In dit proefschrift hebben wij de invloed van mestcellen in dierexperimentele modellen voor reumatoïde artritis en aderverkalking bestudeerd met een focus op de rol van mestcellen in de (sub)... Show moreIn dit proefschrift hebben wij de invloed van mestcellen in dierexperimentele modellen voor reumatoïde artritis en aderverkalking bestudeerd met een focus op de rol van mestcellen in de (sub)-klinische fases van het ziekteproces, waarin er een actieve immuunrespons ontwikkeld was. Ook hebben wij de aanwezigheid van verschillende soorten antistoffen in het serum van cardiovasculaire patiënten onderzocht. Wij hebben de niveaus van antilichamen gecorreleerd aan klinische observaties zoals body mass index (BMI), lipidenprofiel, klinische diagnose van vaatlijden, samenstelling van de atherosclerotische plaque en de uitkomst van de ziekte. Show less
LCH lesions are characterized by accumulating LCH-cells, which are related to Langerhans and/or Dendritic cells, and the presence of other elements of the immune system. A significant proportion of... Show moreLCH lesions are characterized by accumulating LCH-cells, which are related to Langerhans and/or Dendritic cells, and the presence of other elements of the immune system. A significant proportion of LCH-cells display somatic mutations in proteins that drive the constitutive activation of the MAPK-pathway. Outcome is heterogeneous and unpredictable. The main goal of this thesis was to gain insight to the pathogenesis of Langerhans Cell Histiocytosis (LCH) by studying the genetic and immunologic ‘finger-prints’ of therapy-naive LCH lesions. We found a few biomarkers that could predict the outcome of LCH. These include the expression of a chemokine receptor, CXCR4, on LCH-cells and the degree of lymphoid aggregation within the LCH lesions. We found an ever functionally intact IFN-γ-signalling loop in LCH patients and the presence of activated and regulatory T-cells. However, neither an activated or immunosuppressive environment in LCH lesions was associated with a particular LCH manifestation form or outcome. We found another MAPK-pathway activating mutation in LCH-cells which was sensitive towards the FDA approved BRAF-inhibitor vemurafenib. The research described in this thesis support the concept that LCH lesions should be seen as a ‘cocktail’ of genetically aberrant LCH-cells which accumulate at sites with a mixed immunological background. Show less
The worldwide resurgence of whooping cough (pertussis), even in highly vaccinated populations, demands improved pertussis vaccines. In this thesis a systems vaccinology approach is applied to... Show moreThe worldwide resurgence of whooping cough (pertussis), even in highly vaccinated populations, demands improved pertussis vaccines. In this thesis a systems vaccinology approach is applied to deepen knowledge of the immune responses evoked by different pertussis vaccines and compare this with a Bordetella pertussis infection since the latter induces robust protection. Infection-induced responses in mice conferred sterilizing protection that is caused by systemic immunity but more importantly by mucosal IgA, T-helper (Th)1/Th17 responses, and ‘trained’ innate immune cells in the lungs. An experimental outer membrane vesicle vaccine (omvPV) was compared with the two licensed vaccines, acellular vaccine (aPV), whole-cell vaccine (wPV) as well as a B. pertussis infection. OmvPV evoked a different immunoproteomic profile with respect to antibody levels, antigen specificity, and subclass distribution. Furthermore, omvPV confers equal protection in mice as wPV, but with a lower inflammatory response. In this thesis it is also shown that the immunization route is critical. Although subcutaneous omvPV immunization is effective, pulmonary administration lead to superior protection, comparable to infection-induced immunity and included hallmarks of protection such as pulmonary Th17 cells and mucosal IgA. The molecular and cellular signatures described in this thesis may have an important contribution to enhanced pertussis immunity. Show less
The human herpesvirus Epstein-Barr virus (EBV) is a large DNA virus that infects over 90% of the adult world population. EBV is the causative agent of infectious mononucleosis and EBV infection is... Show moreThe human herpesvirus Epstein-Barr virus (EBV) is a large DNA virus that infects over 90% of the adult world population. EBV is the causative agent of infectious mononucleosis and EBV infection is associated with various malignancies. EBV establishes lifelong infections in immunocompetent hosts. To counteract the host’s immune defence, EBV acquired numerous immune evasion mechanisms. During latency of EBV, viral protein synthesis is limited or absent, making the virus-infected cells virtually invisible to the immune system. Evasion mechanisms of EBV active during primary infection as well as in reactivation are necessary for establishment of latent infection and prolonged replication. Studying viral evasion not only helps to understand EBV, but also the human immune system. Viral molecules interfering with antigen presentation by HLA I and HLA II have been identified previously, but so far, it was unclear how EBV interferes with the lipid antigen-presenting molecule CD1d. The work described in this thesis shows EBV’s mechanism to interfere with cell surface expression of CD1d. Further, a novel immune evasion molecule that obstructs antigen-presentation during the late lytic phase of EBV infection was identified and its working mechanism was unravelled. Understanding viral immune evasion mechanisms may aid in developing therapies for EBV-associated diseases. Show less
