Most lymphomas and leukemias are neo¬plasms of B cells. Due to the many different B cell development stages from which these neoplasms arise, the resulting diseases are quite heterogeneous, which... Show moreMost lymphomas and leukemias are neo¬plasms of B cells. Due to the many different B cell development stages from which these neoplasms arise, the resulting diseases are quite heterogeneous, which amongst other things is manifested in different tumor growth location, proliferation potential and surface antigen repertoire. Neverthe¬less, some population characteristics are found in almost all B cell malignancies as the cell-of-origin is identical. One of these is the cell surface antigen CD20. Originally used as a marker to distinguishing B cells from other lymphocytes, it quickly became a target for immunotherapy. Immuno-therapy is a treatment that makes use of immune system components to fight cancer, in this case by the injection of a monoclonal antibody specifically targeting one protein: CD20. The addition of CD20-targeting an¬tibodies to an anti-tumor treatment allows your immune system to recognize CD20-ex¬pressing B cells (diseased and healthy), and dispose of them. Overall, after several decades of research and therapeutic experience with antibodies targeting CD20, new functional discoveries as well as therapeutic advances are still being made, and CD20 therefore remains a highly attractive and fruitful target for the therapy of B cell malignancies as well as certain B-cell mediated autoimmune diseases. Show less
In this research heavy chain antibody fragments (VHHs) are developed as potential tools for non-invasive in vivo imaging of Alzheimer__s disease (AD) and Cerebral Amyloid Angiopathy (CAA). First... Show moreIn this research heavy chain antibody fragments (VHHs) are developed as potential tools for non-invasive in vivo imaging of Alzheimer__s disease (AD) and Cerebral Amyloid Angiopathy (CAA). First the generation of antibody fragments, directed against A_ is described. VHHs that were selected from different libraries showed differential affinity for different A_ epitopes when used for immunohistochemistry. These observations indicate that the VHHs are the first immunologic probes with the capacity to differentiate between parenchymal and vascular beta amyloid aggregates. Next, in chapter three the VHH are assessed on their ability to cross the blood-brain barrier using an established in vitro blood brain barrier co-culture system. VHH ni3A showed the highest transmigration efficiency of all tested VHHs. This transport is, in part, facilitated by a 3 amino acid substitution in its N-terminal domain. Additional studies indicated that the mechanism of transcellular passage of ni3A is by active transport. The data described in chapter four provides preliminary proof that these VHHs have the capacity to target A_ depositions in vivo. Consequently, the VHHs are promising tools for further development as imaging agents for the differential diagnosis of A_-related neurodegenerative diseases like CAA and AD. Show less
Major advancements in the understanding of the immune system have provided us with the opportunity for rational design of therapeutic immunological interventions. The notion that dendritic cells ... Show moreMajor advancements in the understanding of the immune system have provided us with the opportunity for rational design of therapeutic immunological interventions. The notion that dendritic cells (DC) play a crucial role in the activation of T lymphocytes has made DC biology of central importance for vaccine development. Accordingly, efficient delivery of antigen to DCs is one of main objectives in vaccine development. In this thesis, antibody-mediated antigen targeting is evaluated as a potential antigen delivery strategy for therapeutic vaccination. Complexes of protein antigen and antigen-specific antibodies are natural formulations that bind to Fc__ receptors. Fc__R ligation on DCs leads to efficient uptake, DC maturation and presentation of the antigen to T lymphocytes. Interaction of Ag-Ab complexes with Fc__Rs on DCs provides a link between the humoral and cellular arms of the immune response. This thesis contains an extensive evaluation of Fc__R-mediated antigen delivery to dendritic cells in the context of T lymphocyte-mediated immunotherapy. In addition, it contains a detailed analysis of Fc__R function on DCs and addresses the kinetics of cross-presentation of antigen after Fc__R-mediated uptake. Show less
