This thesis explores the role of lipid mediators (LM) in osteoarthritis (OA), examining their profiles in patients and how therapeutic interventions influence these profiles. The first part reviews... Show moreThis thesis explores the role of lipid mediators (LM) in osteoarthritis (OA), examining their profiles in patients and how therapeutic interventions influence these profiles. The first part reviews the therapeutic potential of LM, particularly in non-weight-bearing joints, validated through the Hand OA Prednisolone Efficacy (HOPE) study. The second part focuses on LM regulation during the inflammatory response, identifying their role in innate and adaptive immunity, particularly in monocyte-derived macrophages. The third part investigates the mechanisms by which pro-inflammatory and pro-resolving LMs function, using 17-HDHA and oleic acid as models to study their effects on cellular behavior and inflammation resolution. Show less
Background: Patients with immune-mediated inflammatory diseases (IMIDs) on immunosuppressants (ISPs) may have impaired long-term humoral immune responses and increased disease activity after SARS... Show moreBackground: Patients with immune-mediated inflammatory diseases (IMIDs) on immunosuppressants (ISPs) may have impaired long-term humoral immune responses and increased disease activity after SARS-CoV-2 infection. We aimed to investigate long-term humoral immune responses against SARS-CoV-2 and increased disease activity after a primary SARS-CoV-2 infection in unvaccinated IMID patients on ISPs. Methods: IMID patients on active treatment with ISPs and controls (i.e. IMID patients not on ISP and healthy controls) with a confirmed SARS-CoV-2 infection before first vaccination were included from an ongoing prospective cohort study (T2B! study). Clinical data on infections and increased disease activity were registered using electronic surveys and health records. A serum sample was collected before first vaccination to measure SARS-CoV-2 anti-receptor-binding domain (RBD) antibodies. Results: In total, 193 IMID patients on ISP and 113 controls were included. Serum samples from 185 participants were available, with a median time of 173 days between infection and sample collection. The rate of seropositive IMID patients on ISPs was 78% compared to 100% in controls (p < 0.001). Seropositivity rates were lowest in patients on anti-CD20 (40.0%) and anti-tumor necrosis factor (TNF) agents (60.5%), as compared to other ISPs (p < 0.001 and p < 0.001, respectively). Increased disease activity after infection was reported by 68 of 260 patients (26.2%; 95% CI 21.2-31.8%), leading to ISP intensification in 6 out of these 68 patients (8.8%). Conclusion: IMID patients using ISPs showed reduced long-term humoral immune responses after primary SARS-CoV-2 infection, which was mainly attributed to treatment with anti-CD20 and anti-TNF agents. Increased disease activity after SARS-CoV-2 infection was reported commonly, but was mostly mild. Show less
BackgroundPatients with immune-mediated inflammatory diseases (IMIDs) on immunosuppressants (ISPs) may have impaired long-term humoral immune responses and increased disease activity after SARS-CoV... Show moreBackgroundPatients with immune-mediated inflammatory diseases (IMIDs) on immunosuppressants (ISPs) may have impaired long-term humoral immune responses and increased disease activity after SARS-CoV-2 infection. We aimed to investigate long-term humoral immune responses against SARS-CoV-2 and increased disease activity after a primary SARS-CoV-2 infection in unvaccinated IMID patients on ISPs.MethodsIMID patients on active treatment with ISPs and controls (i.e. IMID patients not on ISP and healthy controls) with a confirmed SARS-CoV-2 infection before first vaccination were included from an ongoing prospective cohort study (T2B! study). Clinical data on infections and increased disease activity were registered using electronic surveys and health records. A serum sample was collected before first vaccination to measure SARS-CoV-2 anti-receptor-binding domain (RBD) antibodies.ResultsIn total, 193 IMID patients on ISP and 113 controls were included. Serum samples from 185 participants were available, with a median time of 173 days between infection and sample collection. The rate of seropositive IMID patients on ISPs was 78% compared to 100% in controls (p < 0.001). Seropositivity rates were lowest in patients on anti-CD20 (40.0%) and anti-tumor necrosis factor (TNF) agents (60.5%), as compared to other ISPs (p < 0.001 and p < 0.001, respectively). Increased disease activity after infection was reported by 68 of 260 patients (26.2%; 95% CI 21.2–31.8%), leading to ISP intensification in 6 out of these 68 patients (8.8%).ConclusionIMID patients using ISPs showed reduced long-term humoral immune responses after primary SARS-CoV-2 infection, which was mainly attributed to treatment with anti-CD20 and anti-TNF agents. Increased disease activity after SARS-CoV-2 infection was reported commonly, but was mostly mild. Show less
