Airway hyperresponsiveness (AHR) is one of the primary features of allergic airways disease. Despite continuous allergen exposure atopic asthmatics do not develop progressively worsening AHR. The mechanism(s) that limit AHR are unknown. Two valid candidates are regulatory T cells (Treg) and antigen presenting cells (APC). Dendritic cells (DC) are the main APC within the airways. Presentation of allergens to T cells can result in the differentiation and expansion of different subsets of T cells including effector Treg cells. The precise role of Treg and DC in the attenuation of allergen-induced AHR remains unknown. The general aim of this thesis is to investigate mechanisms to limit AHR in a murine model of atopic asthma. Specific aims are to: 1. develop a murine model of allergen-induced attenuation of AHR, 2. determine the potential role of regulatory T cells (Treg) in allergen-induced AHR attenuation, and 3. determine the potential role of airway dendritic cells (DC) in allergen-induced AHR attenuation. Balb/c mice were sensitised with intraperitoneal Ovalbumin (OVA) in aluminium hydroxide and challenged with a single, 3-weeks or 6-weeks of OVA aerosols. Aerosols were 1% OVA in sterile saline delivered for 30 minutes for three days per week. Animals were sacrificed 24 hours after the final aerosol for measurements of lung function and Methacholine (MCh) responsiveness (low-frequency forced oscillation technique), collection of bronchoalveolar lavage fluid (BALF) and serum. '...' In contrast, 6-weeks of OVA challenges decreased Treg numbers back to control levels. Adoptive transfer of 1x106 Treg taken from DLN of 3-week challenged mice attenuated AHR in single-OVA recipients (p<0.05). Furthermore, in vivo depletion of Treg in 3-week OVA challenged mice restored AHR (p<0.05 compared with control). Similar proportions of CD4+ T cells became activated following both aerosol regimes, however total numbers of airway CD4+ T cells were decreased (p<0.05), and OVA-specific CD4+ T cell proliferation in DLN was reduced (p<0.05) after 3-weeks versus one OVA aerosol. Analysis of antigen handling by airway APC populations showed antigen uptake (OVA-647) and processing (DQ-OVA) by macrophages and airway DC subsets to be down-regulated (p<0.05) after 3-weeks of OVA aerosols. In addition, adoptive transfer of Treg into single-OVA recipients did not affect antigen handling by airway APC populations. These data suggest that Treg are responsible for allergen-induced attenuation of AHR in vivo in established airways disease. AHR attenuation was associated with an altered function of airway DC, resulting in reduced antigen capture and processing, leading to limited clonal expansion of antigen-specific CD4+ T cells with limited production of Th2 cytokines. Furthermore, Treg were not directly responsible for the down-regulation of allergen capture in the airways. In conclusion, knowledge of the role of Treg and DC in attenuation of AHR could potentially result in improved and more directed therapies for the attenuation of AHR in atopic asthmatics.

In the post smallpox era, vaccinia virus (VACV) has emerged as an important candidate vaccine vector. As yet, the binding receptors and entry mechanisms utilised by the two infectious forms, IMV and EEV, in dendritic cells (DCs) are unknown. We have investigated the interactions between VACV and C-type lectin receptors (CLRs) that are known to be utilised by many other viruses for binding and entry in DCs. Using a variety of CLR ligands and inhibitors we were unable to inhibit IMV or EEV binding to MDDCs and we conclude that they do not bind to CLRs. We have also investigated VACV entry in MDDCs and show that both IMV and EEV enter MDDCs via an endocytic pathway. Using a variety of drugs that inhibit cellular processes we found IMV and EEV entry to be actin- and calcium-dependent. EEV entry was also cholesterol- and energy-dependent, whereas IMV entry was only partially dependent on these factors. Both IMV and EEV colocalised with endolysosomal markers. This data suggests that EEV may enter DCs via caveolin-mediated endocytosis whereas IMV entry can occur via multiple complementary mechanisms, including endocytosis and fusion. Macropinocytosis may also constitute a minor route of entry for IMV as entry was partially inhibited by dimethyl amiloride and the virus colocalised with dextran. Finally we have provided a comprehensive flow cytometric analysis of Toll-like receptor (TLR) expression at the protein level in MDDCs and monocyte-derived Langerhans cells (MDLCs) as models for different myeloid DC subsets. We found TLR expression to be cell type-specific and MDDCs expressed the full repertoire of TLRs 1-9, including small amounts of TLR8 and TLR9 on the cell surface. The expression of these TLRs that recognise nucleic acids on the surface of cells may constitute an early warning system for signalling the presence of viral invaders that would normally subvert the function of DCs. We also found TLR expression in mature cells to be dependent on the nature of the maturation stimulus (lipopolysaccharide versus cytokine/prostaglandin cocktail) and VACV infection induced profound down-regulation of all TLRs. These findings will have important implications for the rational design of VACV-vectored vaccines.

