For the second approach, monoclonal antibodies were raised against rabbit, rat, mouse and human C6. The two most interesting antibodies were raised against human C6 and inhibited complement-mediated haemolysis in a cell-based assay. Both of these antibodies were species specific, excluding the possibility of testing their therapeutic properties in animal models of complement-mediated disease. Instead, an ex vivo model of cardiopulmonary bypass was established and used to test the ability of these antibodies to block soluble C5b-9 formation. Neither antibody inhibited soluble C5b-9 formation, suggesting that they might be interfering with the insertion of C6 into the cell membrane during MAC assembly.

No description available.

Hippocampal neurogenesis occurs within the subgranular zone of the dentate gyrus and is important for learning and memory. Neurogenesis is impaired in many pathological conditions; an observation that may account for learning and memory deficits in patients suffering from these conditions. Studies on immune-deficient mice show reduced hippocampal neurogenesis and associated learning and memory impairments in mice devoid of CD4+ T lymphocytes. Neuropeptides are potential candidates for mediating neuro-immune interactions. Vasoactive Intestinal Peptide (VIP) is a neuropeptide, released by firing interneurons from the stem cell niche, that modulates hippocampal neurogenesis via VPAC1/2 receptors. VIP receptors are also present on T lymphocytes. Microglia are innate immune cells that regulate hippocampal neurogenesis. They are ideally placed to communicate with T lymphocytes that normally reside outwith the brain parenchyma. Given the nescience underlying T lymphocyte regulation of hippocampal neurogenesis, we sought to investigate the hypothesis that VIP modulates T lymphocytes to release cytokines to regulate hippocampal neurogenesis via interaction with microglia. We have shown that T lymphocytes supernatant increases the proliferation of hippocampal nestin-expressing cells. This effect is further enhanced under VIP treatment via VPAC1 receptor subtype. Examining possible cytokine involvement, we found that IL-4 mediates proliferation. Using Mac-1-SAP to deplete resident microglia, we demonstrated that supernatant acts primarily via microglia to increase supernatant effects. T lymphocytes induce microglia to upregulate cytokines and mediators such as IL-10 and BDNF. Phenotyping showed an additional neurogenic effect under VIP treated supernatant. Our results show VPAC1 receptor subtype expressed by CD4+ T lymphocytes mediates VIP proliferative effects on hippocampal precursor cells via IL-4 cytokine release. Microglia are key for mediating this effect via release of mediators. The findings of this study implicate a novel mechanism for VPAC1 CD4+ T lymphocyte receptor as a neuro-immune mediator of hippocampal neurogenesis, and from a therapeutic perspective, shows that the effect can be pharmacologically manipulated.

CD4\(^+\) and CD8\(^+\) T cell populations can be divided into subpopulations based on expression of surface markers CCR7 and CD45RA. The resulting populations are referred to as naive, central memory, effector memory and effector memory RA\(^+\) (EMRA). The aim of this study was to identify potential lineage relationships between these subpopulations for both CD4\(^+\) and CD8\(^+\) T cells through microarray analysis. The genes found to distinguish between these subpopulations include many molecules with known functions in T cell differentiation, including CCR7, CD45RA, granzymes, L-selectin and TNF receptors. Several genes from the tetraspanin family of proteins were found to be differentially expressed at mRNA and protein level; suggesting a possible role for these genes in CD4\(^+\) and CD8\(^+\) T cell activation, migration and lysosomal function. Other genes identified, such as LRRN3 and CXCR5 which were expressed highest on naive and CM T cells respectively, provide interesting gene targets to follow up on their function in these T cell populations. Microarray data was validated through Real Time PCR and suggests that both CD4\(^+\) and CD8\(^+\) T cells differentiate along a linear pathway of naive to central memory to effector memory. The transcriptional programmes responsible for these differentiation steps were distinct between CD4\(^+\) and CD8\(^+\) T cells, although additional elements were common to both subsets.