The global obesity pandemic is one of the most significant long-term challenges for healthcare in the current era. Obesity is strongly associated with disrupted glucose and lipid metabolism, a pro... Show moreThe global obesity pandemic is one of the most significant long-term challenges for healthcare in the current era. Obesity is strongly associated with disrupted glucose and lipid metabolism, a pro-inflammatory state of the immune system, and has a causal role in the development of cardiometabolic diseases. The medical science is challenged to find new targets in the fight against this worldwide silent pandemic.We investigated how the gut microbiota influences local and systemic lipid metabolism and immune system of the host and the relationship to pathophysiology of atherosclerosis. The central question was "Does the gut microbiota have a anti-atherogenic potential?" Our studies have shown that oral administration of the bacterium A. muciniphila positively influences the host's lipid metabolism. In addition, oral administration of this bacterium triggers an anti-inflammatory immune response. These findings suggest that A. muciniphila has anti-atherogenic potential. Furthermore, we provided critical insights into two commonly accepted and widely used research methods in cardiometabolic and microbiome research, namely Bone Marrow Transplantation (BMT) and 16S rRNA sequencing. These insights should be taken into account in the research design and interpretation of the research data when applied. In another study, we demonstrated that the gut microbiota increases the cytokine reactions of immune cells after BMT. This phenotype can be transferred to immune cells of healthy controls through Fecal Microbiota Transplantation, implying that this phenotype is independent of BMT-induced gut damage, leaky gut syndrome, and microbiota-mediated. In summary, our studies show that the gut microbiota has anti-atherogenic potential by playing a causal role in the modulation of lipid metabolism and the host's immune system. Show less
Increasing evidence has shown that immune checkpoint molecules of the T-cell immunoglobulin and mucin domain (Tim) family are associated with diverse physiologic and pathologic processes. Previous... Show moreIncreasing evidence has shown that immune checkpoint molecules of the T-cell immunoglobulin and mucin domain (Tim) family are associated with diverse physiologic and pathologic processes. Previous studies of the role of Tim-1 in atherosclerosis using anti-Tim-1 antibodies have yielded contradictory results. We thus aimed to investigate atherosclerosis development in Tim-1 deficient mice.Mice with a specific loss of the Tim-1 mucin-domain (Tim-1Δmucin) and C57BL/6 (WT) mice received a single injection of a recombinant adeno-associated virus encoding murine Pcsk9 (rAAV2/8-D377Y-mPcsk9) and were fed a Western type diet for 13 weeks to introduce atherosclerosis.Tim-1Δmucin mice developed significantly larger lesions in the aortic root compared to WT mice, with significantly more macrophages and a trend towards a larger necrotic core. Furthermore, Tim-1Δmucin mice showed a significant loss of IL-10+ B cells and regulatory B cell subsets and increased pro-atherogenic splenic follicular B cells compared to WT mice. Moreover, Tim-1Δmucin mice displayed a dramatic reduction in Th2-associated immune response compared to controls but we did not observe any changes in humoral immunity.In summary, Tim-1Δmucin mice displayed a profound impairment in IL-10+ B cells and an imbalance in the Th1/Th2 ratio, which associated with exacerbated atherosclerosis. Show less
The complement system is an important part of the innate immune system and can be divided in three different pathways; the classical, the lectin and the alternative pathway. In this thesis the... Show moreThe complement system is an important part of the innate immune system and can be divided in three different pathways; the classical, the lectin and the alternative pathway. In this thesis the role of C1q is investigated, which is the recognition molecule of the classical pathway. With the usage of epidemiological projects the clinical presentation of C1q deficient patients is investigated and the association of C1q in patients with Neuropsychiatric Systemic Lupus Erythematosus. Furthermore, using cellular based project the production and secretion of C1q by (non) immune cells is determined. Overall, this thesis is a nice overview about the importance of C1q in keeping the homeostasis and the role of C1q in disease. Show less
Sun, M.; Chang, Wen-Te; Wijk, E.P.A. van; He, M.; Koval, V.V.; Lin, M.K.; ... ; Wang, M. 2017
