TY  - THES
A1  - Eichler, Lars
T1  - Effects of desialyation on TCR-cross-linking and antigen sensitivity of CD8 positive T lymphocytes
T1  - Effekte von Neuraminidase auf TCR-cross-linking und Antigensensitivität von CD 8 positiven T Lymphozyten
N2  - The featured experiments focus on changes in T cell membrane glycosylation as a possible means of controlling TCR cross-linking. Taking the long known fact that activated T cells show decreased levels of surface sialic acid as a starting point, differences in ligand binding and cellular reaction upon in vitro stimulation were investigated in naïve, activated and enzymatically desialyated CD8+, 2C TCR transgenic mouse lymphocytes. To detect differences in ligand binding lymphocytes were incubated with various concentrations of fluorescently labeled, soluble MHC/Ig fusion proteins until equilibrium was reached. Without previous washing, cells were analyzed by flow cytometry, determined MCF values were normalized to the plateau and fit to a mathematical model of equilibrium binding of divalent ligands to monomorphic receptors (Perelson 1984). Parameters derived from the model fit of binding data show, that neuraminidase treatment of T cells was sufficient to mimic a partially activated phenotype, showing enhanced TCR cross-linking. Enhanced TCR cross-linking was found to be dependent on the presence of CD8, as neuraminidase treatment of DN cells lead to decreased cross-linking. To elucidate the physiological relevance of desialyation induced increases in TCR cross-linking early tyrosine phosphorylation events and proliferative response upon in vitro stimulation of T cells were investigated. Both were found enhanced in neuraminidase treated cells, as compared to native cells. In conclusion the featured experiments suggest a role of surface sialic acid in controlling TCR cross-linking on naïve and activated T cells.
N2  - Die vorliegenden Experimente zeigen einen Effekt von Neuraminidaseverdauung auf das Bindungsverhalten des T-Zell-Rezeptors der CD8 positiven T-Zelle gegenüber ihrem MHC I Liganden. In vitro Bindungsexperimente, Phosphorylierungs- und Proliferationsassays zeigen, dass Entfernung von Sialylsäure auf T-Lymphozyten einen Phänotyp erzeugt, der dem einer aktivierten T Zelle gleicht. Ein mögliches Schlüsselmolekül für den beobachteten Neuraminidase-Effekt stellt "CD8" dar.
KW  - T Lymphozyt
KW  - CD 8
KW  - Sialylsäure
KW  - TCR
KW  - TCR
KW  - sialic acid
KW  - cross-linking
Y1  - 2005
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-19391
ER  - 
TY  - JOUR
A1  - Vogelsang, Anna
A1  - Eichler, Susann
A1  - Huntemann, Niklas
A1  - Masanneck, Lars
A1  - Böhnlein, Hannes
A1  - Schüngel, Lisa
A1  - Willison, Alice
A1  - Loser, Karin
A1  - Nieswandt, Bernhard
A1  - Kehrel, Beate E.
A1  - Zarbock, Alexander
A1  - Göbel, Kerstin
A1  - Meuth, Sven G.
T1  - Platelet inhibition by low-dose acetylsalicylic acid reduces neuroinflammation in an animal model of multiple sclerosis
JF  - International Journal of Molecular Sciences
N2  - Aside from the established immune-mediated etiology of multiple sclerosis (MS), compelling evidence implicates platelets as important players in disease pathogenesis. Specifically, numerous studies have highlighted that activated platelets promote the central nervous system (CNS)-directed adaptive immune response early in the disease course. Platelets, therefore, present a novel opportunity for modulating the neuroinflammatory process that characterizes MS. We hypothesized that the well-known antiplatelet agent acetylsalicylic acid (ASA) could inhibit neuroinflammation by affecting platelets if applied at low-dose and investigated its effect during experimental autoimmune encephalomyelitis (EAE) as a model to study MS. We found that oral administration of low-dose ASA alleviates symptoms of EAE accompanied by reduced inflammatory infiltrates and less extensive demyelination. Remarkably, the percentage of CNS-infiltrated CD4\(^+\) T cells, the major drivers of neuroinflammation, was decreased to 40.98 ± 3.28% in ASA-treated mice compared to 56.11 ± 1.46% in control animals at the disease maximum as revealed by flow cytometry. More interestingly, plasma levels of thromboxane A\(_2\) were decreased, while concentrations of platelet factor 4 and glycoprotein VI were not affected by low-dose ASA treatment. Overall, we demonstrate that low-dose ASA could ameliorate the platelet-dependent neuroinflammatory response in vivo, thus indicating a potential treatment approach for MS.
KW  - acetylsalicylic acid
KW  - experimental autoimmune encephalomyelitis
KW  - platelets
KW  - multiple sclerosis
KW  - thromboxane
KW  - glycoprotein VI
KW  - platelet factor 4
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-284535
SN  - 1422-0067
VL  - 22
IS  - 18
ER  -