Depletion of T cells via Inducible Caspase 9 Increases Safety of Adoptive T-Cell Therapy Against Chronic Hepatitis B

T-cell therapy with T cells that are re-directed to hepatitis B virus (HBV)-infected cells by virus-specific receptors is a promising therapeutic approach for treatment of chronic hepatitis B and HBV-associated cancer. Due to the high number of target cells, however, side effects such as cytokine release syndrome or hepatotoxicity may limit safety. A safeguard mechanism, which allows depletion of transferred T cells on demand, would thus be an interesting means to increase confidence in this approach. In this study, T cells were generated by retroviral transduction to express either an HBV-specific chimeric antigen receptor (S-CAR) or T-cell receptor (TCR), and in addition either inducible caspase 9 (iC9) or herpes simplex virus thymidine kinase (HSV-TK) as a safety switch. Real-time cytotoxicity assays using HBV-replicating hepatoma cells as targets revealed that activation of both safety switches stopped cytotoxicity of S-CAR- or TCR-transduced T cells within less than one hour. In vivo, induction of iC9 led to a strong and rapid reduction of transferred S-CAR T cells adoptively transferred into AAV-HBV-infected immune incompetent mice. One to six hours after injection of the iC9 dimerizer, over 90% reduction of S-CAR T cells in the blood and the spleen and of over 99% in the liver was observed, thereby limiting hepatotoxicity and stopping cytokine secretion. Simultaneously, however, the antiviral effect of S-CAR T cells was diminished because remaining S-CAR T cells were mostly non-functional and could not be restimulated with HBsAg. A second induction of iC9 was only able to deplete T cells in the liver. In conclusion, T cells co-expressing iC9 and HBV-specific receptors efficiently recognize and kill HBV-replicating cells. Induction of T-cell death via iC9 proved to be an efficient means to deplete transferred T cells in vitro and in vivo containing unwanted hepatotoxicity

Greed, recklessness and/or dishonesty? An investigation into the micro-regulation and culture of five UK banks between 2004-2009

The author uses a multiple case study approach to examine five UK banks in her paper. The banks are Northern Rock, the Royal Bank of Scotland, Barclays, Lloyds Banking Group and HSBC. The author feels that it is appropriate to use a multiple case study here because it will be interesting to study the micro aspects of regulation and corporate governance of five UK banks. The banks have to comply with the same regulations and laws on a macro level, so it is essential to examine the differences between these banks on a micro level through reviewing annual reports and financial ratios. The case study is longitudinal, spanning across 2004-2009. In accordance to the aims of a case study, the author will describe, understand and explain the effects of the financial crisis 2007 on five UK banks. This case study provides an opportunity to examine the weaknesses and failures of corporate governance of five UK banks at a micro level. The author has two hypotheses at the beginning of the study. First, banks moved from a customer driven culture to sales driven one. Secondly, the banking culture during between 2004-2009 is one of greed, recklessness and dishonesty. With the caveat that one should not make generalisations, there is evidence from the case study that both hypotheses are correct to a certain extent

Methane Emission from Siberian Wet Polygonal Tundra on Multiple Spatial Scales: Process-based Modelling of Methane Fluxes on the Regional Scale, Lena Delta

Uncertainties in the carbon budget of high latitude ecosystems are partly due to difficulties in assessing the spatially and temporally highly variable methane emissions of permafrost soils. CH4 contributes significantly to global warming. Arctic regions are most critically influenced by a changing climate. Modeling approaches are important tools to determine CH4 fluxes of arctic environments. We present two process-based models to calculate methane emission from permafrost soils. Model forcing consists of ECMWF (European Center for Medium-Range Weather Forecasts) meteorological data which are validated against field measurements. Auxiliary input data is derived from satellite imagery and field measurements. A MERIS-FR land classification scheme is used to upscale emissions. Model results are validated using methane flux measurements on the landscape and small scale carried out in 2006 in the Lena Delta (72°N, 126°E) by Alfred Wegener Institute for Polar and Marine Research. The study site is characterized by arctic tundra ecosystems and continuous permafrost

Methane emissions from wet polygonal tundra II: Modelling methane fluxes on the regional scale a case study for the Lena River Delta region

