O objetivo do presente trabalho foi investigar o efeito da hiperglicemia na alteração da homeostase imunológica mediada pelas células dendríticas (DCs) em resposta a uma bacteremia induzida por raspagem e alisamento radicular (RAR) em indivíduos com periodontite crônica generalizada (GCP). Foram selecionados 60 indivíduos igualmente divididos em quatro grupos: controles normoglicêmicos saudáveis, normoglicêmicos com GCP (NG+GCP), pré-diabéticos com GCP (PD+GCP) e diabéticos tipo 2 com GCP (T2DM+GCP). Os indivíduos com GCP receberam RAR, o que induziu uma bacteremia aguda e os controles saudáveis receberam apenas raspagem supragengival. Todos os participantes foram avaliados no início do estudo, 24hs, 1 mês e 3 meses após a raspagem. A frequência de células dendríticas mielóides (mDCs) CD1c+, mDCs CD141+, células dendríticas plasmocitoides (pDCs) CD303+ e a expressão dos receptores CCR6 (presente em altos níveis em células dendríticas imaturas) e CCR7 (presente em altos níveis em células dendríticas maduras) foram avaliados por citometria de fluxo. Foi utilizada técnica de PCR em tempo real para investigar a presença de Porphyromonas gingivalis (P. gingivalis) no biofilme e abrigada pelas DCs. No início do estudo, os indivíduos hiperglicêmicos com GCP tinham níveis de DCs significativamente mais baixos do que os indivíduos normoglicêmicos com ou sem GCP. Após a bacteremia induzida por RAR, observou-se um aumento significativo nos níveis de CD1c+ e CD1c+CCR6+ em todos os grupos com GCP, independentemente do status de glicemia, e esses níveis voltaram aos níveis basais após 1 mês. Em comparação com o grupo NG+GCP, o grupo T2DM+GCP apresentou níveis significativamente mais baixos de DCs ao longo de todos os períodos experimentais. Não foram observadas alterações significativas para CD303+, CD1c+ CCR7+ e CD141+ em resposta à bacteremia; CD303+ e CD141+ foram significativamente mais baixos para T2DM+GCP comparado ao grupo NG+GCP ao longo do estudo. A quantidade de P. gingivalis nas DCs estava aumentada no grupo NG+GCP no início do estudo e após 24h da RAR comparado ao controle, mas não nos grupos hiperglicêmicos. Os resultados premitiram concluir que a hiperglicemia parece afetar negativamente a presença de mDCs e pDCs no sangue periférico e a abilidade dessas células em capturar P. gingivalis. Considerando que a magnitude da expansão de mDCs em resposta a um desafio bacteriano foi semelhante, os indivíduos hiperglicêmicos permaneceram imunocomprometidos em comparação com indivíduos normoglicêmicos. / The objective of this study was to investigate the effect of hyperglycemia in the disruption of dendritic cells (DCs) mediated immune homeostasis in response to an acute short-term bacteremia in subjects with generalized chronic periodontitis (GCP). Sixty subjects equally divided into four groups were selected: normoglycemic healthy controls, normoglycemics with GCP (NG+GCP), pre-diabetics with GCP (PD+GCP), and type-2 diabetes mellitus with GCP (T2DM+GCP). Subjects with GCP received full-mouth scaling and root planning (SRP), which induced an acute bacteremia, while healthy controls received only a prophylaxis. All participants were examined at baseline, 24hs after SRP, 1 month, and 3 months. The frequency of CD1c+ myeloid DCs (mDCs), CD141+ mDCs, CD303+ plasmacytoid DCs (pDCs) and their expression of immature DC tissue homing receptor CCR6+ and secondary lymphoid organ (SLO)-homing receptor CCR7+ were analyzed by flow cytometry. The presence of Porphyromonas gingivalis (P. gingivalis) mRNA within blood DCs was analyzed by real time PCR. At baseline, hyperglycemic subjects with GCP showed lower DC levels than normoglycemic subjects with or without GCP. After SRP induced bacteremia, a significant increase in CD1c+ and CD1c+CCR6+ levels was observed in all GCP groups, which returned to baseline levels after 1 month. Compared to NG+GCP, T2DM+GCP had significantly lower levels of DCs throughout the experimental periods. No significant changes were observed for CD303+, CD1c+CCR7+ and CD141+ in response to the bacteremia; CD303+ and CD141+ were significantly lower for T2DM+GCP than NG+GCP throughout the study. P. gingivalis carriage state of DCs was increased in the NG+GCP group, but not in the hyperglycemic groups. Hyperglycemia appears to negatively affect the pool of mDCs and pDCs and the ability of blood DCs to captures bacteremic P. gingivalis. Whereas the magnitude of mDCs expansion in response to a bacterial challenge was similar, hyperglycemic subjects remained immunocompromised in comparison to normoglycemic subjects.

