An attractive strategy to improve efficacy of current Influenza A Virus (IAV) vaccines is to promote protective CD4 T cell responses. Antiviral CD4 T cell responses are predominantly classified as strong IFN-gamma producing T helper type 1 (Th1) cells. Yet, the role of IFN-gamma in protection against IAV is still unclear, suggesting absolute Th1 polarization may be expendable for effective IAV immunity. Here we test this hypothesis using models that restrict the deficiency of known transcriptional regulators of Th1 immunity in only CD4 T cells, avoiding indirect impact on other immune cell responses. We find the 'master regulator' of Th1 cells, the T-box transcription factor T-bet (Tbx21), to be dispensable for CD4 T cell-mediated protection from lethal IAV but important for maximizing the magnitude of effector responses by regulating cell trafficking to the lung. While donor Tbx21-/- responses gain Th17 characteristics, they still produce substantial IFN-gamma, suggesting their Th1 attributes may still be required for protection. Interestingly, Tbx21-/- cells expressed more Eomesodermin (Eomes), a paralog of T-bet, but Eomes-/- cells retain WT-like responses suggesting minor roles for Eomes in presence of T-bet. In contrast, Tbx21-/-Eomes-/- cells, completely lose their Th1 identity but remarkably exhibit stronger inflammation-induced Th17 attributes than Tbx21-/- cells. Strikingly, we find in vitro Th17-primed Tbx21-/-Eomes-/- effectors lose their plasticity to become Th1 but instead strengthen their Th17-ness in IAV infected mice but still protect. Finally, we observed that protection of previously primed Tbx21-/- and Tbx21-/-Eomes-/- mice from a lethal unrelated IAV strain required T cell mediated immunity. Our observations thus demonstrate novel roles for Eomes in broadening the scope of protective mechanisms against IAV. Furthermore, we decisively demonstrate protective roles for prototypical non-plastic Th17 responses in primary and secondary responses, thus increasing the scope of target mechanisms relevant for CD4 T-cell based vaccination strategies against viral pathogens.

A synthesis is described for a number of 16,16-dimethyl analogs of the prostacyclin and related 6-keto prostaglandin types. Included are l6, l6-dimethyl-PGI2 sodium salt (XLIV), 6α-l6, l6-dimethyl-PGI1(XLV), 6β-l6, l6-dimethyl-PGI1 (XLVII), 6-keto-l6, l6-dimethyl-PGF1-α (XLIX), and 6-keto-l6, l6-dimethyl PGE1 (LV). Done, but not included, is the activity for these analogs in the blood platelet aggregation inhibition assay. This activity was consistently less than for the corresponding 16, 16-dihydro compounds.

The triple antibiotic formulation, known as anti-MAP therapy, exhibits unique synergistic antimicrobial activity and should be effective for treatment of Crohn's disease (CD) associated with Mycobacterium avium subspecies paratuberculosis (MAP). The absence of MAP detection in some CD cases may be linked to poor diagnostics or lack of association with the disease. To understand the therapeutic response of some CD patients to anti-MAP therapy in absence of MAP detection, the immunomodulatory potency of anti-MAP therapy and its major ingredients, clarithromycin (CLA) and rifabutin (RIF), in THP-1, Caco-2, and Jurkat T-cells were investigated. Anti-MAP formulation at 2.0 µg/mL decreased MAP viability in macrophages by 18-fold over 72 h. Additionally, M1/M2 macrophage polarization ratio was reduced by 6.7-fold, and expression and protein levels of TNF-a and IL-6 were reduced by 2.9-fold, whereas IL-10 increased by 5.0-fold in these cells. Mechanistically, the effect of anti-MAP formulation on NF-kB activation was dose-dependent and decreased to 13.4% at 2.0 µg/mL. Anti-MAP therapy also reversed the pro-inflammatory response in lipopolysaccharide (LPS)-induced macrophages, which shows that the anti-inflammatory effect of the treatment is not just due to a decrease in MAP viability. Furthermore, this study shows that anti-MAP therapy exhibits anti-cytotoxic effects in Caco-2 monolayers infected with MAP or treated with dextran sodium sulfate (DSS). Anti-MAP therapy decreased T-cell proliferation by up to 4.8-fold following treatment with phytohemagglutinin (PHA) or MAP purified protein derivative (PPD). Overall, the data demonstrate that anti-MAP therapy plays a significant role in modulating and eliciting a protective immune response in macrophages, endothelial cells, and T lymphocytes, even in absence of infection. This may explain the therapeutic response of some CD patients to treatment, even in absence of MAP detection, infection, or total eradication. The study supports anti-MAP therapy as an alternate treatment option for CD, especially in absence of reliable MAP diagnostics.