In this thesis, metabolomics is used to study the role of the host-virus interaction on a metabolic level. A special emphasis is directed on the role of inflammation and oxidative stress on... Show more In this thesis, metabolomics is used to study the role of the host-virus interaction on a metabolic level. A special emphasis is directed on the role of inflammation and oxidative stress on the metabolic level, as part of the innate immune response against viral infection. We chose respiratory syncytial virus (RSV) and hepatitis B virus (HBV) as candidate viruses to metabolically study their role in acute respiratory infection and chronic hepatitis B infection. Secondly we also investigated infant metabolic and immunological consequences of in utero exposure to antiretroviral intervention and human immunodeficiency virus (HIV). Collectively, established targeted metabolomics approaches in conjunction with newly developed metabolomics methodologies and complemented with other “omics” techniques, were used to address pertinent questions related to host metabolic functioning and alterations during viral infection. In vitro RSV studies together with in vivo patient based studies relating to chronic HBV infection and in utero exposure too antiretroviral and HIV were used to address these questions. The work is divided into three research parts containing: i. the analytical methodology development work, ii. in vitro based metabolomics and iii. patient based metabolomics. Show less
Preface: The content of this thesis is based on research that was conducted at the travel and vaccination clinic at Leiden University Medical Centre (LUMC). This clinic provides pre-travel care to... Show morePreface: The content of this thesis is based on research that was conducted at the travel and vaccination clinic at Leiden University Medical Centre (LUMC). This clinic provides pre-travel care to the general population, and to special groups of travellers, such as patients who use immunosuppressants or who have chronic diseases. The clinic is closely connected to the department of Infectious Diseases at LUMC. The setting of a travel clinic within an academic medical hospital, provides unique circumstances for medical research, like an experienced team of nurses, expertise regarding immunization, a constant flux of travellers and the knowledge and infrastructure that is required for research into microbiology, virology and parasitology. Examples of research that stem from this clinic are projects on immunization against malaria, yellow fever, travellers' diarrhea, poliomyelitis and hepatitis B, vaccination of immunocompromised patients, and projects on travel related acquisition of extended spectrum ß-lactamase producing Enterobacteriacae and on the utility of post-travel screening of asymptomatic travellers for parasites. Show less
In cancer and chronic infectious diseases, immune checkpoint-blockade of inhibitory receptors can enhance T-cell immunity. In tuberculosis (TB), a chronic infectious disease, prolonged antigen... Show moreIn cancer and chronic infectious diseases, immune checkpoint-blockade of inhibitory receptors can enhance T-cell immunity. In tuberculosis (TB), a chronic infectious disease, prolonged antigen exposure can potentially drive terminal T-cell differentiation towards functional 'exhaustion': in human TB T-cells express PD-1 (programmed cell death protein-1) and CTLA-4 (cytotoxic T-lymphocyte-associated protein-4). However, in murine TB not PD-1 but rather killer cell lectin-like receptor subfamily-G1 (KLRG1) was a superior indicator of terminal T-cell differentiation. We therefore compared expression of KLRG1, PD-1 and CTLA-4 on T-cells in different stages of human TB, and also analysed their induction following BCG-vaccination. KLRG1, PD-1 and CTLA-4-expression were highest on in vitro BCG-stimulated CD4(+) T-cells following recent TB-treatment; KLRG1 and PD-1-expression on CD4(+) T-cells in active - but not latent TB were only slightly increased compared to healthy donors. BCG-vaccination induced KLRG1-expression on BCG-stimulated CD8(+) but not CD4(+) T-cells, while neither PD-1 nor CTLA-4-expression increased. KLRG1-expressing CD8(+) T-cells exhibited markedly decreased proliferation, whereas PD-1(+) T-cells proliferated after in vitro BCG-stimulation. Thus, we demonstrate the presence of increased KLRG1-expressing T-cells in TB-treated individuals, and present KLRG1 as a marker of decreased human T-cell proliferation following BCG-vaccination. These results expand our understanding of cell-mediated immune control of mycobacterial infections. (c) 2015 Elsevier Ltd. All rights reserved. Show less
Insects are the most diverse group of animals on earth. They inhabit nearly all terrestrial habitats. One of the factors underlying this success is the ability of insect eggs to survive in adverse... Show moreInsects are the most diverse group of animals on earth. They inhabit nearly all terrestrial habitats. One of the factors underlying this success is the ability of insect eggs to survive in adverse conditions. For a long time the ability to survive these adverse conditions has been attributed to maternal investment in the form of a protective eggshell. In this thesis, I show that contrary to common belief, insect eggs are far from helpless. The insect egg itself develops a cellular layer around the egg called the serosa. This serosa protects the developing embryo from dehydration which enables it to survive in dry habitats. The serosa furthermore protects against infection, mounting an impressive immune response upon the entry of bacteria in the egg. The data presented in this thesis show the importance of the serosa in the survival of the insect egg. I propose that this multifunctional serosa contributed to the great success of insects. Show less
