induzindo células com perfil Th2 produtoras de IL-4 e IL-5. Concluímos que o EGS é capaz de atuar na supressão dos sintomas durante o curso da EAE e na inibição do início da resposta imune. / The saliva of hematophagous insects has molecules that can modulate the host immune system. Based on the literature about activities found in Aedes aegypti saliva, we investigate if SGE of this species could modulate EAE. We have immunized C57BL/6 mice with MOG35-55, and carried out a treatment with SGE. The treatment with SGE reduced the incidence of disease and caused a delay onset of clinical signs making them softer. We have observed that modulation occured in the induction phase of immune response, not in effector phase. In fact, SGE can suppress the disease by four ways: 1) decreasing the expression of MHCII, CD80 and CD86 in dendritic cells and decreasing the production of cytokines responsible for Th1/Th17 response induction; 2) inducing cells producing IL-10 in vivo; 3) inducing apopotosis in naive T lymphocytes; 4) inducing cells Th2 producing IL-4 e IL-5. We came to the conclusion that SGE can act in supressing symptoms during the course of EAE and inhibiting the beggining of autoimmune response.