<p><strong>Introduction</strong></p> <p>The airway epithelium, which acts as a protective barrier, is impaired in asthmatic patients and may contribute to abnormal airway function. Chronic inflammation, a feature of asthma, is associated with structural changes in the airway epithelium including the transformation of columnar epithelial cells into mucin secreting goblet cells. Human epithelial cells exposed to Interleukin-13 (IL-13) <em>in vitro</em> resulted in goblet cell metaplasia and a significant drop in transepithelial resistance, indicating that barrier function is impaired.</p> <p><strong>Aim</strong></p> <p>We sought to determine whether goblet cell metaplasia alone is sufficient to impair airway epithelial barrier function <em>in vivo</em>.</p> <p><strong>Methods</strong></p> <p>Female BALB/c mice were infected with an adenovirus to overexpress IL-13, a control adenovirus, or no virus. Barrier integrity was assessed via single-photon emission computed tomography (SPECT) imaging by measuring the dispersion of technetium-labeled diethylene triamine pentaacetic acid (^99mTc-DTPA) out of the lungs over time. Lung sections were stained by Periodic acid-Schiff to detect the presence of mucin-containing goblet cells.</p> <p><strong>Results</strong></p> <p>IL-13 exposure resulted in goblet cell metaplasia and associated airway hyperresponsiveness to methacholine. However, there was no significant increase in dispersion of ^99mTc-DTPA over time from the airways in IL-13 overexpressed mice compared to control mice.</p> <p><strong>Conclusion</strong></p> <p>IL-13 induced goblet cell metaplasia did not impair the airway epithelial barrier to ^99mTc-DTPA in our <em>in vivo</em> mouse model. Therefore, we conclude that epithelial dysfunction to DTPA observed in human asthmatics and in animal models of asthma are not due to IL-13 induced goblet cell metaplasia.</p> / Master of Science (MSc)

<p>Lung cancer is the leading cause of cancer related deaths in both the US and Canada and efforts still need to be made towards understanding the disease. The role of inflammation in the promotion of cancer development represents a newer avenue of research. The glycoprotein (gp)-130 cytokine interleukin-6 (IL-6) has a well established role in promoting inflammation and recent evidence suggests roles in development of certain tumors in animal models. Less is known of the related family member oncostatin M (OSM) and the functions of either IL-6 or OSM in lung cancer development is not known. Based on the hypothesis that these cytokines promote lung cancer development, IL-6 and OSM were overexpressed in the lungs of two separate mouse models for lung cancer utilizing adenovirus vectors encoding IL-6 or OSM. The first mouse model utilized a Cre-conditional oncogene KRAS G12D (developed by Tyler Jacks) in which endotracheal administration of adenovirus (Ad)-encoded Cre-recombinase resulted in increases in lung densities in a dose-dependent fashion over a period of 6 weeks that were measurable by CT scanning and histology. Increases in cytokines IL-6 and kertinocyte chemoattractant (KC) were detectable in the bronchoalveolar lavage (BAL) by week 4, as well as marked increases in alveolar macrophage numbers. Macrophages were also shown as a possible target for Cre-mediated recombination and mutant KRAS expression. Administration of either AdIL-6 or AdOSM as well as AdCre resulted in a trend toward increases in tumor burden with AdOSM based on experiments terminated at 4 weeks. The second mouse model involved endotracheal administration of the lewis lung carcinoma (LLC) cell line, which after 7 days resulted in detectable tumor burden. Administration of either AdIL-6 or AdOSM and LLC cells simultaneously was shown to increase tumor burden relative to AdDl70 co-administration. These results suggest a possible role of IL-6 or OSM in promoting lung tumor development in animal models and may ultimately reveal gp130 cytokines IL-6 or OSM as a possible therapeutic target for the treatment of lung cancer.</p> / Master of Science (MSc)

