@phdthesis{Xiao2004, author = {Xiao, Zheng}, title = {Blimp-1 Regulates Terminal Differentiation of T Cells}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-10530}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2004}, abstract = {The transcriptional repressor-Blimp-1 terminates differentiation of B lymphocytes as well as myeloid cells. Our data show that Blimp-1 is highly expressed in freshly isolated murine primary T lymphocytes, particularly its minor splice variant. Ectopic expression of Blimp-1 by retroviral transduction neither dramatically altered secretion of IFN-{\~a} or IL-4 nor did it induce the ability to suppress as regulatory T cells. However, induction of Blimp-1 resulted in not only a significant reduction in the production of IL-2 but also an inability to proliferate as well as in the reduced viability. These results demonstrate that Blimp-1 might mark end stages of lineage differentiation in T cells.}, language = {en} } @phdthesis{Toben2005, author = {Toben, Catherine Gisela}, title = {Generation and analysis of transgenic mice expressing ovalbumin as a neo-self antigen under control of the myelin basic protein promoter}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-16708}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2005}, abstract = {In this project two novel murine autoimmune models were to be established in an attempt to further investigate the nervous system disorders of Multiple Sclerosis and Guillain Barr{\´e} Syndrome. Previous experimental autoimmune encephalomyelitis (EAE) and experimental autoimmune neuritis (EAN) models have demonstrated that T cells play a major role in these diseases. Which roles CD4 and CD8 T cells specifically have in the initiation, propagation and termination of an autoimmune nervous system disorder remains controversial. To this end two transgenic mice specifically expressing the neo-antigen (Ag) ovalbumin (OVA) in either the central nervous system (CNS) or peripheral nervous system (PNS) were to be generated. The myelin basic protein (MBP) is a major component of the myelin sheath both within the CNS and the PNS. Therefore the MBP promoter was employed for its distinct regulatory elements to facilitate exclusive CNS or PNS OVA expression. The adoptive transfer of OVA specific MHCI restricted (OT-I) and MHCII restricted (OT-II) TCR Tg T cells extended the OVA Tg mouse model by allowing potentially encephalitogenic T cells to be tracked in vivo. Specificity for the target Ag should enable the dynamic role of antigen specific T cells in neuroinflammatory diseases to be revealed in more detail.}, subject = {Multiple Sklerose}, language = {en} } @phdthesis{Wang2006, author = {Wang, Dapeng}, title = {The mechanism of glucocorticoid induced murine thymocyte and peripheral T cell apoptosis}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-17317}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2006}, abstract = {Glucocordicoide sind kleine lipophile Verbindungen, die viele biologische Effekte verursachen, wenn sie an den intrazellul{\"a}ren Glukokortikoidrezeptor (GR) binden. Dieser wandert wiederum in den Nucleus, um dort direkt oder indirekt die Transkription der Gene zu regulieren. Glukokortikoide sind der Grundstein in der Behandlung f{\"u}r eine Anzahl von h{\"a}matologischen b{\"o}sartigen Erkrankungen, wie Leuk{\"a}mie, Lymphome und Myelome. In der Literatur wird beschrieben, dass Glukokortikoide {\"u}ber die Vermittlung von Apoptose wirken.die Wirkung. Trotz der enormen Fortschritte im Verst{\"a}ndnis des regulierten Zelltodes, ist der genaue Mechanismus, den Glukokortikoide bei der Apoptose vermitteln, unbekannt. Die Daten, die bis jetzt erzielt wurden, deuten stark darauf hin, dass Gentransaktivierung durch den GR f{\"u}r den Beginn der durch Glukokortikoide verursachten Thymozytenapoptose verantwortlich ist. Außerdem wurde gezeigt, dass das multikatalytische Proteasom, einige Mitglieder der BCL2-Familie, {\"A}nderungen im Kalziumfluss sowie Caspasen eine wichtige Rolle in der Durchf{\"u}hrungsphase des durch Glukokortikoide vermittelten Zelltodes spielen Jedoch ist die genaue Reihenfolge dieses Prozesses bisher nicht bekannt. Ein Hauptschwierigkeit der gegenw{\"a}rtigen Diskussion entsteht aus der Tatsache, dass unterschiedliche Zellarten, wie Thymozyten, reife T-Zellen und Lymphomzellen verglichen werden, ohne ihre unterschiedlichen Eigenschaften und Genexpressionsprofile zu beachten. Obwohl angenommen wird, dass Glukokortikoide Apoptose {\"u}ber einen konservierten Mechanismus, wird dies nicht durch irgendwelche Daten unterst{\"u}tzt. In anderen Worten, es ist m{\"o}glich, dass Apoptose in