O objetivo do presente trabalho foi investigar o efeito da hiperglicemia na alteração da homeostase imunológica mediada pelas células dendríticas (DCs) em resposta a uma bacteremia induzida por raspagem e alisamento radicular (RAR) em indivíduos com periodontite crônica generalizada (GCP). Foram selecionados 60 indivíduos igualmente divididos em quatro grupos: controles normoglicêmicos saudáveis, normoglicêmicos com GCP (NG+GCP), pré-diabéticos com GCP (PD+GCP) e diabéticos tipo 2 com GCP (T2DM+GCP). Os indivíduos com GCP receberam RAR, o que induziu uma bacteremia aguda e os controles saudáveis receberam apenas raspagem supragengival. Todos os participantes foram avaliados no início do estudo, 24hs, 1 mês e 3 meses após a raspagem. A frequência de células dendríticas mielóides (mDCs) CD1c+, mDCs CD141+, células dendríticas plasmocitoides (pDCs) CD303+ e a expressão dos receptores CCR6 (presente em altos níveis em células dendríticas imaturas) e CCR7 (presente em altos níveis em células dendríticas maduras) foram avaliados por citometria de fluxo. Foi utilizada técnica de PCR em tempo real para investigar a presença de Porphyromonas gingivalis (P. gingivalis) no biofilme e abrigada pelas DCs. No início do estudo, os indivíduos hiperglicêmicos com GCP tinham níveis de DCs significativamente mais baixos do que os indivíduos normoglicêmicos com ou sem GCP. Após a bacteremia induzida por RAR, observou-se um aumento significativo nos níveis de CD1c+ e CD1c+CCR6+ em todos os grupos com GCP, independentemente do status de glicemia, e esses níveis voltaram aos níveis basais após 1 mês. Em comparação com o grupo NG+GCP, o grupo T2DM+GCP apresentou níveis significativamente mais baixos de DCs ao longo de todos os períodos experimentais. Não foram observadas alterações significativas para CD303+, CD1c+ CCR7+ e CD141+ em resposta à bacteremia; CD303+ e CD141+ foram significativamente mais baixos para T2DM+GCP comparado ao grupo NG+GCP ao longo do estudo. A quantidade de P. gingivalis nas DCs estava aumentada no grupo NG+GCP no início do estudo e após 24h da RAR comparado ao controle, mas não nos grupos hiperglicêmicos. Os resultados premitiram concluir que a hiperglicemia parece afetar negativamente a presença de mDCs e pDCs no sangue periférico e a abilidade dessas células em capturar P. gingivalis. Considerando que a magnitude da expansão de mDCs em resposta a um desafio bacteriano foi semelhante, os indivíduos hiperglicêmicos permaneceram imunocomprometidos em comparação com indivíduos normoglicêmicos. / The objective of this study was to investigate the effect of hyperglycemia in the disruption of dendritic cells (DCs) mediated immune homeostasis in response to an acute short-term bacteremia in subjects with generalized chronic periodontitis (GCP). Sixty subjects equally divided into four groups were selected: normoglycemic healthy controls, normoglycemics with GCP (NG+GCP), pre-diabetics with GCP (PD+GCP), and type-2 diabetes mellitus with GCP (T2DM+GCP). Subjects with GCP received full-mouth scaling and root planning (SRP), which induced an acute bacteremia, while healthy controls received only a prophylaxis. All participants were examined at baseline, 24hs after SRP, 1 month, and 3 months. The frequency of CD1c+ myeloid DCs (mDCs), CD141+ mDCs, CD303+ plasmacytoid DCs (pDCs) and their expression of immature DC tissue homing receptor CCR6+ and secondary lymphoid organ (SLO)-homing receptor CCR7+ were analyzed by flow cytometry. The presence of Porphyromonas gingivalis (P. gingivalis) mRNA within blood DCs was analyzed by real time PCR. At baseline, hyperglycemic subjects with GCP showed lower DC levels than normoglycemic subjects with or without GCP. After SRP induced bacteremia, a significant increase in CD1c+ and CD1c+CCR6+ levels was observed in all GCP groups, which returned to baseline levels after 1 month. Compared to NG+GCP, T2DM+GCP had significantly lower levels of DCs throughout the experimental periods. No significant changes were observed for CD303+, CD1c+CCR7+ and CD141+ in response to the bacteremia; CD303+ and CD141+ were significantly lower for T2DM+GCP than NG+GCP throughout the study. P. gingivalis carriage state of DCs was increased in the NG+GCP group, but not in the hyperglycemic groups. Hyperglycemia appears to negatively affect the pool of mDCs and pDCs and the ability of blood DCs to captures bacteremic P. gingivalis. Whereas the magnitude of mDCs expansion in response to a bacterial challenge was similar, hyperglycemic subjects remained immunocompromised in comparison to normoglycemic subjects.

