Being a Dissertation presented in fulfilment of the requirement governing the Degree of Master of Science in The School of Medicine, University of the Witwatersrand / Interleukin 1 (IL - 1) is a macrophage factor that exerts control over T cell activation. The experimental work presented in this dissertation consists of studies on IL - 1 production by monocytes which can be used as an in vitro correlate for monocyte function, as well as the effect of IL - 1 on immature T cells, that is, thymocytes. In accomplishing the studies presented in this dissertation, a two stage assay was employed. Firstly IL - 1 containing supernatants were produced by stimulated human peripheral blood adherent cells and secondly, the IL - 1 supernatants were assayed on mouse thymocyctes in which these supernatants caused mitogenesis. / IT2018

Despite the incorporation of the epidermal growth factor receptor (EGFR) inhibitor cetuximab into the clinical management of recurrent and metastatic (R/M) head and neck squamous cell carcinoma (HNSCC), only a small subset of patients responds to cetuximab, despite EGFR overexpression in virtually all of their tumors. At this time, there is a lack of validated predictive biomarkers to predict which patients will respond to cetuximab. Our previous work suggests that cetuximab activates the interleukin-1 (IL-1) pathway via tumor release of IL-1 alpha (IL-1α), although the implications of activating this pathway are unclear. The IL-1 pathway plays a central role in immune response and displays both pro-tumor and anti-tumor activities. IL-1 may promote tumor growth by upregulating the secretion of pro-inflammatory mediators involved in angiogenesis and metastasis. On the other hand, IL-1 signaling may promote antitumor immunity via enhancement of natural killer (NK)-cell mediated antibody-dependent cell-mediated cytotoxicity (ADCC) and T cell activity, which are important mechanisms of action of cetuximab. The goal of this work is to determine how modulation of the IL-1 pathway affects HNSCC tumor response to cetuximab and if IL-1 may serve as a predictive biomarker for patient response to cetuximab. Blockade of IL-1 signaling did not enhance the anti-tumor efficacy of cetuximab, while IL-1α overexpression and treatment with recombinant IL-1α and IL-1α nanoparticles increased HNSCC tumor response to cetuximab in immunodeficient and immunocompetent HNSCC mouse models. Mechanistically, these results appear to be due to activation of an anti-tumor NK and T cell-mediated immune response. Additionally, we found that both nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) and inducible nitric oxide synthase (iNOS) activity may be involved in the efficacy of IL-1-induced ADCC against cetuximab-coated HNSCC cells. Altogether, these results suggest that IL-1 signaling is necessary for HNSCC tumor response to cetuximab. Furthermore, we have shown that pre-treatment serum and tumor IL-1 ligands can predict progression-free survival of HNSCC patients treated with standard-of-care cetuximab and chemotherapy, cetuximab combined with other targeted therapies, and cetuximab monotherapy. Overall, we propose that IL-1α warrants further study as a novel therapeutic to enhance response to cetuximab and as a predictive biomarker for HNSCC response to cetuximab.

Most studies of the induction of cytokine synthesis in monocytes have employed an exogenous triggering agent such as lipopolysaccharide. However, in nonseptic inflammatory responses (e.g. rheumatoid arthritis) monocyte activation occurs as a result of T cell‐generated signals. In previous reports, we and others have demonstrated that contact‐dependent T cell‐generated signals are capable of contributing to macrophage activation. We have shown that plasma membranes from anti‐CD3 activated purified peripheral CD4+ T cells (TmA) but not from resting CD4+ cells (TmR) induce monocytes to synthesize interleukin (IL)‐1 in the absence of co‐stimulatory cytokines. Studies to determine the expression kinetics of the molecule(s) unique to activated CD4+ T cells which interact with monocytes to induce IL‐1 revealed that optimal expression occurred at 6 h post activation. This matched the previously reported kinetics of expression of CD40 ligand (CD40L) on activated peripheral T cells, implicating the CD40‐CD40L interaction as a candidate for the initiator of the IL‐1 signaling event. The ability of TmA to induce IL‐1 synthesis in resting monocytes could be markedly reduced by addition of a monoclonal anti‐CD40L antibody, 5c8. In addition, a monoclonal anti‐CD40 IgM (BL‐C4) proved dramatic in its ability to induce resting monocytes to synthesize IL‐1. In summary, these results demonstrate that the CD40‐CD40L interaction provides a critical component of CD4+ T cell contact‐dependent activation of monocyte IL‐1 synthesis.

Thesis (Ph. D.)--University of Toronto, 1999. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Toronto, 1999. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Texas at Austin, 1998. / Vita. Includes bibliographical references (leaves 174-206). Available also in a digital version from Dissertation Abstracts.

Thesis (Ph. D.)--Virginia Commonwealth University, 2009. / Prepared for: Dept. of Biochemistry. Bibliography: leaves 147-171. Also available on the Internet.