Thymozyten, reifen T-Zellen und Lymphomzellen {\"u}ber unterschiedliche Signalwege vermittelt wid. Wir fragten uns daher, ob ein einzelner durch Glukokoritkoide eingeleiteter Signaltransduktionsweg daf{\"u}r verantwortlich ist, dass Apoptose in allen T-Lamphozytenarten eingeleitet wird, oder ob noch andere Signalwege existieren. Daher verglichen wir die Rolle des Proteasomes, verschiedener Caspasen, des lysosomalen Kompartements und anderer Faktoren in der durch Glukokortikoide induzierten Apoptose in Mausthymozyten und pepripheren T-Zellen sowie T-ALL Lymphomzellen. Unsere Entdeckungen zeigen, dass die Anfangsphase der durch Glukokortikoide induzierten Apoptose unabh{\"a}ngig von der Differenzierungsstadien der Zelle ist. Apoptose wird sowohl in Thymozyten als auch in reifen T-Zellen durch den GR vermittelt und ist von der Gentranskription abh{\"a}ngig. Im Gegensatz dazu unterscheidet sich die Durchf{\"u}hrungsphase erheblich in ihren Anforderungen f{\"u}r eine Anzahl von Signaltransduktionskomponenten zwischen Thymozyten und peripheren T-Zellen. W{\"a}hrend in Thymozyten das Proteasom, die Caspasen 3, 8 und 9 sowie Cathepsin B eine wichtige Rolle in durch Glukokortikoide induzierten Zelltod spielen, sind diese Faktoren f{\"u}r die Induktion des Zell-Todes in peripheren T- Zellen entbehrlich. Im Gegensatz dazu scheinen {\"A}nderungen in der Expression und intrazellul{\"a}ren Lokalisation von Mitgliedern der Bcl-2 Familie nicht zum durch Glukokortikoide induzierten Zellltod beitzutragen, egal um welchen Zelltyp es sich handelt. Wir haben beobachtet, dass eine Behandlung von Thymozyten mit Glukokortikoiden zu einer Aktivierung der lysosomalen Protease Cathepsin B f{\"u}hrt. Dies ist ein essentieller Schritt zur Einleitung von Apoptose durch Glukortikoide und zeigt zum ersten Mal, dass der lysosomale Amplifikationsloop in diesen Prozess involviert ist. Die Analyse des durch Glukokortikoide induzierten Zelltodes in verschiedenen T-ALL Zelllinien deutet darauf hin, dass die durch Glukokortikoide induzierten Signalwege in Thymozyten und allen Lymphonzelllinien aber nicht in peripheren T Zellen {\"u}bereinstimmen. Da die hoch-dosierte Glukokortikoidbehandlung eine wichtige Rolle in der Behandlung von hematologischen b{\"o}sartigen Erkrankungen spielt, k{\"o}nnen unsere Beobachtungen eine Grundlage f{\"u}r eine neue Anti-Krebs-Stragie bilden, die darauf ausgelegt ist, spezifisch Tumorzellen zu eliminieren aber reife T-Zellen unber{\"u}hrt lassen.}, subject = {T-Lymphozyt}, language = {en} } @phdthesis{Hauff2009, author = {Hauff, Cornelia}, title = {Aspects of the mode of action of bispecific T cell engager (BiTE) antibodies}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-48369}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2009}, abstract = {Bispecific T cell engager (BiTE) display a novel design among the class of bispecific antibodies and hold great promise to fight diverse cancers. BiTE molecules consist of two different binding entities derived from two human IgG antibodies connected by a short peptide linker. Their binding arms are directed against the CD3e chain of the T cell receptor on T cells and against an antigen that is specific for (e.g., CD19 for lymphoma in MT103) or over-expressed on (e.g., EpCAM for epithelial cancer in MT110) tumor cells. Without requirement for pre- or co-stimulation, BiTE molecules efficiently redirect CD3+ T cells towards tumor cells expressing the relevant target antigen. Only a BiTE molecule simultaneously bound to both tumor cell and T cell activates the T cell to exert its cytolytic function resulting in tumor cell death. In T cells stimulated with both BiTE and target cells, elevated levels of caspase activation and increased expression of cytotoxic and signaling proteins are observed. These include cytolytic proteins granzyme B and perforin, activation markers CD69 and CD25 and adhesion molecules CD2 and LFA-1. Activated T cells secrete the usual mix of cytokines, among them pro-inflammatory cytokines IFN-g and TNF-a. The membrane of tumor cells expressing the relevant target antigen is perforated during the attack of BiTE-stimulated effector cells as can be concluded from adenylate kinase release from the cytosol of tumor cells. Ca2+-chelator EGTA completely blocked BiTE-mediated activation of caspases and tumor cell lysis. As perforin is strictly Ca2+-dependent, a major role for this pore-forming protein is assumed for the elimination of tumor cells via BiTE-stimulated T cells. Granzyme B and caspases are main players in BiTE-mediated elimination of tumor cells. Inhibitors of granzyme B or caspases reduce or block, respectively the activation