[Truncated abstract] The cornea plays a major role in the refraction of light and thus the maintenance of its transparency is critical for optimal vision. Infection or trauma can initiate a host inflammatory response, which can cause edema of the collagenous stroma. This tissue edema compromises vision by disrupting the regular arrangement of the corneal stromal lamellae, whose organization is critical to its refractive properties. Until recently, it was the accepted dogma that the cornea was an immune privileged tissue owing in part to its avascular nature and paucity of resident macrophages and dendritic cells (DCs) in the central region of the cornea. However, recent studies have identified heterogenous populations of macrophages and DCs in both the corneal stroma and epithelium. Despite the recognition of the existence of these cells in the cornea, very little is known about their biological role. The overall purpose of the experiments described in this thesis is to characterise corneal macrophages and DCs in homeostatic conditions and investigate their role in the initiation of inflammatory responses to bacterial ligands that induce corneal inflammation and contribute to the severity and resolution of bacterial keratitis. Experiments described in this thesis utilized a range of transgenic, knock-out and bone marrow (BM) chimeric mice to address the immunological function and characterization of BM-derived cells in the mouse cornea. Of particular importance was the use of Cx3cr1 transgenic mice, which contain an enhanced green fluorescent protein (eGFP) encoding cassette knocked into the Cx3cr1 gene that disrupts its expression but facilitates GFP expression under the control of the Cx3cr1 promoter. ... This highlights a novel functional role for corneal BM-derived cells in the recognition and initiation of inflammatory responses to LPS. Finally, a novel observation of a potential mechanism by which DC in the cornea communicate with neighbouring DCs via fine membrane extensions was identified in both chimeric and wild-type mice. These membrane nanotubes, found exclusively on MHC class II+ cells in the corneal stroma, significantly increased in density in the central cornea under inflammatory conditions, suggesting a role for these cell protrusions in the immune response. These data represent the first ever description of nanotubes in vivo, the only previous evidence of their presence being in vitro studies. In summary, the data presented in this thesis supports a role for Cx3cr1 in the homing of DCs to the normal corneal epithelium and also suggests that Cx3cr1-deficiency may influence the ability of corneal macrophages and DCs to respond to bacteria. In addition, the thesis supports a role for resident corneal macrophages and DCs in the initiation of immune responses following challenge with LPS, which is possibly supported by a newly discovered system of membrane nanotubes. A greater understanding of the biology of the resident corneal immune cells could lead to the development of potential therapies aimed at targeting macrophages and DCs as a means of regulating potentially harmful inflammatory responses in the cornea.