Human Epidermal Growth Factor Receptor 2 (HER-2/neu) is a breast tumor antigen (Ag) commonly overexpressed in 30% of breast cancer cases. Both HER-2/neu-targeted DNA-based and transgene modified dendritic cell (DC)-based vaccines are potent elements in eliciting HER-2/neu specific antitumor immune responses; however, there has been no side-by-side comparison of these two different immunization methods. We utilized an in vivo murine tumor model expressing the rat neu Ag to compare the immunization efficacy between DC transduced with replication-deficient adenovirus containing neu (AdVneu), to form DCneu, and plasmid DNA (pcDNA) vaccine. DCneu displayed an upregulation of immunologically important molecules and inflammatory cytokines expression such as IL-6 that partially mediated conversion of the regulatory T (Tr) cell suppression. Wildtype FVB/N mice immunized with DCneu induced stronger HER-2/neu-specific humoral and cellular immune responses compared to plasmid DNA immunized mice. Furthermore, mice immunized with DCneu remained completely protected from tumor challenge compared to partial or no protection observed in DNA immunized mice in two tumor animal models. In FVBneuN transgenic mice, which develop spontaneous breast tumors at 4-8 months of age, DCneu significantly delayed tumor onset when immunization conducted in mice at a younger age. Taken together, we demonstrated that a HER-2/neu-gene modified DC vaccine is more potent than a plasmid DNA vaccine in inducing neu specific immune responses resulting in greater protective and preventative effects in the tumor models examined. <p>In another study, we examined the use of a DC-based cancer vaccine involving the phagocytosis of apoptotic tumor cells expressing heat shock protein 70 (HSP70). The dual role of HSP70, as an antigenic peptide chaperone and danger signal, makes it especially important in DC-based vaccination. In this study, we investigated the impacts of apoptotic transgenic MCA/HSP tumor cells expressing HSP70 on DC maturation, T cell stimulation and overall vaccine efficacy. We found that DC with phagocytosis of MCA/HSP in the early phase of apoptosis expressed more peptide-major histocompatibility class (pMHC) I complexes, stimulated stronger cytotoxic T lymphocytes (CTL) responses and induced greater immune protection against MCA tumor cell challenge, compared to mice immunized with DC that phagocytosed MCA/HSP cells in the late phase of apoptosis. Taken together, our data demonstrated that HSP70 expression on apoptotic tumor cells stimulated DC maturation and DC with phagocytosis of apoptotic tumor cells expressing HSP70 in early phase of apoptosis more efficiently induced tumor-specific CTL responses and immunity than DC with phagocytosis of apoptotic tumor cells in late phase of apoptosis. <p>Overall, we have examined variations in designing DC-based cancer vaccines in two completely different model systems. Taken together, our results may have an important impact in designing DC-based antitumor vaccines.