of caspases. However, other signals of apoptosis (cleavage of PARP and fragmentation of DNA) were only reduced by granzyme B inhibitor or caspase inhibitor. Most interestingly, the lytic capacity of BiTE molecules was not impaired by granzyme B inhibitor or caspase inhibitor. It seems that there is no requirement for granzyme B and caspases to be present simultaneously. Instead the data presented provide evidence that they can be replaced one at a time by related proteins. Pre-incubation of effector cells with the glucocorticoids dexamethasone or methylprednisolone resulted in markedly decreased secretion of cytokines by T cells yet only a small reduction in the expression of activation markers and adhesion molecules on T cells and specific lysis of tumor cells upon BiTE stimulation. Soluble factors secreted in an undirected manner by BiTE-stimulated T cells do not mediate tumor cell death by themselves. Bystander cells negative for the antigen that is recognized by the BiTE molecule will not be compromised by BiTE activity. The cytokine TGF-b reduced proliferation as well as granzyme B and perforin expression of BiTE-stimulated T cells. Redirected lysis by BiTE-activated T cells was also decreased under the influence of TGF-b, however lysis was still performed at a reasonable rate (72 \% of target cells). TGF-b does not exert a deleterious effect on lytic potential of BiTE-stimulated T cells. The minimal anticipated biological effect level for the BiTE MT110 was determined for the entry of MT110 into phase I clinical studies. Experiments analyzing redirected lysis of tumor cells, expression of activation marker CD25 and cytokine release by T cells revealed a MABEL value of 50 pg/ml for MT110.}, subject = {Antik{\"o}rper}, language = {en} } @article{PilsKoppPetersonetal.2012, author = {Pils, Stefan and Kopp, Kathrin and Peterson, Lisa and Tascon, Julia Delgado and Nyffenegger-Jann, Naja J. and Hauck, Christof R.}, title = {The Adaptor Molecule Nck Localizes the WAVE Complex to Promote Actin Polymerization during CEACAM3-Mediated Phagocytosis of Bacteria}, series = {PLoS One}, volume = {7}, journal = {PLoS One}, number = {3}, doi = {10.1371/journal.pone.0032808}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-131747}, pages = {e32808}, year = {2012}, abstract = {Background: CEACAM3 is a granulocyte receptor mediating the opsonin-independent recognition and phagocytosis of human-restricted CEACAM-binding bacteria. CEACAM3 function depends on an intracellular immunoreceptor tyrosine-based activation motif (ITAM)-like sequence that is tyrosine phosphorylated by Src family kinases upon receptor engagement. The phosphorylated ITAM-like sequence triggers GTP-loading of Rac by directly associating with the guanine nucleotide exchange factor (GEF) Vav. Rac stimulation in turn is critical for actin cytoskeleton rearrangements that generate lamellipodial protrusions and lead to bacterial uptake. Principal Findings: In our present study we provide biochemical and microscopic evidence that the adaptor proteins Nck1 and Nck2, but not CrkL, Grb2 or SLP-76, bind to tyrosine phosphorylated CEACAM3. The association is phosphorylation-dependent and requires the Nck SH2 domain. Overexpression of the isolated Nck1 SH2 domain, RNAi-mediated knock-down of Nck1, or genetic deletion of Nck1 and Nck2 interfere with CEACAM3-mediated bacterial internalization and with the formation of lamellipodial protrusions. Nck is constitutively associated with WAVE2 and directs the actin nucleation promoting WAVE complex to tyrosine phosphorylated CEACAM3. In turn, dominant-negative WAVE2 as well as shRNA-mediated knock-down of WAVE2 or the WAVE-complex component Nap1 reduce internalization of bacteria. Conclusions: Our results provide novel mechanistic insight into CEACAM3-initiated phagocytosis. We suggest that the CEACAM3 ITAM-like sequence is optimized to co-ordinate a minimal set of cellular factors needed to efficiently trigger actin-based lamellipodial protrusions and rapid pathogen engulfment.}, language = {en} } @article{HartungSeufertBergesetal.2012, author = {Hartung, Andreas and Seufert, Florian and Berges, Carsten and Gessner, Viktoria H. and Holzgrabe, Ulrike}, title = {One-Pot Ugi/Aza-Michael Synthesis of Highly Substituted 2,5-Diketopiperazines with Anti-Proliferative Properties}, series = {Molecules}, volume = {17}, journal = {Molecules}, number = {12}, doi = {10.3390/molecules171214685}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-130423}, pages = {14685-14699}, year = {2012}, abstract = {The well-known Ugi reaction of aldehydes with amines, carboxylic acids and isocyanides leads to the formation of acyclic alpha-acylaminocarboxamides. Replacement of the carboxylic acid derivatives with beta-acyl substituted acrylic acids gives access to highly substituted 2,5-diketopiperazines in one single reaction-step without additives or complex reaction procedures. The obtained diketopiperazines show anti-proliferative effects on activated T cells and represent therefore potential candidates for targeting unwanted T cell-mediated immune responses.