<p>Class A scavenger receptors are multifunctional transmembrane glycoproteins that mediate macrophage functions like phagocytosis and endocytosis. The macrophage receptor with collagenous structure (MARCO) is one such receptor. It has been shown that the extracellular cysteine-rich domain of MARCO is responsible for ligand binding, but the role of the cytoplasmic domain in ligand uptake is unclear. The aim of the studies presented in this thesis is to characterize the role of the cytoplasmic domain of MARCO and to characterize the molecular pathway of MARCO-mediated endocytosis.</p> <p>Full-length human MARCO (hMARCO) and Δ1-34hMARCO, which lacks the first thirty-four amino acids were created in order to determine whether amino acids 1-34 contained residues required for receptor internalization and surface expression. The constructs were stably expressed in HEK293T cells and found to have similar levels of surface expression and same rate of internalization without ligand. Interestingly, hMARCO, but not Δ1-34hMARCO, surface expression was up-regulated upon ligand incubation.</p> <p>In order to ascertain the importance of clathrin, dynamin and actin in MARCO-mediated endocytosis, specific endocytic inhibitors were used. MARCO-mediated ligand uptake was inhibited when clathrin and actin polymerization and, dynamin functions were impaired by these inhibitors. Furthermore, ligand uptake by Δ1-34hMARCO-expressing HEK293T was insensitive to inhibitors of clthrin and dynamin but not inhibitors of actin.</p> <p>In conclusion, MARCO mediates endocytosis via a clathrin-mediated, dynamin-dependent pathway that involves actin. Amino acids 1-34, are required clathrin and dynamin but not actin functions during MARCO-mediated endocytosis. Additionally, amino acids 1-34 might also be important for MARCO recycling but not receptor internalization or surface expression.</p> / Master of Science (MSc)

<p><strong>Rationale: </strong>Lung-homing of bone marrow (BM)-derived progenitor cells is associated with inflammatory and remodeling changes in asthma. Stromal cell derived factor-1α (SDF-1α) is a potent progenitor cell chemoattractant and its local production in the lung promotes lung homing of progenitor cells. The role of pro-inflammatory cytokines in promoting traffic of progenitor cells to the site of inflammation in asthma has not been investigated. The TH2 cytokines, interleukin (IL)-4 and IL-13, are key regulators of asthma pathology.</p> <p><strong>Objective: </strong>To investigate the role of IL-4 and IL-13 in modulating the trans-migrational responses of hemopoietic progenitor cells (HPC).</p> <p><strong>Methods: </strong>HPC were isolated from cord blood (CB) and peripheral blood (PB) and migrational and adhesive responses were assessed using transwell migration assays and adhesion to fibronectin-coated wells, respectively. Responding cells were enumerated by flow cytometry.</p> <p><strong>Results: </strong>IL-4 and IL-13 had no direct effect on progenitor cell migration. Pre-incubation with each of these cytokines primed SDF-1α stimulated migration of CB and PB-derived HPC (CD34+45+ cells) but not eosinophil-lineage committed progenitors (CD34+45+IL- 5Rα+ cells) or mature eosinophils to SDF-1α. For HPC, priming effects of IL-4 (0.1ng/ml) and IL-13 (0.1ng/ml) were detectable within 1hr and optimal at 18hr post- incubation and IL-4 was the more effective priming agent. Disruption of lipid rafts inhibited IL-4 priming of SDF-1α stimulated migration of HPC indicating that increased incorporation of CXCR4 into membrane lipid rafts mediates the cytokine primed migrational response of HPC. This was confirmed by confocal fluorescent microscopy.</p> <p><strong>Conclusions: </strong>IL-4 and IL-13 prime the migrational response of HPC to SDF-1α by enhancing the incorporation of CXCR4 into lipid rafts. The priming effect of these cytokines is specific to primitive HPC. These data suggest that increased local production of IL-4 and IL-13 within the lungs may promote increased SDF-1α mediated homing of BM-derived HPC to the airways in asthma.</p> / Master of Science in Medical Sciences (MSMS)

<p>Various studies have shown an association between neutrophilic airway inflammation and severe asthma, but have failed to establish a causal relationship. In these studies airway neutrophilia could be due to high steroid doses, an airway infection, an epiphenomenon of severe asthma or a combination of these. We have examined the role of neutrophils in severe asthma in patients on optimum steroid doses with controlled eosinophilic airway inflammation and chemotactic activity of IL-17 as one potential mechanism of neutrophil recruitment to the airway.</p> <p>We examined the number, viability and activity of neutrophils in blood and sputum of three groups of asthma subjects divided on the basis of asthma severity. We also compared direct migration of blood neutrophils towards IL-17 between non-asthmatics and severe asthma subjects.</p> <p>Viability and survival at 24 hours was measured by examining apoptotic and non-apoptotic cells. Activation was examined by measuring the production of hydrogen peroxide and the expression of primary and secondary granule proteins. In migration study, migration of neutrophils towards IL-17 was measured.</p> <p>Blood neutrophils were increased in severe asthma subjects as compared to moderate and mild asthma subjects. There was no difference in sputum neutrophil numbers. There was no difference in viability, although blood neutrophil 24 hour survival was increased in severe asthma subjects as compared to moderate asthma subjects. There was no difference in the level of activation amongst the three groups.</p> <p>IL-17 was not a chemotactic stimulus for neutrophils. The study results show that sputum neutrophil numbers and activation are not increased in severe asthma as compared to less severe asthma. Therefore, the study results do not support a causal relationship between airway neutrophilia and severe asthma.</p> <p>Airway neutrophilia observed in previous studies might be due to airway infections or high doses of steroids taken by study subjects.</p> / Master of Health Sciences (MSc)