An affordable vaccine against all serogroups of Neisseria meningitidis causing reoccurring epidemics in sub-Saharan Africa is needed. Native outer membrane vesicles (NOMV) with over-expressed factor H binding protein (fHbp) represent a promising vaccine approach. We investigated the contribution of fHbp variant 1 amino acidic sequence to the cross-reactivity of the antibody response generated by NOMV OE fHbp. Coupling structure-sequence analysis of fHbp with epidemiological data of meningococcal prevalence in Africa, we selected four fHbp v.1 IDs (1, 5, 9, 74), to generate isogenic mutants of a serogroup W African isolate, over-expressing each of the them. NOMV from the mutants were purified, characterized, and the antibody response generated in mice was investigated, and compared to the corresponding recombinant fHbp. This is the first study indicating that the amino acid sequence of fHbp influences the specificity of the antibody response generated, not only as recombinant protein, but also when over-expressed on NOMV. In mice NOMV OE fHbp induced a fast, long-lasting antibody response, with high IgM and IgG antibody levels 7 days after immunization, and germinal centers induced. LipidA modifications do not impact primary antibody response, while precipitation of the antigen on alum attenuated the early antibody response, but enhance its longevity.

Parasitic helminths are able to survive within their hosts due to their ability to dampen immune responses by secreting molecules with anti-inflammatory and tissue repair properties. Reflecting this, there is increasing evidence of an inverse correlation between parasitic worm infection and the incidence of allergic and autoimmune disorders on a global scale. Such epidemiological evidence has led to the “hygiene hypothesis” which postulates that the recent rapid eradication of parasitic worms in developed countries has resulted in unbalanced hyper-reactive immune systems and consequently, inflammatory disease. As “worm therapy” per se is not ideal, this in turn triggered the idea that exploiting the ability of helminth-derived “immunomodulators” to dampen pathological host inflammation would potentially allow identification of the key pathogenic events in models of human inflammatory disease and hence provide a starting point for development of new and safer therapeutics. Consistent with this, as a serendipitous side-effect of its anti-inflammatory actions, ES-62, a phosphorylcholine (PC)-containing glycoprotein secreted by the filarial nematode, Acanthocheilonema viteae exhibits therapeutic potential in mouse models of inflammatory disorders such as asthma, lupus and rheumatoid arthritis (RA). RA is a chronic autoimmune inflammatory disorder that affects 1 % of the population in industrialized countries, with no known cure. This disorder causes joint destruction and leads to reduced mobility and disability. Deregulation of T cell activation has long been considered to be a major force driving inflammation and thus to date, therapies have focused on systemic anti-inflammatory treatments, which generally leave individuals immunosuppressed and open to infection. Thus, interest has begun to focus on the role(s) that synovial fibroblasts (SF) in the joint play in the early onset of the disease, the maintenance of established inflammation and even in the spread of disease to unaffected joints. This reflects that despite not being part of the immune system, SF produce pro-inflammatory cytokines during the pathogenesis of RA and also directly mediate joint destruction by secreting matrix metalloproteinases (MMPs) that damage cartilage and bone. Indeed, there is increasing evidence that the local pro-inflammatory environment pertaining in the joints drives SF