}, language = {en} } @article{FujiKappEinsele2013, author = {Fuji, Shigeo and Kapp, Markus and Einsele, Hermann}, title = {Monitoring of Pathogen-Specific T-Cell Immune Reconstitution after Allogeneic Hematopoietic Stem Cell Transplantation}, series = {Frontiers in Immunology}, volume = {4}, journal = {Frontiers in Immunology}, number = {276}, doi = {10.3389/fimmu.2013.00276}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-129250}, year = {2013}, abstract = {The clinical outcome after allogeneic hematopoietic stem cell transplantation (HSCT) has been significantly improved during the last decades with regard to the reduction in organ failure, infection, and severe acute graft-versus-host disease. However, severe complications due to infectious diseases are still one of the major causes of morbidity and mortality after allogeneic HSCT, in particular in patients receiving haploidentical HSCT or cord blood transplant due to a slow and often incomplete immune reconstitution. In order to improve the immune control of pathogens without an increased risk of alloreactivity, adoptive immunotherapy using highly enriched pathogen-specificT cells offers a promising approach. In order to identify patients who are at high risk for infectious diseases, several monitoring assays have been developed with potential for the guidance of immunosuppressive drugs and adoptive immunotherapy in clinical practice. In this article, we aim to give a comprehensive overview regarding current developments of T-cell monitoring techniques focusing on T cells against viruses and fungi. In particular, we will focus on rather simple, fast, non-labor-intensive, cellular assays which could be integrated in routine clinical screening approaches.}, language = {en} } @phdthesis{Voegtle2014, author = {V{\"o}gtle, Timo}, title = {Studies on receptor signaling and regulation in platelets and T cells from genetically modified mice}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-97114}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2014}, abstract = {Receptors with tyrosine-based signaling motifs control essential functions of hematopoietic cells, including lymphocytes and platelets. Downstream of the platelet receptor glycoprotein (GP) VI and the T cell receptor (TCR) the immunoreceptor tyrosine-based activation motif (ITAM) initiates a signaling cascade that involves kinases, adapter and effector proteins and finally leads to cellular activation. This thesis summarizes the results of three studies investigating different aspects of receptor signaling and regulation in platelets and T cells. In the first part, the impact of constitutive Ca2+ influx on TCR signaling and T cell physiology was investigated using a transgenic mouse line with a mutation in the Ca2+ sensor stromal interaction molecule 1 (STIM1). The elevated cytoplasmic Ca2+ level resulted in an altered phosphorylation pattern of the key enzyme phospholipase (PL) Cγ1 in response to TCR stimulation, but without affecting its enzymatic activity. Withdrawal of extracellular Ca2+ or inhibition of the phosphatase calcineurin restored the normal phosphorylation pattern. In addition, there was a decrease in the release of Th2-type cytokines interleukin 4, 5 and 13 upon stimulation in vitro. The second part of the thesis deals with the role of the adapter protein growth factor receptor-bound protein 2 (Grb2) in platelets using a megakaryocyte/platelet-specific knockout mouse line. Loss of Grb2 severely impaired signaling of GPVI and C-type lectin-like receptor 2 (CLEC-2), a related hemITAM receptor. This was attributed to defective stabilization of the linker for activation of T cells (LAT) signalosome and resulted in reduced adhesion, aggregation, Ca2+ mobilization and procoagulant activity downstream of (hem)ITAM-coupled receptors in vitro. In contrast, the signaling pathways of G protein-coupled receptors (GPCRs) and the integrin αIIbβ3, which do not utilize the LAT signalosome, were unaffected. In vivo, the defective (hem)ITAM signaling caused prolonged bleeding times, however, thrombus formation was only affected under conditions where GPCR signaling was impaired (upon acetylsalicylic acid treatment). These