Gene therapy has emerged as a field to modulate cell functions by introducing genes of interest to target cells. An emerging focus in this field is to employ non-viral vectors to deliver immunosuppressive cytokines to dendritic cells (DCs) to attenuate damaging immune responses. DCs serve as potential targets for suppression of T cell responses. In this work, we investigated the ability of polycation-modified polymeric particles complexed with interleukin-10 (IL-10) gene to modulate DCs. The delivery systems (designated as PSO10H6 and PLGAO10H6) were formed by coating cationic peptide O10H6 (O: ornithine; H: histidine) on the polystyrene (PS) and poly (lactic-co-glycolic acid) (PLGA) particulates. A mouse IL-10 encoding plasmid (pIL-10) was loaded on the surface of PSO10H6 and PLGAO10H6 via ionic interactions. Physical characterization of these particles revealed stable colloidal dispersions (diameters: 297.2&#177;14nm in PLGAO10H6-pIL-10 and 126.0&#177;8nm in PSO10H6-pIL-10). DNA molecules carried by PSO10H6 and PLGAO10H6 were protected from serum digestion. Results from in vitro gene transfection studies showed two-fold enhancement of IL-10 expression in bone marrow-derived DCs transfected with PSO10H6-pIL-10 and PLGAO10H6-pIL-10 compared to untransfected DCs. Their suppressive functions were evaluated in an in vitro mixed lymphocyte model. Results indicated that PSO10H6-pIL-10 and PLGAO10H6-pIL-10 modified DCs elicited weakest proliferation of allogeneic bulk T cells as well as CD4 and CD8 T cells among all the delivery modes. Using cell-embedded Matrigel as a surrogate graft, we showed that IL-10 gene-modified DCs suppressed host cell infiltration in vivo. These data suggested PSO10H6-pIL-10 and PLGAO10H6-pIL-10 deliver an overriding suppressive signal to T cells. Further studies revealed T cells stimulated by the IL-10 gene-modified DCs exhibited characteristics of regulatory T (Treg) cells, as evident by up-regulation of a Treg cell marker forkhead-type transcription factor 3 (Foxp3). This result was concomitant with an increase in of transforming growth factor beta (TGF-beta) production. &lt;br&gt;Taken together, this work demonstrated that PSO10H6 and PLGAO10H6 are effective in delivering pIL-10 to modulate DCs to suppress T cell responses. Collectively, the results raise the prospects of using PSO10H6 and PLGAO10H6 as vectors to deliver immunosuppressive genes to modulate T cell responses in vivo. / Mylan School of Pharmacy and the Graduate School of Pharmaceutical Sciences / Pharmaceutics / PhD / Dissertation

Cancer vaccines have shown little success in clinic. Dendritic cells (DCs) are of particular interest in cancer vaccination due to their role in cell-mediated immunity. Active targeting of DCs, through PLGA nanoparticles (PLGA-NPs) decorated with ligands for DC-expressed mannose receptor (MR) can enhance internalization, processing and presentation of antigens and subsequent immnuostimulation. In this study we have shown PLGA-NPs decorated with mannan and the synthetic hydrophobized mannan, especially those with covalent attachment, can target DCs leading to increased uptake of nanoparticles and DC maturation. This approach may be used for improved delivery of antigens and adjuvants to DCs and development of more efficient cancer vaccines. Moreover, significant progress in cancer vaccination requires immunomonitoring. Live imaging using a Positron Emission Tomography (PET) probe encapsulated in PLGA-NPs can elucidate dynamics of recruitment and fate of DCs to develop successful vaccines. The PET-nanoprobe prepared by radio-iodinated 5-IDFPdR demonstrated uncontrolled high burst release implying low quality images. / Pharmaceutical Sciences

Résumé Dendritic cells (DCs) are professional APCs that have a unique capacity to initiate primary immune responses, including tolerogenic responses. We have genetically engineered bone marrow-derived DCs to express the immunosuppressive cytokine IL-10 and tested the ability of these cells to control experimental asthma. A single intratracheal injection of OVA-pulsed IL-10-transduced DCs (OVA-IL-10-DCs) to naive mice prior to OVA sensitization and challenge prevented all the cardinal features of airway allergy, namely eosinophilic airway inflammation, airway hyperreactivity, and production of mucus, Ag-specific Igs and IL-4. OVA-IL-10-DCs also reversed established experimental asthma and had long-lasting and Ag-specific effects. We furthermore showed, by using IL-10-deficient mice, that host IL-10 is required for mediating the immunomodulatory effects of OVA-IL-10-DCs and demonstrated a significant increase in the percentage of OVA-specific CD4+CD25+Foxp3+IL-10+ regulatory T cells in the mediastinal lymph nodes (MLNs) of