Studies on Transformations of H-Phosphonates into DNA Analogues Containing P-S or P-C Bonds

In this thesis, mechanistic and synthetic studies on transformations of H-phosphonates into DNA analogues containing P-S or P-C bonds are described. Configurational stability of dinucleoside H-phosphonates and the stereochemical course of their sulfurisation in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) were investigated. In light of these studies, the reported stereoselective sulfurisation of dinucleoside H-phosphonates and benzoylphosphonates in the presence of DBU was proved to be incorrect. Efficient protocols for the synthesis of new nucleotide analogues with non-ionic C-phosphonate internucleotide linkages were developed. The synthesis of dinucleoside 2-pyridylphosphonates was successfully performed by a DBU-promoted reaction of H-phosphonate diesters with N-methoxypyridinium salts. The thio analogues, 2-pyridyl- and 4-pyridyl phosphonothioate diesters, could be obtained by modifying the reactions developed for their oxo counterparts. Dinucleoside 3-pyridylphosphonates were prepared via a palladium(0)-catalysed cross coupling strategy that could be extended also to the synthesis of nucleotide analogues with metal-complexing properties, i.e. terpyridyl- and bipyridylphosphonate derivatives. Oligonucleotides modified with pyridylphosphonate internucleotide linkages have been prepared and preliminary studies on their hybridisation properties and resistance towards enzymatic degradation were performed. Finally, nucleotidic units for the incorporation of pyridylphosphonate groups at the 5’-terminus of oligonucleotides were designed. Condensations of such units with a suitably protected nucleoside afforded after oxidation the expected dinucleoside (3’-5’)-phosphates with pyridylphosphonate monoester functions at the 5’-ends.

Maturation of humoral immune responses : Studies on the effects of antigen type, apoptosis and age

The humoral immune response is dependent on the formation of antibodies. Antibodies are produced by terminally differentiated B cells, plasma cells. Plasma cells are generated either directly from antigen challenged B cells, memory cells or from cells that have undergone the germinal center (GC) reaction. The GC is the main site for class switch, somatic hypermutation and generation of memory cells. Different factors, both internal and external, shape the outcome of the immune response. In this thesis, we have studied a few factors that influence the maturation of the humoral response. We have studied how age affects the response, and we show that responses against thymus dependent antigens (TD) are more affected than responses to thymus independent (TI) antigens, in concordance with the view that the T cell compartment is more affected by age than the B cell compartment. Furthermore, we demonstrate that priming early in life have a big influence on the immune response in the aged individual. Priming with a TI form of the carbohydrate dextran B512 (Dx) induces a reduction of IgG levels in later TD responses against Dx. We have evaluated possible mechanisms for this reduction. The reduction does not seem to be caused by clonal exhaustion or antibody mediated mechanisms. We also showed that the reduced TD response after TI priming can be induced against another molecule than Dx. With the hypothesis that TI antigens induce a plasma cell biased maturation of the responding B cells, we examined the presence of Blimp-1, a master regulator of plasma cell differentiation, in GCs induced by TD and TI antigen. Blimp-1 was found earlier in GCs induced by TI antigen and the staining intensity in these GCs was stronger than in TD antigen induced GCs, indicating that plasma cells might be continuously recruited from these GCs. B cells undergoing the GC reaction are thought to be under a strict selection pressure that removes cells with low affinity for the antigen and also cells that have acquired self-reactivity. We investigated the effect of apoptotic deficiencies on the accumulation of somatic mutations in GC B cells. In mice lacking the death receptor Fas, lpr mice, the frequency of mutations was increased but the pattern of the mutations did not differ from wild type mice. In contrast, mice over-expressing the anti-apoptotic protein Bcl-2, had a lowered frequency of mutations and the mutations introduced had other characteristics.

E-Government Collaboration in the Swedish Public Sector : Multiple Studies on Collaboration Facilitators and Collaboration Modes

Collaboration in the public sector is imperative to achieve e-government objectives such as improved efficiency and effectiveness of public administration and improved quality of public services. Collaboration across organizational and institutional boundaries requires public organizations to share e-government systems and services through for instance, interoperable information technology and processes. Demands on public organizations to become more open also require that public organizations adopt new collaborative approaches for inviting and engaging citizens in governmental activities. E-government related collaboration in the public sector is challenging, however, and collaboration initiatives often fail. Public organizations need to learn how to collaborate since forms of e-government collaboration and expected outcomes are mostly unknown. How public organizations can collaborate and the expected outcomes are thus investigated in this thesis by studying multiple collaboration cases on the acquisition and implementation of a particular e-government investment (digital archive). This thesis also investigates how e-government collaboration can be facilitated through artifacts. It is done through a case study, where objects that cross boundaries between collaborating communities in the public sector are studied, and by designing a configurable process model integrating several processes for social services. By using design science, this thesis also investigates how an m-government solution that facilitates collaboration between citizens and public organizations can be designed. The thesis contributes to literature through describing five different modes of interorganizational collaboration in the public sector and the expected benefits from each mode. It also contributes with an instantiation of a configurable process model supporting three open social e-services and with evidence of how it can facilitate collaboration. This thesis further describes how boundary objects facilitate collaboration between different communities in an open government design initiative. It contributes with a designed mobile government solution, thereby providing proof of concept and initial design implications for enabling collaboration with citizens through citizen sourcing (outsourcing a governmental activity to citizens through an open call). This thesis also identifies research streams within e-government collaboration research through a literature review and the thesis contributions are related to the identified research streams. This thesis gives directions for future research by suggesting that future research should focus further on understanding e-government collaboration and how information and communication technology can facilitate collaboration in the public sector. It is suggested that further research should investigate m-government solutions to form design theories. Future research should also examine how value can be co-created in e-government collaboration.