546 research outputs found

    Comparison between intratumoral and intravenously administered oncolytic virus therapy with Newcastle disease virus in a xenograft murine model for pancreatic adenocarcinoma

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    Pancreatic ductal adenocarcinoma (PDAC) is characterized by a poor clinical prognosis and is usually a metastatic disease. In the last decades, oncolytic viro-immunotherapy has shown a promise as treatment strategy with encouraging results for a variety of tumors. Newcastle Disease Virus (NDV) is an oncolytic virus which selectively infects and damages tumors either by directly killing tumor cells or by promoting an anti-tumor immune response. Several studies have demonstrated that NDV strains with a multi-basic cleavage site (MBCS) in the fusion protein (F) have increased anti-tumor efficacy upon intratumoral injection in murine tumor models. However, intravenous injections, in which the oncolytic virus spreads systemically, could be more beneficial to treat metastasized PDAC in addition to the primary tumor. In this study, we compared the oncolytic efficacy and safety of intratumoral and intravenous injections with NDV containing an MBCS in F (NDV F3aa) in an immune deficient murine xenograft (BxPC3) model for PDAC. In this model, both intratumoral and intravenous injections with NDV F3aa induced anti-tumor efficacy as measured at 10 days after the first injection. Upon intravenous injection virus was detected in some of the tumors, indicating the systemic spread of the virus. Upon both treatments, mice did not display weight loss or abnormalities and treated mice did not secrete virus to the environment. These data demonstrate that intravenous injections of NDV F3aa can be applicable to treat metastasized cancers in immune deficient hosts without inflicting adverse effects

    Magnetic levitation stabilized by streaming fluid flows

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    We demonstrate that the ubiquitous laboratory magnetic stirrer provides a simple passive method of magnetic levitation, in which the so-called “flea” levitates indefinitely. We study the onset of levitation and quantify the flea’s motion (a combination of vertical oscillation, spinning and “waggling”), finding excellent agreement with a mechanical analytical model. The waggling motion drives recirculating flow, producing a centripetal reaction force that stabilized the flea. Our findings have implications for the locomotion of artificial swimmers and the development of bidirectional microfluidic pumps, and they provide an alternative to sophisticated commercial levitators

    Modified Vaccinia Virus Ankara Preferentially Targets Antigen Presenting Cells in Vitro, Ex Vivo and in Vivo

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    Modified Vaccinia virus Ankara (MVA) is a promising vaccine vector with an excellent safety profile. However, despite extensive pre-clinical and clinical testing, surprisingly little is known about the cellular tropism of MVA, especially in relevant animal species. Here, we performed in vitro, ex vivo and in vivo experiments with recombinant MVA expressing green fluorescent protein (rMVA-GFP). In both human peripheral blood mononuclear cells and mouse lung explants, rMVA-GFP predominantly infected antigen presenting cells. Subsequent in vivo experiments performed in mice, ferrets and non-human primates indicated that preferential targeting of dendritic cells and alveolar macrophages was observed after respiratory administration, although subtle differences were observed between the respective animal species. Following intramuscular injection, rMVA-GFP was detected in interdigitating cells between myocytes, but also in myocytes themselves. These data are important in advancing our understanding of the basis for the immunogenicity of MVA-based vaccines and aid rational vaccine design and delivery strategies

    A Dutch highly pathogenic H5N6 avian influenza virus showed remarkable tropism for extra-respiratory organs and caused severe disease but was not transmissible via air in the ferret model