Cerebral ischaemia is characterised by an interruption in cerebral blood flow (CBF) leading to neuronal dysfunction and death. Pre-existing systemic inflammation is strongly associated with exaggerated brain injury following cerebral ischaemia with experimental studies showing that increased damage is mediated by interleukin (IL)-1 dependent pathways. The mechanisms through which systemic inflammation worsens stroke have yet to be elucidated, therefore in this thesis we sought to further determine how systemic inflammation affects outcome after acute cerebral ischaemia. The effects of acute pre-existing inflammation on cerebral perfusion and infarct volume after transient middle cerebral artery occlusion (MCAo) in rats were measured using magnetic resonance imaging (MRI). Systemic IL-1 caused a severe reduction in CBF and increase in infarct volume compared to vehicle. CBF changes were accompanied by upregulation of the vasoconstricting peptide endothelin (ET)-1. Blockade of ET-1 receptors reversed hypoperfusion, reduced ischaemic damage and improved functional outcome when assessed at 48h. Streptoccocus pneumoniae is the most common infection in patients at risk of stroke and is associated with an elevated inflammatory profile. The effect of an acute S. pneumoniae challenge on stroke outcome was assessed in mice and rats following transient MCAo. S. pneumoniae induced a systemic IL-1 response, exacerbated brain injury and increased platelet adhesion to the endothelium. Blockade of IL-1 with IL-1 receptor antagonist (IL-1Ra) and administration of glycoprotein (Gp) Ibα (to reduce platelet-endothelial interactions) reversed infection-mediated exacerbation of ischaemic injury and improved functional impairments after MCAo. Presence of chronic inflammation in the form of advanced age and obesity are associated with poorer outcomes following ischaemic stroke. The neuroprotective effects of delayed IL-1Ra on stroke outcome were assessed in aged lean and corpulent rats versus young rats at 7 days post-stroke. IL-1Ra reduced ischaemic damage, blood brain barrier (BBB) breakdown, improved functional outcomes and preserved neurogenesis in young and aged co-morbid rats at 24 hours and 7 days. Overall, these findings suggest systemic IL-1 is a common point of convergence in both acute and chronic pre-existing inflammatory disorders that are risk factors for stroke. Systemic IL-1 leads to excessive ischaemic damage through effects on the endothelium and the coagulation cascade. These results lend further support to the hypothesis that IL-1 is a potential therapeutic target in ischaemic stroke.

Neuroinflammation is a major feature of most neurodegenerative conditions, and can leadto the exacerbation of neuronal injury. Inflammatory challenges in the central nervoussystem (CNS) have been shown to activate peripheral immune cells, which subsequentlyinfiltrate into the brain. Concurrently, resident inflammatory cells in the CNS, such asmicroglia, become activated and release inflammatory mediators, including cytokines.The pro-inflammatory cytokine interleukin-1 (IL-1) is a key mediator of neuronal injury.Although two IL-1 agonists exist, IL-1α and IL-1β, the majority of research has focussedon the contribution of IL-1β to neuronal injury. Excitotoxic cell death in the rat brain,induced by striatal injection of the glutamate agonist AMPA, is exacerbated by coadministrationof recombinant IL-1β. To identify possible mediators which facilitate theexacerbation of neuronal injury by IL-1 this study investigated the early peripheral andcentral mediators of inflammation in response to AMPA + IL-1β.Neutrophil infiltration and increased neuronal activity were found to be present at 4h post-AMPA + IL-1β injection, which lead to the induction of microglial IL-1α in the ipsilateralcortex, in the absence of any IL-1β expression. To target the peripheral neutrophil responsean intervention study was performed to inhibit peripheral TNFα, which is thought tomobilise neutrophils. No significant effect of pre-treatment with etanercept, a TNFαinhibitor, was observed on neuronal injury produced in response to AMPA + IL-1β, thougha slight trend for protection was seen. To target the central IL-1α response after AMPA +IL-1β treatment an anti-IL-1α antibody was injected directly into the cerebral cortex, butthis had no effect on AMPA + IL-1β induced cell death. Therefore, using a reductionist invitro approach in organotypic slice cultures haemin, an inducer of endogenous IL-1α, wasused to investigate IL-1α mediated cell death. Haemin induced cell death was shown to beIL-1 dependent and preliminary studies using IL-1αKO mice indicated that IL-1α maypartially mediate this effect. This suggests that in the AMPA + IL-1β paradigm IL-1α is thedominant IL-1 isoform early after AMPA + IL-1β treatment, which can trigger subsequentneuronal cell death, as a result of the additive effects of neutrophil infiltration and highneuronal activity in the cortex. This study highlights the potential therapeutic value ofinhibiting IL-1α expression early following acute neuronal injury.

by Chuen Ka Yee. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 134-166). / Abstracts in English and Chinese. / ACKNOWLDEGEMENT --- p.ii / PUBLICATIONS --- p.iii-iv / ABBREVIATIONS --- p.v-viii / INDEX FOR FIGURES --- p.ix xii / INDEX FOR TABLES --- p.xiii / ABSTRACT (Chinese and English) --- p.xiv-xvi / TABLE OF CONTENT --- p.xvii / Chapter 1. --- INTRODUCTION --- p.1-37 / Chapter 2. --- OBJECTIVES --- p.38-40 / Chapter 3. --- METHODS AND MATERIALS --- p.41 -70 / Chapter 4. --- RESULTS AND DISCUSSION --- p.71-130 / Chapter 5. --- GENERAL DISCUSSION AND CONCLUSION --- p.131-133 / BIBLIOGRAPHY --- p.134-166