Arctic regions are especially influenced by a warming climate and thus are of high scientific interest. Methane, a highly radiative active trace gas and hence affecting global warming, is produced in permafrost soils and released into the atmosphere. The Lena River Delta, located at the Laptev Sea in northeast Siberia, is characterized by arctic tundra ecosystems and is underlain by continuous permafrost. Modelling methane flux is an important step in determining its source strength in high arctic environments.We present a methodical structure wherein two models are coupled and used to assess methane emissions from permafrost soils in the Lena River Delta on the regional scale. The process-based vegetation model BETHY/DLR (Biosphere Energy Transfer Hydrology Model; Knorr 1997, Wisskirchen 2005) is applied to calculate the net primary productivity (NPP) of high arctic tundra vegetation. NPP is parameterised as a measure for substrate availability and thus an important input parameter for the second model: the process-based methane model (Walter 1998) is subsequently used to explicitly model methane emissions for a given soil column, taking into account thawing permafrost.Model forcing consists of meteorological data, e.g. radiation, air and soil temperature and precipitation, obtained from the European Centre for Medium-Range Weather Forecasts (ECMWF). They are validated by field measurements. Auxiliary input data for both models are derived from satellite-borne remote sensing data. A land use/land classification (LULC) scheme based on multispectral LANDSAT-7 ETM+ data (Schneider 2005) is used to derive information on wetland distribution as well as on vegetation and active layer thickness (ALT). The three parameters are key factors in modelling methane emissions from permafrost affected tundra ecosystems.Various measurements of methane flux on the landscape scale and small scale have been carried out during the entire growing season 2006 in the southern part of the Lena River delta (72°N, 126°E) by Alfred Wegener Institute for Polar and Marine Research (Sachs et al. 2007). The data were used to validate presented model results

New pharmacological strategies to fight enveloped viruses.

Enveloped viruses pose an important health threat because most of the persistent and many emerging viruses are enveloped. In particular, newly emerging viruses create a need to develop broad-spectrum antivirals, which usually are obtained by targeting host cell factors. Persistent viruses have developed efficient strategies to escape host immune control, and treatment options are limited. Targeting host cell factors essential for virus persistence, or immune-based therapies provide alternative approaches. In this review, we therefore focus on recent developments to generate antivirals targeting host cell factors or immune-based therapeutic approaches to fight infections with enveloped viruses

Generating CD4+T cells for the T-cell therapy of HBV infection.

Human adenovirus (HAdV) E1B-55K is a multifunctional regulator of productive viral replication and oncogenic transformation in nonpermissive mammalian cells. These functions depend on E1B-55K's posttranslational modification with the SUMO protein and its binding to HAdV E4orf6. Both early viral proteins recruit specific host factors to form an E3 ubiquitin ligase complex that targets antiviral host substrates for proteasomal degradation. Recently, we reported that the PML-NB associated factor Daxx represses efficient HAdV productive infection and is proteasomally degraded via a SUMO-E1B-55K-dependent, E4orf6-independent pathway, the details of which remained to be established. RNF4, a cellular SUMO-targeted ubiquitin ligase (STUbL), induces ubiquitinylation of specific SUMOy lated proteins and plays an essential role during DNA repair. Here, we show that E1B-55K recruits RNF4 to the insoluble nuclear matrix fraction of the infected cell to support RNF4/Daxx association, promoting Daxx PTM and thus inhibiting this antiviral factor. Removing RNF4 from infected cells using RNA interference resulted in blocking the proper establishment of viral replication centers and significantly diminished viral gene expression. These results provide a model for how HAdV antagonize the antiviral host responses by exploiting the functional capacity of cellular STUbLs. Thus, RNF4 and its STUbL function represent a positive factor during lytic infection and a novel candidate for future therapeutic antiviral intervention strategies.IMPORTANCE Daxx is a PML-NB-associated transcription factor that was recently shown to repress efficient HAdV productive infection. To counteract this antiviral measurement during infection, Daxx is degraded via a novel pathway including viral E1B-55K and host proteasomes. This virus-mediated degradation is independent of the classical HAdV E3 ubiquitin ligase complex, which is essential during viral infection to target other host antiviral substrates. To maintain a productive viral life cycle, HAdV E1B-55K early viral protein inhibits the chromatin-remodeling factor Daxx in a SUMO-dependent manner. In addition, viral E1B-55K protein recruits the STUbL RNF4 and sequesters it into the insoluble fraction of the infected cell. E1B-55K promotes complex formation between RNF4-and E1B-55K-targeted Daxx protein, supporting Daxx posttranslational modification prior to functional inhibition. Hence, RNF4 represents a novel host factor that is beneficial for HAdV gene expression by supporting Daxx counteraction. In this regard, RNF4 and other STUbL proteins might represent novel targets for therapeutic intervention