results establish Grb2 as an important adapter protein in the propagation of GPVI- and CLEC-2-induced signals. Finally, the proteolytic regulation of the immunoreceptor tyrosine-based switch motif (ITSM)-bearing receptor CD84 in platelets was investigated. This study demonstrated that in mice CD84 is cleaved by two distinct and independent proteolytic mechanisms upon platelet activation: shedding of the extracellular part, which is exclusively mediated by a disintegrin and metalloproteinase (ADAM) 10 and cleavage of the intracellular C-terminus by the protease calpain. Finally, the analysis of soluble CD84 levels in the plasma of transgenic mice revealed that shedding of CD84 by ADAM10 occurs constitutively in vivo.}, subject = {Thrombozyt}, language = {en} } @article{AvotadeLiraSchneiderSchaulies2019, author = {Avota, Elita and de Lira, Maria Nathalia and Schneider-Schaulies, Sibylle}, title = {Sphingomyelin breakdown in T cells: role of membrane compartmentalization in T cell signaling and interference by a pathogen}, series = {Frontiers in Cell and Developmental Biology}, volume = {7}, journal = {Frontiers in Cell and Developmental Biology}, number = {152}, issn = {2296-634X}, doi = {10.3389/fcell.2019.00152}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-199168}, year = {2019}, abstract = {Sphingolipids are major components of cellular membranes, and at steady-state level, their metabolic fluxes are tightly controlled. On challenge by external signals, they undergo rapid turnover, which substantially affects the biophysical properties of membrane lipid and protein compartments and, consequently, signaling and morphodynamics. In T cells, external cues translate into formation of membrane microdomains where proximal signaling platforms essential for metabolic reprograming and cytoskeletal reorganization are organized. This review will focus on sphingomyelinases, which mediate sphingomyelin breakdown and ensuing ceramide release that have been implicated in T-cell viability and function. Acting at the sphingomyelin pool at the extrafacial or cytosolic leaflet of cellular membranes, acid and neutral sphingomyelinases organize ceramide-enriched membrane microdomains that regulate T-cell homeostatic activity and, upon stimulation, compartmentalize receptors, membrane proximal signaling complexes, and cytoskeletal dynamics as essential for initiating T-cell motility and interaction with endothelia and antigen-presenting cells. Prominent examples to be discussed in this review include death receptor family members, integrins, CD3, and CD28 and their associated signalosomes. Progress made with regard to experimental tools has greatly aided our understanding of the role of bioactive sphingolipids in T-cell biology at a molecular level and of targets explored by a model pathogen (measles virus) to specifically interfere with their physiological activity.}, language = {en} } @article{EinseleBorghaeiOrlowskietal.2020, author = {Einsele, Hermann and Borghaei, Hossein and Orlowski, Robert Z. and Subklewe, Marion and Roboz, Gail J. and Zugmaier, Gerhard and Kufer, Peter and Iskander, Karim and Kantarjian, Hagop M.}, title = {The BiTE (Bispecific T-Cell Engager) Platform: Development and Future Potential of a Targeted Immuno-Oncology Therapy Across Tumor Types}, series = {Cancer}, volume = {126}, journal = {Cancer}, number = {14}, doi = {10.1002/cncr.32909}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-215426}, pages = {3192 -- 3201}, year = {2020}, abstract = {Immuno-oncology therapies engage the immune system to treat cancer. BiTE (bispecific T-cell engager) technology is a targeted immuno-oncology platform that connects patients' own T cells to malignant cells. The modular nature of BiTE technology facilitates the generation of molecules against tumor-specific antigens, allowing off-the-shelf immuno-oncotherapy. Blinatumomab was the first approved canonical BiTE molecule and targets CD19 surface antigens on B cells, making blinatumomab largely independent of genetic alterations or intracellular escape mechanisms. Additional BiTE molecules in development target other hematologic malignancies (eg, multiple myeloma, acute myeloid leukemia, and B-cell non-Hodgkin lymphoma) and solid tumors (eg, prostate cancer, glioblastoma, gastric cancer, and small-cell lung cancer). BiTE molecules with an extended half-life relative to the canonical BiTE molecules are also being developed. Advances in immuno-oncology made with BiTE technology could substantially improve the treatment of hematologic and solid tumors and offer enhanced activity in combination with other treatments.}, language = {en} }