Human Epidermal Growth Factor Receptor 2 (HER-2/neu) is a breast tumor antigen (Ag) commonly overexpressed in 30% of breast cancer cases. Both HER-2/neu-targeted DNA-based and transgene modified dendritic cell (DC)-based vaccines are potent elements in eliciting HER-2/neu specific antitumor immune responses; however, there has been no side-by-side comparison of these two different immunization methods. We utilized an in vivo murine tumor model expressing the rat neu Ag to compare the immunization efficacy between DC transduced with replication-deficient adenovirus containing neu (AdVneu), to form DCneu, and plasmid DNA (pcDNA) vaccine. DCneu displayed an upregulation of immunologically important molecules and inflammatory cytokines expression such as IL-6 that partially mediated conversion of the regulatory T (Tr) cell suppression. Wildtype FVB/N mice immunized with DCneu induced stronger HER-2/neu-specific humoral and cellular immune responses compared to plasmid DNA immunized mice. Furthermore, mice immunized with DCneu remained completely protected from tumor challenge compared to partial or no protection observed in DNA immunized mice in two tumor animal models. In FVBneuN transgenic mice, which develop spontaneous breast tumors at 4-8 months of age, DCneu significantly delayed tumor onset when immunization conducted in mice at a younger age. Taken together, we demonstrated that a HER-2/neu-gene modified DC vaccine is more potent than a plasmid DNA vaccine in inducing neu specific immune responses resulting in greater protective and preventative effects in the tumor models examined. <p>In another study, we examined the use of a DC-based cancer vaccine involving the phagocytosis of apoptotic tumor cells expressing heat shock protein 70 (HSP70). The dual role of HSP70, as an antigenic peptide chaperone and danger signal, makes it especially important in DC-based vaccination. In this study, we investigated the impacts of apoptotic transgenic MCA/HSP tumor cells expressing HSP70 on DC maturation, T cell stimulation and overall vaccine efficacy. We found that DC with phagocytosis of MCA/HSP in the early phase of apoptosis expressed more peptide-major histocompatibility class (pMHC) I complexes, stimulated stronger cytotoxic T lymphocytes (CTL) responses and induced greater immune protection against MCA tumor cell challenge, compared to mice immunized with DC that phagocytosed MCA/HSP cells in the late phase of apoptosis. Taken together, our data demonstrated that HSP70 expression on apoptotic tumor cells stimulated DC maturation and DC with phagocytosis of apoptotic tumor cells expressing HSP70 in early phase of apoptosis more efficiently induced tumor-specific CTL responses and immunity than DC with phagocytosis of apoptotic tumor cells in late phase of apoptosis. <p>Overall, we have examined variations in designing DC-based cancer vaccines in two completely different model systems. Taken together, our results may have an important impact in designing DC-based antitumor vaccines.

<p>Vaccinia virus (VV) is the most thoroughly studied member of the Poxviridae family and the vaccine used to achieve the only successful eradication of a human disease. Over the years, it has proven itself as a useful tool for the study of antiviral immunity, vaccine development, and potentially cancer immunotherapy. VV is capable of eliciting a robust immune response; however the mechanisms by which VV accomplishes this task remain unknown. The overall goal of this thesis project is to determine how VV activates the innate immune system, and how this activation contributes to viral clearance in vivo. We determined that VV or VV-DNA activated the TLR8-MyD88 pathway in plasmacytoid dendritic cells (pDC), resulting in the production of type I interferons (IFN). We also demonstrated that TLR8-mediated production of type I IFN by pDC was crucial to efficient VV control and clearance in vivo. Moreover, we identified the polyA- and polyT-rich sequences in VV-DNA was the possible motif recognize by TLR8. Type I IFN, known for ability to establish the "antiviral state", are also critical mediators of NK cell activation. In the setting of VV infection, we demonstrated that direct action of type I IFN on NK cells, but not accessory cells such as DC, was necessary for NK cell activation in vivo. We further demonstrated that type I IFN-dependent activation of NK cells was required for optimal VV clearance in vivo. Given the importance of NK cells in anti-VV innate immunity, we next examined what role the TLR2-MyD88 pathway, critical for activation of cDC, played in the activation of NK cells. NK cells from TLR2-/- or MyD88-/- mice displayed a reduction in activation and cytolytic function, and this defect was independent of pro-inflammatory cytokine signaling. We were able to demonstrate that direct TLR2 signaling on NK cells was required for their optimal activation and function in response to VV infection. Moreover, we were able to demonstrate that TLR2-MyD88 signaling resulted in the activation of the PI3K-ERK pathway, which was necessary for NK cell cytotoxicity. In addition, we identified the NKG2D pathway as critical for efficient NK cell activation and function in response to VV infection, independent of the TLR2 pathway. Both the NKG2D and TLR2 pathways were crucial for optimal VV clearance and control in vivo. Collectively, this project illuminates the roles and mechanisms of the innate immune system in the control of VV in vivo.</p> / Dissertation

