@phdthesis{Matthes2008, author = {Matthes, Constanze}, title = {Immunmodulation Dendritischer Zellen durch Sekretionsprodukte mesenchymaler Stammzellen mit besonderem Focus auf hCyr61/CCN1}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-28129}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2008}, abstract = {Mesenchymale Stammzellen (MSC) sind starke Suppressoren des Immunsystems. F{\"u}r die immunsupressive Wirkung werden l{\"o}sliche Faktoren propagiert. In der vorliegenden Arbeit wurde untersucht, ob neben den bekannten Sekretionsfaktoren stromaler Stammzellen wie RANK/RANKL/OPG, TNF\&\#945;, IFN\&\#947; und verschiedene Interleukine, andere Sekretionsfaktoren eine immunmodulatorische Wirkung auf monozyt{\"a}re Zellen haben. Als Sekretionsprodukt wurde hCyr61 untersucht, das im {\"U}berstand von mit TNF\&\#945; behandelten humanen fetalen Osteoblasten (hFOB) nachgewiesen worden war. Das zur CCN-Familie geh{\"o}rende Protein hCyr61 ist an der Angiogenese beteiligt, wird im Kallus w{\"a}hrend der Frakturheilung vermehrt exprimiert und hat, wie zwischenzeitlich nachgewiesen wurde, einen deutlichen Effekt auf die Differenzierung endothelialer Vorl{\"a}uferzellen aus monozyt{\"a}ren Zellen. In den hier beschriebenen Experimenten wurden sowohl monozyt{\"a}re Zellen aus peripherem Blut (PBMC), als auch THP1-Zellen auf die Ver{\"a}nderung der CD14-, 80-, 83- und 86- Expression unter Stimulation mit und ohne Il-4, GM-CSF und hCyr61 untersucht. Die Expressions{\"a}nderung wurde mittels konventioneller PCR, real-time PCR und FACS-Analyse untersucht. In allen drei Nachweismethoden zeigte sich ein Verlust typisch monozyt{\"a}rer Marker wie CD14 unter Stimulation mit hCyr61. Der Verlust an CD14 scheint bei PBMC deutlicher als bei THP1-Zellen, was m{\"o}glicherweise durch die oben beschriebene endotheliale Differenzierung erkl{\"a}rt wird. THP1-Zellen befinden sich bereits in einer h{\"o}heren Differenzierungsstufe, sodass sie ihr monozyt{\"a}res Commitment nicht vollst{\"a}ndig verlieren.}, subject = {Immunmodulation}, language = {de} } @phdthesis{Shishkova2008, author = {Shishkova, Yoana}, title = {Investigations of Measles virus regulation on activation and function of antigen presenting cells}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-28283}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2008}, abstract = {Interaction with dendritic cells (DCs) is considered as central to immunosuppression induced by viruses, including measles virus (MV). Commonly, viral infection of DCs abrogates their ability to promote T cell expansion, yet underlying mechanisms at a cellular level are undefined. It appears that MV-WTF infection modulate DCs morphology and dynamic adhesion on extra cellular matrix proteins such as FN or ICAM-1. By morphological criteria, WTF-DCs resembled LPS-DCs, associated with their mature phenotype also adhered less efficiently to the FN or ICAM-1 support. Reduced adhesion could not be explained by a lack of \&\#61538;1-integrin expression or activation. Similarly, MV-DCs strongly resembled LPS-DCs in that levels of focal adhesion kinase phosphorylated at Y397 were high and not further enhanced upon FN ligation. Fascin, a downstream effector of integrin signaling was highly upregulated in LPS-DCs and moderately in WTF-DCs, and differences in its subcellular distribution were not observed between both cell cultures. Apparently, however, fascin associated less efficiently with PKC\&\#61537; in WTF-DCs then in LPS-DCs. In line with findings for murine DCs, high motility of mature human DCs was found to require expression of Rac-GTPases. Human LPS-DCs and more so, DC transfected to express constitutively active Rac1 were the most motile DC-species analysed, confirming that migration of human DC also involved Rac activity. The velocity of WTF-DCs on FN is below that of LPS-DCs, indicating that maturation induced by WTF may be insufficient to completely promote integrin signaling which leads to Rac activation. The organisation of MV-DC/T cell interfaces was consistent with that of functional immune synapses with regard to CD3 clustering, MHC class II surface recruitment and MTOC location. These analyses are based in the selection of stable conjugates. Subsequently, however, neither contacts nor calcium flux can be stabilised and sustained in the majority of MV-DC/T cell conjugates and only promoted abortive T cell activation. Formation of spatially organised IS in T cells requites, prolonged contact durations. Therefore, aberrant distribution patterns of CD3 in these structures, if occurring, are not likely to contribute to the type of contacts predominating for WTF-DC/T cell interactions. It is also likely that transient interactions of less than 2 minutes may if at all, not efficiently support viral transmission to T cells. Transient interactions are typically observed with immature DCs in the absence of antigen, but this is not likely to be relevant in our allogenic system, which includes SA-loaded WTF-DCs. Thus, MV-infected DCs retain activities required for initiating, but not sustaining T cell conjugation and activation. This is partially rescued if surface expression of the MV glycoproteins on DCs is abolished by infection with a recombinant MV encoding VSV G protein instead, indicating that these contribute directly to synapse destabilisation and thereby act as effectors of T cell inhibition.}, subject = {Masern}, language = {en} }