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    Continued circulation of A/H5N1 influenzaviruses of the A/goose/Guangdong/1/96 lineage in poultry has resulted in the diversificationin multiple genetic and antigenic clades. Since 2009, clade 2.3.4.4 hemagglutinin (HA) containing viruses harboring the internal and neuraminidase (NA) genes of other avian influenzaA viruses have been detected. As a result, various HA-NA combinations, such as A/H5N1, A/H5N2, A/H5N3, A/H5N5, A/H5N6, and A/H5N8 have been identified.As of January 2023, 83 humans have been infected with A/H5N6 viruses, thereby posing an apparent risk for public health. Here, as part of a risk assessment, the in vitro and in vivo characterization of A/H5N6 A/black-headed gull/Netherlands/29/2017 is described. This A/H5N6 virus was not transmitted between ferrets via the air but was of unexpectedly high pathogenicity compared to other described A/H5N6 viruses. The virus replicated and caused severe lesions not only in respiratory tissues but also in multiple extra-respiratory tissues, including brain, liver, pancreas, spleen, lymph nodes, and adrenal gland. Sequence analyses demonstrated that the well-known mammalian adaptation substitution D701N was positively selected in almost all ferrets. In the in vitro experiments, no other known viral phenotypic properties associated with mammalian adaptation or increased pathogenicity were identified.The lack of transmission via the air and the absence of mammalian adaptation markers suggest that the public health risk of this virus is low. The high pathogenicity of this virus in ferrets could not be explained by the known mammalian pathogenicity factors and should be further studied.</p

    Real-time reverse transcriptase PCR assay for detection of human metapneumoviruses from all known genetic lineages

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    The discovery of human metapneumovirus and its implications for respiratory tract disease have emphasized the need for a sensitive, specific, and rapid assay to detect this virus in a clinical setting. It recently became clear that human metapneumovirus can be grouped into at least four genetic lineages. Previously described assays for the detection of human metapneumovirus were developed by using limited sequence information and failed to detect viruses from all four genetic lineages with comparable sensitivities. Here we describe the development and evaluation of a real-time reverse transcriptase PCR assay that detects human metapneumovirus from the four known genetic lineages with equal specificities and sensitivities

    Risk for low pathogenicity avian influenza virus on poultry farms, The Netherlands, 2007–2013

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    Using annual serologic surveillance data from all poultry farms in the Netherlands during 2007–2013, we quantified the risk for the introduction of low pathogenicity avian influenza virus (LPAIV) in different types of poultry production farms and putative spatial-environmental risk factors: distance from poultry farms to clay soil, waterways, and wild waterfowl areas. Outdoor-layer, turkey (meat and breeder), and duck (meat and breeder) farms had a significantly higher risk for LPAIV introduction than did indoor-layer farms. Except for outdoor-layer, all poultry types (i.e., broilers, chicken breeders, ducks, and turkeys) are kept indoors. For all production types, LPAIV risk decreased significantly with increasing distance to medium-sized waterways and with increasing distance to areas with defined wild waterfowl, but only for outdoor-layer and turkey farms. Future research should focus not only on production types but also on distance to waterways and wild bird areas. In addition, settlement of new poultry farms in high-risk areas should be discouraged

    Contemporary human H3N2 influenza a viruses require a low threshold of suitable glycan receptors for efficient infection

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    Recent human H3N2 influenza A viruses (IAV) have evolved to employ elongated glycans terminating in α2,6-linked sialic acid as their receptors. These glycans are displayed in low abundancies by (humanized) Madin-Darby Canine Kidney cells (MDCK and hCK) which are commonly employed to propagate IAV, resulting in low or no viral propagation. Here, we examined whether the overexpression of the glycosyltransferases B3GNT2 and B4GALT1, which are responsible for the elongation of poly-N-acetyllactosamines (LacNAc), would result in improved A/H3N2 propagation. Stable overexpression of B3GNT2 and B4GALT1 in MDCK and hCK cells was achieved by lentiviral integration and subsequent antibiotic selection and confirmed by qPCR and protein mass spectrometry experiments. Flow cytometry and glycan mass spectrometry experiments using the B3GNT2 and/or B4GALT1 knock-in cells demonstrated increased binding of viral hemagglutinins and the presence of a larger number of LacNAc repeating units, especially on hCK-B3GNT2 cells. An increase in the number of glycan receptors did, however, not result in a greater infection efficiency of recent human H3N2 viruses. Based on these results, we propose that H3N2 IAVs require a low number of suitable glycan receptors to infect cells and that an increase in the glycan receptor display above this threshold does not result in improved infection efficiency
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