Type I immune responses play an essential role in the control of mycobacterial infections. Mutations in the genes involved in the type I cytokine pathway were found in patients with Mendelian... Show moreType I immune responses play an essential role in the control of mycobacterial infections. Mutations in the genes involved in the type I cytokine pathway were found in patients with Mendelian susceptibility to mycobacterial diseases. These patients are highly susceptible to infections with non-tuberculous mycobacteria (NTM), which are usually poorly pathogenic. The first part of this thesis focuses on the relation between the genotype and phenotype in the cause of an impaired immunity leading to the susceptibility to NTM infections. The role of genetic factors in the control of infections with more virulent tuberculous mycobacteria is less evident. The second part of this thesis focuses on putative non-genetic causes of an impaired immunity in the control of tuberculous mycobacterial diseases. In tuberculosis patients type I immune responses regulated by interferon-_ are also repressed. Virally induced interferons, other than interferon-_, may be involved in this repression, thereby influencing the immunopathogenesis of tuberculosis. Show less
Cervical cancer is induced by HPV in virtually all cases, but it is still unknown how these virus-positive tumors arise in the face of immunity. In this thesis we examined the role of different... Show moreCervical cancer is induced by HPV in virtually all cases, but it is still unknown how these virus-positive tumors arise in the face of immunity. In this thesis we examined the role of different arms of the adaptive immune response on cervical cancer. In previous studies, it was shown that cancer patients do have a detectable immune response against the HPV16 E6 and E7 antigens. However, in general this response was not associated with cytokine production. In the present study, the mechanism underlying this dysfunctional immune response was investigated by studying the presence, specificity and function of the local T-cell response in patients with HPV-induced cervical malignancies at different stages of disease. Low CD8/Treg ratio is a significant independent unfavorable prognostic factor in cervical cancer patients. Frequently, the tumor is also infiltrated with HPV-specific CD4+ and CD8+ T-cells which can potentially attack the tumor. The infiltrating T-cells also include HPV-specific regulatory T-cells which are able to suppress the reactivity of neighboring T-cells. Their presence may explain the failure of the immune system to control HPV-induced tumors. Show less
This thesis focuses on the generation of MHC ligands and their use in analyzing T cell immunity, both in mouse and men. It is roughly split into two sections: the first part deals specifically with... Show moreThis thesis focuses on the generation of MHC ligands and their use in analyzing T cell immunity, both in mouse and men. It is roughly split into two sections: the first part deals specifically with the rules governing the generation of MHC ligands, while the second part describes technological advances in the use of these MHC ligands to analyze T cell immunity. The first part of this thesis starts with an introduction on antigen presentation, covering both the different mechanisms through which epitopes are generated and the process by which epitopes are presented to T cells. Emphasis lies on the discoveries in this field of the last decade. This introduction is followed by two chapters on the generation of antigenic epitopes. Chapter two describes the analysis of protease activity in the endocytic pathway, while chapter three investigates the antigenic source of epitopes generated during cross-presentation. The second part of this thesis starts with a review on the status of MHC multimer technology as a tool to analyze antigen specific T cell populations. Chapter five then describes a high-throughput approach to generate a vast array of different peptide-MHC complexes for several human MHC alleles, allowing for faster and more complex applications of MHC multimer technology. In the next chapter, the peptide-exchange technology of chapter 5 is used for the development of another novel strategy: multidimensional encoding of peptide-MHC complexes. This chapter describes the development, validation and use of this encoding technique that allows the parallel detection of antigen-specific T cell responses of up to 25 T cell populations in one single sample. Finally, this thesis concludes with a summary and discussion chapter, giving a short overview of the presented data and discussing its relevance in the field of antigen presentation. Show less
