Erste Schritte zu einem Mausmodell für Epstein-Barr-Virus

EBV ist ätiologisch eng mit verschiedenen malignen Erkrankungen des Menschen verbunden Die meisten Erkenntnisse über die Funktionen viraler Proteine, die z. B. bei der B-Zell-Trans-formation eine Rolle spielen, stammen aus Zellkulturexperimenten, denen allerdings die Komponenten und die Komplexität eines lebenden Organismus fehlen, weswegen ein Tiermodell wünschenswert ist. Eine Möglichkeit nähere Informationen über die Machbarkeit eines Tiermodells zu bekommen, führt über die genetische Manipulation von embryonalen Stammzellen (ES-Zellen) der Maus. Dazu wurde die genetische Information des Epstein-Barr Virus direkt in EBNA1-positive ES-Zellen der Maus einbracht und die Aufrechterhaltung des Gesamtgenoms als extrachromosomales Plasmid nachgewiesen werden. Die ES-Zellen wurden dann in vitro zu B-Zellen differenziert, um den transformierenden Phänotyp dieses Virus in murinen B-Zellen zu analysieren. Sowohl in den ES-Zellen als auch in den in vitro differenzierten B-Zellen wurde eine Expression der Gene LMP1 und LMP2A gefunden, nicht aber eine Expression des Gens EBNA2. Dieses Expressionsmuster ist charakteristisch für die Latenz II des Virus. Die viralen EBNA-Promotoren waren in beiden Zellarten aktiv, aber eine genaue Analyse ergab Hinweise auf Probleme bei der Transkription bzw. bei der mRNA-Prozessierung. Dies ist vermutlich der Grund für das Fehlen einer EBNA2-Genexpression

Restricted Expression of Epstein-Barr Virus Latent Genes in Murine B Cells Derived from Embryonic Stem Cells

Background: Several human malignancies are associated with Epstein-Barr virus (EBV) and more than 95 % of the adult human population carries this virus lifelong. EBV efficiently infects human B cells and persists in this cellular compartment latently. EBV-infected B cells become activated and growth transformed, express a characteristic set of viral latent genes, and acquire the status of proliferating lymphoblastoid cell lines in vitro. Because EBV infects only primate cells, it has not been possible to establish a model of infection in immunocompetent rodents. Such a model would be most desirable in order to study EBV’s pathogenesis and latency in a suitable and amenable host. Methodology/Principal Findings: We stably introduced recombinant EBV genomes into mouse embryonic stem cells and induced their differentiation to B cells in vitro to develop the desired model. In vitro differentiated murine B cells maintained the EBV genomes but expression of viral genes was restricted to the latent membrane proteins (LMPs). In contrast to human B cells, EBV’s nuclear antigens (EBNAs) were not expressed detectably and growth transformed murine B cells did not arise in vitro. Aberrant splicing and premature termination of EBNA mRNAs most likely prevented the expression of EBNA genes required for B-cell transformation. Conclusions/Significance: Our findings indicate that fundamental differences in gene regulation between mouse and ma

Molecular Epidemiology, Clinical Course, and Implementation of Specific Hygiene Measures in Hospitalised Patients with <i>Clostridioides difficile</i> Infection in Brandenburg, Germany

(1) Background: Clostridioides difficile infections (CDI) have increased worldwide, and the disease is one of the most common healthcare-associated infections (HAI). This study aimed to evaluate the molecular epidemiology of C. difficile, the clinical outcome, and the time of initiation of specific hygiene measures in patients with CDI in a large tertiary-care hospital in Brandenburg. (2) Methods: Faecal samples and data from hospitalised patients diagnosed with CDI were analysed from October 2016 to October 2017. The pathogens were isolated, identified as toxigenic C. difficile, and subsequently subtyped using PCR ribotyping and whole genome sequencing (WGS). Data regarding specific hygiene measures for handling CDI patients were collected. (3) Results: 92.1% of cases could be classified as healthcare-associated (HA)-CDI. The recurrence rate within 30 and 90 days after CDI diagnosis was 15.7% and 18.6%, and the mortality rate was 21.4% and 41.4%, respectively. The most frequent ribotypes (RT) were RT027 (31.3%), RT014 (18.2%), and RT005 (14.1%). Analysis of WGS data using cgMLST showed that all RT027 isolates were closely related; they were assigned to two subclusters. Single-room isolation or barrier measures were implemented in 95.7% patients. (4) Conclusions: These data show that RT027 is regionally predominant, thus highlighting the importance of specific hygiene measures to prevent and control CDI and the need to improve molecular surveillance of C. difficile at the local and national level

Ludwig Boltzmann Cluster Oncology (LBC ONC): first 10 years and future perspectives

In 2008 the Ludwig Boltzmann Cluster Oncology (LBC ONC) was established on the basis of two previous Ludwig Boltzmann Institutes working in the field of hematology and cancer research. The general aim of the LBC ONC is to improve treatment of hematopoietic neoplasms by eradicating cancer-initiating and disease-propagating cells, also known as leukemic stem cells (LSC) in the context of leukemia. In a first phase, the LBC ONC characterized the phenotype and molecular aberration profiles of LSC in various malignancies. The LSC phenotypes were established in acute and chronic myeloid leukemia, in acute lymphoblastic leukemia and in chronic lymphocytic leukemia. In addition, the concept of preleukemic (premalignant) neoplastic stem cells (pre-L-NSC) was coined by the LBC ONC and was tested in myelodysplastic syndromes and myeloproliferative neoplasms. Phenotypic characterization of LSC provided a solid basis for their purification and for the characterization of specific target expression profiles. In a second phase, molecular markers and targets were validated. This second phase is ongoing and should result in the development of new diagnostics parameters and novel, more effective, LSC-eradicating, treatment strategies; however, many issues still remain to be solved, such as sub-clonal evolution, LSC niche interactions, immunologic control of LSC, and LSC resistance. In the forthcoming years, the LBC ONC will concentrate on developing LSC-eradicating strategies, with special focus on LSC resistance, precision medicine and translation of LSC-eradicating concepts into clinical application.(VLID)477375

Demokratiebarometer: ein neues Instrument zur Messung von Demokratiequalität

Ziel dieses Artikels ist die Präsentation eines neuen Demokratieindex – des Demokratiebarometers. Das Demokratiebarometer versucht, die konzeptionellen und methodologischen S chwächen bisheriger Demokratiemaße zu überwinden, um so die Qualitätsunterschiede von etablierten Demokratien messen und analysieren zu können. Der Index basiert auf einem ausdifferenzierten Demokratiekonzept, aus dem in mehreren transparenten S chritten die Messindikatoren abgeleitet werden: Aus den drei konstituierenden Prinzipien F reiheit, Gleichheit und Kontrolle werden zunächst neun grundlegende F unktionen deduziert, aus denen dann Komponenten und daraus wiederum Subkomponenten und schließlich Indikatoren abgeleitet werden. Dieses Konzept wird in einem ersten S chritt dargelegt. Danach werden die methodologischen Grundlagen – die Messung und Aggregierung – des Demokratiebarometers erläutert. Die Präsentation erster Resultate sowie die E rgebnisse verschiedener Validitätstests zeigen schließlich die Plausibilität und das Potenzial dieses neuen Messinstruments auf