OVA-IL-10-DC-injected mice. Finally, adoptive transfer of CD4+ MLN T cells from mice injected with OVA-IL-10-DCs protected OVA-sensitized recipients from airway eosinophilia upon OVA provocation. Our study describes a promising strategy to induce long-lasting Ag-specific tolerance in airway allergy./L’asthme atteint des proportions épidémiques dans les pays développés et a un impact négatif sur la qualité de vie. De plus les coûts des soins de santé relatifs à cette maladie ne cessent d’augmenter. La nette augmentation de l’incidence durant ces dernières décennies reste une énigme, les facteurs environnementaux ayant probablement contribués pour une large part dans ce processus. Bien que le traitement actuel de l’asthme avec des corticostéroïdes inhalés et des agonistes β2 à longue durée d’action est satisfaisant et sans danger, des inquiétudes restent sur les effets à long terme des corticostéroïdes, en particulier lorsqu’on voit que les traitements commencent parfois très tôt dans l’enfance. De plus, la thérapie actuelle ne semble pas inhiber le TGF-β ni les dépôts de collagène, importants dans le remodelage des voies aériennes qui, au final, contribue à augmenter l’HRB des voies respiratoires. La prévalence et la sévérité de l’asthme atopique augmentent de façon alarmante partout dans le monde depuis ces vingt dernières années {Eder, 2006 #2}. Les traits pathophysiologiques de l’asthme allergique, à savoir l’éosinophilie pulmonaire chronique, l’hyperréactivité bronchique des voies aériennes (HRB) à une variété de stimuli non spécifiques, la production excessive de mucus dans les voies aériennes et les niveaux élevés d’IgE dans le sérum, sont tous étroitement liés à une réponse immune de type Th2 aberrante envers des antigènes habituellement inhalés (Ag) {Busse, 2001 #466; Larche, 2003 #467; Ray, 1999 #465; Wills-Karp, 1999 #464}. Les lymphocytes Th2 spécifiques de l’antigène exercent des fonctions effectrices cruciales en produisant un répertoire propre de cytokines, les plus importantes d’entre-elles étant l’IL-4, l’IL-5 et l’IL-13 {Busse, 2001 #466; Larche, 2003 #467; Ray, 1999 #465; Wills-Karp, 1999 #464}. Essentiellement, l’asthme atopique est la manifestation d’une réponse immune Th2 aberrante envers un aéroallergène inoffensif. La condition requise pour développer une réponse immune Th2 est la participation de cellules présentatrices d’antigènes pour les réponses primaires et secondaires à un allergène. Les CDs sont les principales cellules pour activer et différencier les lymphocytes T CD4+ naïfs en sous-groupes distincts. De plus, la délétion des CDs durant la réponse immune primaire et secondaire de l’inflammation allergique des voies respiratoires dans les modèles animaux ont montré que ces cellules devaient absolument être présente au cours de ces deux phases. Les cellules dendritiques (CDs) sont des cellules présentatrices d’antigène professionnelles qui ont la capacité unique d’initier les réponses immunes primaires, incluant les réponses tolérogéniques. Nous avons génétiquement généré des CDs dérivés de cellules de la moëlle osseuse capables d’exprimer une cytokine immunosuppressive, l’IL-10. Nous avons testé leur capacité à contrôler un asthme expéritalement induit. Une simple injection par voie intra-trachéale de CDs transduites avec des lentivirus porteurs du gène codant l’IL-10 et chargées avec la protéine OVA (OVA-IL-10-DCs) à des souris naïves avant de les sensibiliser à l’OVA et de les provoquer à l’OVA prévient tous les traits caractéristiques de l’alargie des voies respiratoires, à savoir l’inflammation éosinophiliques des voies aériennes, l’hyperréactivité bronchique et la production de mucus, d’immunoglobulines spécifiques de l’antigène et d’IL-4. Les cellules OVA-IL-10-DCs réversent ausi l’asthme exprimental établi et ont des effets spécifiques de l’antigène, et ce, à long terme. Nous avons ensuite montré, en utilisant des souris déficientes pour l’IL-10, que l’IL-10 produit par l’hôte est nécessaire pour contrôler les effets immunomodulateurs des cellules OVA-IL-10-DCs. De plus, nous avons enfin une augmentation significative du pourcentage des lymphocytes T régulateurs CD4+CD25+Foxp3+IL-10+ spécifiques de l’OVA dans les ganglions médiastinaux (MLNs) des souris injectées avec les cellules OVA-IL-10-DC. Enfin, le transfert adoptif des lymphocytes CD4+ isolés des cellules de ganglions médiastinaux de souris injectées avec les cellules OVA-IL-10-DCs protège les souris receveuses, préalablement sensibilisées à l’OVA, d’une éosinophilie des voies aériennes suite à une provocation à l’OVA. Notre étude décrit une stratégie prometteuse pour induire une tolérance spécifique de l’antigène à long terme dans le cadre d’une allergie des voies aériennes.