Dengue, a group of four similar viruses transmitted through the bite of a mosquito, is estimated to infect upwards of 100 million annually in over 100 nations throughout the global equatorial belt. Distribution of global dengue is highly skewed as Southeast Asian and Western Pacific regions endure 75% of the global dengue burden. Similar to other regional countries, Malaysia has been rapidly urbanizing, which has supported a hyperendemic dengue state. The biological pathway by which dengue infection causes a wide range of clinical manifestations, spanning asymptomatic to life-threatening severe complications, is not comprehensively understood. Historically, severe dengue complications have primarily occurred in children. Consequentially, the majority of the dengue biological pathway research has been conducted on children; however, extrapolation of research findings to adults may be inappropriate as dengue manifestations have differed between age groups. As developing countries undergo epidemiologic transitions and dengue continues to spread geographically to non-endemic regions, youth and adult populations have been subjected to more of the severe dengue burden. Epidemiology and laboratory-based evidence has supported both memory T-cell and antibody independent enhancement hypotheses to explain the biological pathway of severe dengue. Both hypotheses employ the central idea that a primary infection alters immune components so that during a secondary heterotypic dengue infection, an individual is more at risk for severe complications. Monocytes, immune cells that are pivotal in both hypotheses, have been highly examined through in vivo and in vitro experimentation; however, epidemiological evidence for monocyte involvement is incomplete. The primary objective of the study was to examine if a difference in absolute monocyte count, considering independent risk factors, is present in individuals with primary and secondary dengue infections. A secondary dengue infection was found to raise absolute monocyte count during the defervescence phase of dengue illness in individuals aged 15 years and older 0.71 ± 0.15 (x10^9) compared to those experiencing primary dengue infection. Gender and distance of study participants' residences from Hospital Ampang were found to be risk factors for the relationship of interest; whereas, age and race were not found to be significant risk factors. The study helps expand current knowledge of the severe dengue biological pathway with respect to immunological differences between primary and secondary dengue infections. Further research is needed to confirm and expand the findings of this initial study, specifically to include infecting dengue serotype, education, and socioeconomic status which are known dengue risk factors.

Systemic lupus erythematosus (SLE) is an autoimmune, inflammatory disease characterized by autoantibody production and an activated type I interferon system. Cardiovascular disease (CVD) is as a major cause of morbidity and mortality. The aim of this thesis was to identify genetic risk factors for CVD in SLE. The role of T cells in regulation of the interferon-α (IFNα) production by plasmacytoid dendritic cells (pDCs) was also investigated.    In paper I, a thicker intima, thinner media and increased intima/media ratio was found in young premenopausal women with SLE compared to healthy controls indicating increased cardiovascular risk. As traditional ultrasound assessment of the common carotid intima-media thickness (CCA-IMT) in SLE has given conflicting results separate measurement of the intima and media can be a useful tool to identify SLE patients at increased risk of CVD.    In paper II, an association was demonstrated in SLE between a STAT4 risk allele and ischemic cerebrovascular disease and presence of anti-phospholipid antibodies (aPL). The association remained after adjustment for traditional CVD risk factors. A possible mechanism for this association is that the risk allele leads to increased production of aPL, which promotes thromboembolism.    In paper III, a genetic locus in IRF8 was identified to be associated to coronary heart disease (CHD) in SLE. The association remained after adjustment of other CHD risk factors.  Patients with the IRF8 risk variant had increased CCA-IMT, more carotid plaques and reduced frequency of circulating B cells. Weaker binding of nuclear protein to the risk allele was demonstrated, suggesting a regulatory function of the IRF8 risk variant.    In paper IV, activated T cells were found to strongly enhance the IFNα production by pDC stimulated with RNA-containing immune complexes via GM-CSF and IL-3. Activated SLE T cells enhanced the IFNα production to the same extent as T cells from healthy controls. This finding together with previous observations in SLE of increased levels of GM-CSF and IL-3 suggests that T cells contribute to the activated type I interferon system in SLE.    In conclusion, this thesis demonstrates that genetic predisposition is important for CVD in SLE and describes a new role for T cells in the pathogenesis of SLE.