<p>Atherosclerosis is a disease affecting the blood vessels that is inflammatory in nature, and plays an important role in cardiovascular disease (CVD), one of the leading causes of morbidity and mortality worldwide. Oncostatin M (OSM), a member of the IL-6/gp130 cytokine family, has been implicated in atherosclerosis both in mouse models and in humans. OSM synergizes with other stimuli in various systems to regulate cells. Infectious pathogens as well as danger associated host molecules stimulate members of the innate immune system, including Toll-like Receptors (TLRs), to respond in a pro-inflammatory manner to cause cell activation and cytokine release. Experiments were performed to determine whether OSM and LPS (a TLR-4 ligand) synergize in regulation of vascular wall cells <em>in vitro</em>.</p> <p>Upon stimulation of Aortic Adventitial Fibroblasts from mice (MAAFs) and humans (HAoAFs) as well as Human Aortic Smooth Muscle Cells (HAoSMCs) with LPS in combination with OSM, it was determined that there was a synergistic increase in IL-6 and VEGF levels in the cell supernatants as measured by ELISA compared to either treatment alone. MAAFs were also able to synergistically express KC upon stimulation with LPS and OSM, while in HAoAFs and HAoSMCs, LPS induced IL-8 levels were supressed by OSM. These effects were unique to OSM among gp130 cytokine members, as treatment of these cells with LPS in combination with LIF, IL-6, IL-31, or IL-11 had no marked effects compared to LPS alone. Furthermore, MCP-1 steady state mRNA levels were elevated 6 hours post stimulation with LPS and OSM compared to either treatment alone in HAoAFs and HAoSMCs.</p> <p>While OSM did not appear to modulate TLR-4 expression, OSM treatment resulted in an increased phosphorylation signal in STAT-1,-3, and -5, as well as Akt in MAAFs and HAoAFs. In addition, combined LPS and OSM stimulation resulted in an increased phosphorylation signal of the MAPK p38 compared to either treatment alone. Furthermore, a neutralizing antibody to the OSMr-β was able to inhibit HAoAF IL-6 responses to PBMC conditioned medium. Together, these findings indicate that OSM and LPS can synergize <em>in vitro </em>to induce the expression of inflammatory factors in vascular wall cells, emphasizing the potential role of OSM, TLR-4 ligands, and adventitial fibroblasts in vascular inflammation.</p> / Master of Science (MSc)

<p>Allergic asthma is a chronic and complex disease of the airways characterized by dysregulated immune-inflammatory responses to aeroallergens and reversible airflow obstruction. The prevalence and economic burden of allergic asthma have increased substantially over the last five decades. Despite remarkable progress in our understanding of the immunobiology and pathophysiology of asthma, the ontogeny of the disease remains elusive. As a result, there is a lack of effective preventative strategies. Here, we used a murine model of allergic asthma to house dust mite (HDM), the most pervasive indoor aeroallergen worldwide to address issues pertaining to the development of allergic asthma. First, we provided a comprehensive computational view of the impact of dose and length of HDM exposure on both local and systemic allergic outcomes (Chapter 2). Parameters, such as thresholds of responsiveness, and non-linear relationships between allergen exposure, allergic sensitization and airway inflammation were identified. We, then, investigated molecular signatures implicated in the onset of allergic responses (Chapter 3). HDM exposure was associated with production of the epithelial-associated cytokines TSLP, IL-25 and IL-33. However, only IL-33 signaling was necessary for intact Th2 immunity to HDM, likely because of its superior ability to induce the critical co-stimulatory molecule OX40L on dendritic cells and expand innate lymphoid cells. Lastly, as individuals are most likely exposed to allergens concomitantly to other environmental immunogenic agents, we studied the impact of an initial immune perturbation on allergic responses to sub-threshold amounts of HDM (Chapter 4). We showed that transient expression of GM-CSF in the airway substantially lowers the threshold of allergen required to generate robust, HDM-specific Th2 immunity, likely through increasing IL-33 production from alveolar type II cells. These studies favor a paradigm whereby distinct molecular pathways can elicit type 2 immunity, intimating the need to classify asthma into distinct clinical subsets.</p> / Doctor of Philosophy (PhD)