La toxine de pertussis (PTX) est une A-B protéine considérée comme l’un des principaux facteurs de virulence de Bordetella pertussis, l’agent bactérien responsable de la coqueluche. Aujourd’hui, cette maladie représente encore un réel danger pour les nouveaux-nés et les nourrissons non ou partiellement immunisés. Actuellement, la coqueluche provoque encore la mort d’environ 350.000 individus par an. La toxicité de la PTX est liée à l’activité enzymatique de sa sous-unité A capable d’inhiber les voies de signalisation associées aux protéines Gi. La partie B, quant à elle, permet l’entrée de cette sous-unité A dans le cytoplasme des cellules cibles en se liant spécifiquement à son ou ses récepteurs membranaires toujours inconnus de nos jours. Des études réalisées chez la souris et chez l’homme ont montré que les vaccins anticoquelucheux combinés à différents antigènes vaccinaux étaient capables de moduler leurs réponses humorales spécifiques. Par ailleurs, la PTX est couramment qualifiée d’agent immunostimulant. En effet, des modèles murins de vaccination permirent d’identifier des propriétés adjuvantes de la PTX coadministrée avec des antigènes non relevants. Le travail développé dans ce manuscrit étudie les effets de la PTX sur 2 types cellulaires primordiaux sollicités lors d’une vaccination : la cellule dendritique (DC) et le lymphocyte T CD4+ naïf. Les DC sont les seules cellules présentatrices d’antigènes aptes à initier une réponse immune primaire. Dans un premier temps, nous avons montré que la PTX était capable d’activer des DC générées in vitro à partir de monocytes. En effet, elles acquièrent un phénotype mature caractérisé par une augmentation de l’expression membranaire des molécules costimulatrices et du CMH de classe II, démontrant un effet direct et spécifique de la PTX sur les DC myéloïdes. Parallèlement, ces DC produisent du TNF-a, de l’IL-12p40 et de l’IL-12p70 et activent NF-kappaB, un facteur de transcription essentiel au processus de maturation. Nous avons obtenu des résultats similaires avec une toxine génétiquement modifiée qui est enzymatiquement inactive. A partir de sang total incubé avec la PTX, nous avons par ailleurs observé que les DC circulantes du nouveau-né étaient déficientes dans leur maturation et leur sécrétion d’IL-12p70 comparées aux DC de l’adulte. D’autre part, il a été décrit précédemment que la PTX exerçait des effets mitogènes sur les lymphocytes T humains et murins. Cependant, le rôle qu’elle joue sur la population des lymphocytes T CD4 naïfs reste peu connu. A l’issue de notre second travail, nous pouvons dès lors affirmer que la PTX est également capable d’activer des lymphocytes T CD4+CD45RA+ naïfs isolés à partir des cellules mononuclées du sang périphérique, et ce indépendamment de son activité enzymatique. En effet, ces lymphocytes T CD4+ naïfs stimulés par la PTX prolifèrent, synthétisent des quantités non négligeables d'ARN messagers codant pour l’IL-2 et le TNF-a, augmentent l’expression membranaire des molécules CD40L, CD69 et CD25 et expriment la protéine Foxp3. Cette activation s’accompagne de la translocation nucléaire de NF-kappaB et NFAT. Parallèlement à l’adulte, la PTX active les lymphocytes T CD4 néonataux. Néanmoins, ceux-ci prolifèrent moins bien et expriment plus faiblement le CD40L à leur surface. Enfin, la PTX induit la sécrétion de taux importants d’IFN-g par des T CD4+CD45RA+ naïfs adultes mis en présence de DC autologues. Nous terminerons en proposant l’hypothèse suivante : La PTX pourrait exercer ses propriétés adjuvantes par l’intermédiaire de différents mécanismes comprenant notamment la maturation des DC d’origine myéloïde et l’activation des lymphocytes T CD4+CD45RA+ naïfs. Ces 2 populations cellulaires sont en effet les principaux protagonistes impliqués dans la réponse immune primaire.