Dendritic cells (DCs) are promising mediators of anti-tumour immune responses. Unfortunately, a major hindrance to the development of highly effective DC vaccines is their short lifespan. Tumour antigen presentation may also not be optimal. We hypothesize that the introduction of exogenous survival factors (SFs) would prolong DC longevity and that modulation of TAA glycosylation will improve antigen presentation. To this end, we have constructed bicistronic lentivectors (LVs) encoding the xeno Tumour-Associated-Antigen (TAA), rHER-2/neu, and one of five candidate SFs. We demonstrated that our LVs can effectively protect transduced DCs from apoptosis when subjected to apoptosis-inducing conditions. TAA glycosylation has been proposed to obstruct the processing and presentation of peptides on MHC molecules. To address this second issue, we have engineered a LV that encodes a partially deglycosylated rHER-2/neu. Overall, we have generated the tools to alter intrinsic DC properties, which we believe will be integral to improving DC vaccine efficacy.

Dendritic cells (DCs) are promising mediators of anti-tumour immune responses. Unfortunately, a major hindrance to the development of highly effective DC vaccines is their short lifespan. Tumour antigen presentation may also not be optimal. We hypothesize that the introduction of exogenous survival factors (SFs) would prolong DC longevity and that modulation of TAA glycosylation will improve antigen presentation. To this end, we have constructed bicistronic lentivectors (LVs) encoding the xeno Tumour-Associated-Antigen (TAA), rHER-2/neu, and one of five candidate SFs. We demonstrated that our LVs can effectively protect transduced DCs from apoptosis when subjected to apoptosis-inducing conditions. TAA glycosylation has been proposed to obstruct the processing and presentation of peptides on MHC molecules. To address this second issue, we have engineered a LV that encodes a partially deglycosylated rHER-2/neu. Overall, we have generated the tools to alter intrinsic DC properties, which we believe will be integral to improving DC vaccine efficacy.

The host immune response to parasitic helminths is usually characterized by a Th2 phenotype. As the Jagged/Notch pathway has been implicated in driving Th2 development, it was hypothesized that host macrophages and dendritic cells (DCs) could detect helminth products and mount an appropriate response via this pathway. Schistosoma mansoni soluble egg antigen (SEA) rapidly up-regulated expression of the Notch ligand, Jagged 1, in both mouse and human macrophages, as well as in conventional mouse DCs. Other factors associated with Th cell development, including the Th1-promoting factor IL-12 p40, as well as another potential Th2-promoting factor, interleukin (IL)-33, were not transcriptionally responsive to SEA in these same cell types, thus indicating the selectivity of the response. Inducible gene expression was modified by the presence of the macrophage growth factor colony-stimulating factor (CSF)-1, which inhibited Jagged 1 induction by SEA and lipopolysaccharide (LPS), but enhanced LPS-induced IL-12p40 expression. Despite the observation that SEA upregulated Jagged 1 in both macrophages and DCs, only SEA-pulsed DCs promoted IL-4 production upon T-cell activation, suggesting that Jagged 1 induction alone is insufficient for instructing Th2 development. A recombinant form of the extracellular region of Jagged 1 did, however, enhance IFN-γ production in splenocytes, thus implying that the rapid induction of Jagged 1 in macrophages and DCs can regulate T cell responses. A potential role for SEA-induced Jagged 1 in autocrine responses in macrophages was also investigated through studies with recombinant extracellular Jagged 1, as well as ectopic expression of Jagged 1 in macrophages. A comparison of the responses initiated in macrophages by SEA and the bacterial endotoxin lipopolysaccharide (LPS) revealed common activation of extracellular signal regulated kinase-1/2 (ERK-1/2) and p38 phosphorylation. However, only LPS triggered IκB degradation, phosphorylation of c-Jun N-terminal kinase (JNK) and phosphorylation of Tyr701 of signal transducer and activator of transcription 1 (STAT1). SEA robustly activated signalling in HEK293 cells expressing either Toll-like receptor 2 (TLR2) or TLR4/MD2, as well as variably in cells expressing TLR3. Jagged 1 upregulation by SEA was not abrogated in TLR4 knockout macrophages, in contrast to the LPS response. Pharmacological inhibition of the ERK-1/2 pathway impaired both SEA- and LPS-inducible Jagged 1 expression in macrophages. In conclusion, the data within this thesis suggests that Jagged 1 is an ERK-dependent target of TLR signalling that has a macrophage-specific function in the response to SEA.