to become 3 imprinted pathogenic aggressors that initiate, drive and spread joint inflammation and bone resorption during development of collagen-induced arthritis (CIA), a mouse model of RA. Intriguingly, therefore, whilst it is established that protection afforded by ES-62 against joint inflammation and bone destruction in CIA is associated with reduced production of the pathogenic cytokine, IL-17 by  and CD4+ T cells, recent evidence suggested that ES-62 could also act directly to suppress the aggressive hyper-inflammatory phenotype of SF in the joint. The molecular mechanisms involved were not defined but interestingly, given that SF express the ES-62 target TLR4 and are the only cells in the joint to express the IL-22 receptor, the parasite product appeared to harness the inflammation-resolving and/or tissue repair actions of IL-22 to suppress SF responses during the established phase of disease. Thus the core goal of this thesis was to advance our fundamental understanding of how SF become imprinted pathogenic aggressors that initiate, drive and spread joint inflammation and bone resorption in the CIA mouse model, as a surrogate for the pathogenic events in the joints in RA. In particular, the primary major aim was to investigate the impact of the local pro-inflammatory environment pertaining during disease, specifically focusing on the signalling and epigenetic mechanisms by which IL-17 and IL-22 potentially (counter)regulate the pathogenic phenotype of SF. Complementing this, another major aim was to establish whether ES-62 acted directly to modulate the phenotype of SF and thus, to identify the key mechanisms by which ES-62 could prevent SF from promoting inflammation and bone destruction and in this way render them insensitive to pro-inflammatory signals. From a therapeutic point of view, being a large immunogenic molecule, ES-62 is not suitable for use in the clinic and thus candidate small molecule analogues (SMAs) of ES-62, based around its active PC moiety have been designed, some which mimic its therapeutic potential in a variety of inflammatory disorders. Thus, it was also important to address whether ES-62 and its SMAs were similarly able to affect SF and prevent their pathogenicity. These studies revealed that the microenvironment of the joint during induction and progression of CIA did indeed result in remodelling of the epigenetic landscape of SF and that such cell reprogramming was associated with the acquisition of a hyperinflammatory, tissue destructive phenotype. Such 4 reprogramming could be recapitulated in vitro, at least in part, by chronic exposure of normal SF to pro-inflammatory cytokines such as IL-17 and IL-1 pathogenic mediators that are found at high levels in the arthritic joint. Such reprogramming was dependent on ERK and STAT3 signalling converging on miR-155-mediated regulation of inflammatory networks via global DNA hypomethylation. ES-62 was able to counteract this by suppressing the levels of ERK, STAT3 and miR-155 signalling but rather surprisingly, this did not result in abrogation of this hypomethylated epigenetic landscape. Rather, whereas the SMA 12b appeared to act simply by preventing/reversing global DNA demethylation to suppress the induction of genes that drive pathogenesis in CIA, ES-62 induced further global DNA hypomethylation and modulation of the epigenetic landscape by inducing HDAC1: collectively these findings suggested that ES-62 might additionally induce (homeostatic) inflammation-resolving and tissue repair genes that would have translational impact in established disease. In any case, these studies suggest that the proposal to use the global DNA methylation status of RA patients as a biomarker of disease should be treated with caution.