Efficient removal of apoptotic cells is critical for development, tissue remodelling, maintenance of homeostasis, and response to injury. Phagocytosis of apoptotic cells is mediated by many phagocytic receptors, soluble bridging molecules, and pro-phagocytic ligands on the surface of apoptotic cells. Macrophage phagocytosis in general is controlled by stimulatory and inhibitory mechanisms. An example of the latter mechanism is that mediated by the cell surface glycoprotein CD47, which by binding to the inhibitory receptor Signal Regulatory Protein alpha (SIRPα) on macrophages, is known to inhibit phagocytosis of viable host cells. The studies of the present thesis aimed at investigating possible changes to CD47 on apoptotic cells, which could influence their elimination by macrophages. The endoplasmatic protein calreticulin (CRT), in conjunction with Low density lipoprotein Receptorrelated Protein 1 (LRP1) on the phagocyte, can act as a receptor for collectin family members and mediate uptake of apoptotic cells. However, CRT itself was found to also be expressed on the surface of many viable cell types, and the CRT expression increased on apoptotic cells. By using antibodies to LRP1 or receptor‐associated protein (RAP), an antagonist blocking LRP1 ligand binding, we found that CRT on target cells could interact in trans with LRP1 on a phagocyte and stimulate phagocytosis. CD47 on the target cell inhibited LRP1‐mediated phagocytosis of viable cells (e.g. lymphocytes or erythtocytes), but not that of apoptotic cells. The inability of CD47 on apoptotic cells to inhibit LRP1‐ mediated phagocytosis could be explained in two ways: 1) Some apoptotic cell types (fibroblasts and neutrophils, but not Jurkat T cells) lost CD47 from the cell surface, or 2) CD47 is evenly distributed on the surface of viable cells, while it was redistributed into patches on apoptotic cells, segregated away from areas of the plasma membrane where the pro‐phagocytic ligands CRT and phoaphatidylserine (PS) were concentrated. Apoptotic murine thymocytes also showed a patched distribution of CD47, but no significant loss of the receptor. However, both PS‐independent and PS‐dependent macrophage phagocytosis of apoptotic CD47‐/‐ thymocytes was less efficient than uptake of apoptotic wild‐type (wt) thymocytes. This contradictory finding was explained by the fact that CD47 on apoptotic thymocytes did no longer inhibit phagocytosis, but rather mediated binding of the apoptotic cell to the macrophage. These effects could in part be dependent on the apoptotic cell type, since uptake of experimentally senescent PS+ wt or CD47‐/‐ erythrocytes by macrophage in vitro, or by dendritic cells (DC) in vivo, were the same. In vivo, PS+ erythrocytes were predominantly trapped by marginal zone macrophages and by CD8+ CD207+ DCs in the splenic marginal zone. DCs which had taken up PS+ erythrocytes showed a slight increase in expression levels of CD40, CD86 and MHC class II. These findings suggest that PS+ erythrocytes may be recognized by splenic macrophages and DCs in ways similar to that reported for apoptotic T cells. Uptake of senescent erythrocytes by DCs may serve as an important mechanism to maintain self‐tolerance to erythrocyte antigens, and defects in this function may facilitate development of AIHA. Glucocorticoids are used to treat inflammatory conditions and can enhance macrophage uptake of apoptotic cells. We found that the glucocorticoid dexamethasone time‐ and dose‐dependently stimulated macrophage cell surface LRP1 expression. Dexamethasone‐stimulated macrophages also showed enhanced phagocytosis of apoptotic thymocytes and unopsonized viable CD47‐/‐ erythrocytes. In summary, LRP1 can mediate phagocytosis of both viable and apoptotic cells by binding CRT on the target cell. Macrophage expression of LRP1 is increased by glucocorticoids, which could be one explanation for the anti‐inflammatory role of glucocorticoids. While CD47 on viable cells efficiently inhibits phagocytosis in macrophages, CD47 on apoptotic cells does not and can sometimes even promote their removal.