For the most part, diagnostic clinical microbiology still relies on 19th century ideas and techniques, particularly microscopy and laboratory culture. In this thesis I investigate the utility of a new approach, whole-genome sequencing (WGS), to tackle current issues in infectious disease. I present four studies. The first demonstrates the utility of WGS in a hospital outbreak of Acinetobacter baumannii. The second study uses WGS to examine the evolution of drug resistance following antibiotic treatment. I then explore the use of WGS prospectively during an international outbreak of food-borne Escherichia coli infection, which caused over 50 deaths. The final study compares the performance of benchtop sequencers applied to the genome of this outbreak strain and touches on the issue of whether WGS is ready for routine use by clinical and public health laboratories. In conclusion, through this programme of work, I provide ample evidence that whole-genome sequencing of bacterial pathogens has great potential in clinical and public health microbiology. However, a number of technical and logistical challenges have yet to be addressed before such approaches can become routine.

Tuberculosis is a global problem, with little change in antibiotic therapy over the last fifty years, but with the emergence of both multi-drug resistant disease and extensive drug resistant disease further treatments are needed to ensure successful management of the disease. Severe vitamin D deficiency is prevalent in patients with tuberculosis and the immunomodulatory mechanisms of elements of the vitamin D axis, including vitamin D binding protein (DBP) and vitamin D receptor (VDR) have been explored in part. Aims This thesis will ascertain the role of polymorphisms in vitamin D axis genes in determining response to vitamin D in tuberculosis patients. Additionally it will aim to determine whether the interaction between underlying genotype, baseline vitamin D level and other elements of the vitamin D axis has the potential to influence clinical outcome and further investigate in vitro effects of vitamin D and elements of the vitamin D axis in influencing the frequency and functionality of monocytes and T cells, both of which are key elements in the immune response to tuberculosis infection. Results Associations between vitamin D baseline and response to supplementation appear to have a genetic association with DBP, VDR and DHCR7 genotypes and varying DBP haplotypes appear to determine the level of DBP at baseline measurement. The effect of vitamin D has an immunomodulatory role in both monocyte response and T regulatory activity, with a clear effect of vitamin D on cytokine response. Conclusion There appears to be a role for vitamin D in the treatment of tuberculosis but further questions are raised regarding the benefits and risks of immune response modulation in an inflammatory/ cytopathogenic condition such as tuberculosis.

Somatic cell reprogramming towards a pluripotent stem cell-like state occurs in an organized way, with rapid changes in gene expression during the first days of induction. Little is known about the mechanisms that lead to DNA double strand breaks (DSB) and genome instability during reprogramming. Amongst genes upregulated during reprogramming is that encoding the transcription factor B-Myb. \(B\)-\(myb\) RNA levels increase gradually from day 2 of reprogramming, earlier than those encoding pluripotency factors such as \(Nanog\). Despite its possible function as a regulator of the pluripotent state, B-Myb has a general role in the regulation of proliferation, and genome stability throughout the animal kingdom, raising the possibility that the activity of this protein is linked to the DSBs observed during reprogramming. To explore this possibility, reprogramming studies were performed in which B-Myb expression was modified: B-\(myb\)-/- MEFs were incapable of reprogramming after transduction with OSKM lentivirus (Oct4/Sox2/Klf4/c-Myc). However, unexpectedly, co-expression of B-Myb together with OSK (OSKB lentivirus), severely impaired the efficiency of reprogramming. Interestingly, the iPSC colonies appeared more ESC-like and had less DSBs. My results show that both the level of the B-Myb expression is crucial during early stages of reprogramming, indicating that B-Myb is a gatekeeper for reprogramming.

Death Receptor 3 (DR3) is a death domain (DD) containing member of the Tumour Necrosis Factor Receptor Superfamily (TNFRSF) and has a single acknowledged TNFSF ligand called TNF-like protein 1A (TL1A). Previous research has implicated roles for DR3 in host immune defence and in various inflammatory diseases such as rheumatoid arthritis, inflammatory bowel disease (IBD), atherosclerosis and allergic lung inflammation. This thesis investigated a potential role for DR3 in co-ordinating the innate immune response, using an in vivo Staphylococcus epidermidis supernatant (SES) model of acute peritoneal inflammation. A further point of investigation looked at the effect of the absence of DR3 on thickening of the peritoneal membrane induced by repeated SES inflammation. My results showed that the DR3/TL1A pathway is not essential in maintaining the number of peritoneal or blood leukocytes during naive conditions. Stromal DR3 was found to be important in co-ordinating the innate immune response after the induction of acute SES induced inflammation, with significantly lower numbers of specific myeloid and lymphoid cell subsets accumulating in the peritoneal cavity of DR3 knockout (DR3-/-) mice. Despite this reduction in selected leukocyte numbers, the proportion of infiltrating cells exhibiting proliferation and cell death was unaffected by the absence of DR3. However reduced leukocyte numbers were associated with a significant reduction in the concentration of multiple chemoattractants in DR3-/- peritoneal supernatants compared to those from DR3+/+ mice. Quantitative RT-PCR data (qPCR) were consistent with the peritoneal membrane being a source of many of these chemoattractants. vi Results presented here identify for the first time a pro-inflammatory role for stromal DR3 in the innate immune response. However after repeatedly inducing inflammatory conditions DR3 promoted thickening of the peritoneal membrane, while an absence of DR3 prevented aberrant inflammation-induced tissue fibrosis.