The work presented herein focuses on the activation of the adaptive immune system in order to develop T cell-based immunotherapy for viral infections and cancer. The main goal was to identify and activate viral or tumoral antigen-specific T cells by using different identification, isolation and stimulation techniques. One such approach was that we modified dendritic cells (DCs) with an adenoviral vector encoding the full length pp65 antigen from cytomegalovirus (CMV). Through strategic modification techniques we demonstrate that it is possible to obtain DCs presenting antigen-specific peptides both on major histocompatibility complex (MHC) class I and MHC class II molecules for simultaneous CD8+ and CD4+ T cell activation. We also demonstrate that it is possible to generate prostate antigen-specific CD8+ T cells from a naïve repertoire of T cells by using DCs and HLA-A2-restricted peptides derived from prostate tumor-associated antigens or by using an adenoviral vector encoding the full length prostate tumor-associated antigen STEAP. We further demonstrate that CD8+ T cells directed against several prostate-specific peptide epitopes can be found in peripheral blood and in the prostate tumor area of prostate cancer patients. Furthermore, we have characterized a number of prostate-derived cell lines in terms of HLA haplotype and tumor-association antigen expression. We concluded that our methods for generating T cells restricted to CMV antigen have the ability to be applied for adoptive T cell transfer to patients with CMV disease and that prostate antigen-specific T cells can be found within prostate cancer patients, which enables future development of immunotherapeutic strategies for prostate cancer.

Dendritic cells (DCs) are prime mediators of innate and adaptive immunity. In humans the DC population comprise only 0.1% of all leukocytes, making their isolation and ex vivo manipulation difficult. Since study of DC activity in vitro requires large numbers of DCs to be readily available, a cell line model, KG-1, was selected. KG-1 cells are a cytokine-responsive human CD34+ myelomonocytic cell line and can be induced to differentiate to a DC phenotype. A range of differentiation agents and protocols were compared, and differentiation efficiency was determined using both morphological features and cell surface marker expression. Expression of CD83, CD11c, CD123, CD86, HLA-DR and DC-SIGN was assessed by immunofluorescence and flow cytometry. KG-1 cells stimulated with 10 ng/ml PMA and 100 ng/ml Ionomycin were found to be the ideal model for obtaining Dendritic Like Cells (DLCs) in vitro. The effect of lactic acid bacteria on KG-1 differentiation was also tested using two immunomodulatory strains, Lactobacillus rhamnosus R0011 and Lactobacillus helveticus R0052. After 5 days of incubation with R0011 the KG-1 cells expressed DC-specific surface markers CD83, CD86, CD11c, CD123, DC-SIGN and HLA-DR. Lactobacillus rhamnosus R0011 induced a marked rise in CD83 expression with a mean fluorescence intensity of 115.3 after 5 days, suggesting this strain promoted KG-1 differentiation to DLC. Analysis of cytokine by KG-1 DLC indicated that constitutive production of pro-inflammatory cytokines TNF-α and IL-12 was minimal. However IL-10 and TGF-β were detected after TLR-agonist stimulation of R0011-differentiated KG-1s. This study aimed to develop and assess the KG-1 cell model for screening effects of mediators and microbes on DC. / UOIT