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ABSTRACT: Schmallenberg virus (SBV), a novel orthobunyavirus, was discovered in Germany in 2011. In adult ruminants SBV causes mild transient disease, but foetal infection can lead to severe malformations. Owing to its recent discovery, the knowledge about the pathogenesis is limited. In this study, two heifers seroconverted after a previous SBV infection and five SBV antibody-negative calves were subcutaneously inoculated, another two animals received SBV orally and three were kept as controls. In naïve cattle infected subcutaneously viral RNA was detected in serum and blood samples for several days. Seropositive or orally inoculated animals as well as the uninfected controls remained negative throughout the study. Seroconversion was observed only after subcutaneous exposure of the naïve animals to SBV. In lymphocytes from peripheral blood SBV genome was not detected, but the lymphocyte homeostasis in blood was influenced.
Veterinary Microbiology 02/2013; · 3.33 Impact Factor
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ABSTRACT: Hamster polyomavirus (HaPyV) major capsid protein VP1 based chimeric virus-like particles (VLPs) carrying model GP33 CTL epitope derived from Lymphocytic choriomeningitis virus (LCMV) were generated in yeast and examined for their capability to induce CTL response in mice. Chimeric VP1-GP33 VLPs were effectively processed in antigen presenting cells in vitro and in vivo and induced antigen-specific CD8+ T cell proliferation. Mice immunized only once with VP1-GP33 VLPs without adjuvant developed an effective GP33-specific memory T cell response: 70% were fully and 30% partially protected from LCMV infection. Moreover, aggressive growth of tumors expressing GP33 was significantly delayed in these mice in vivo. Therefore, HaPyV VP1-derived VLP harboring CTL epitopes are attractive vaccine candidates for the induction of insert-specific CTL immune response.
Virus Research 08/2011; 163(1):2-10. · 2.94 Impact Factor
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ABSTRACT: A licensed, inactivated vaccine based on a low pathogenic avian influenza virus strain (H5N2) was evaluated in layer hens kept under field conditions during a 2-year period. Vaccine efficacy was investigated by specific antibodies and by challenge-contact experiments using highly pathogenic avian influenza viruses (HPAIV) H5N1. Basic immunization with two applications induced clinical protection. Virus excretion by vaccinated hens was significantly reduced compared to non-vaccinated controls; transmission to non-vaccinated and vaccinated contact birds was not fully interrupted. Vaccination efficacy is influenced by several factors including antigenic relatedness between vaccine and field strains, but also by species, age and type of commercial uses of the host. Limitations and risks of HPAIV vaccination as silent spread of HPAIV and emergence of escape mutants must be considered a priori and appropriate corrective measures have to be installed.
Vaccine 10/2010; 28(42):6832-40. · 3.77 Impact Factor
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ABSTRACT: Infectious laryngotracheitis is an important respiratory disease of chickens that is caused by an alphaherpesvirus [infectious laryngotracheitis virus (ILTV); Gallid herpesvirus 1]. As herpesvirus envelope glycoproteins are main targets of the humoral host immune response, they are of particular interest for development of vaccines, as well as of diagnostic tools. The conserved, N-glycosylated envelope protein gC has been identified as a major surface antigen of ILTV. To study the function of gC, we now isolated a gC-deleted ILTV recombinant as well as a gC rescuant after co-transfection of permissive chicken cells with virion DNA and transfer plasmids containing engineered subgenomic fragments. Like other alphaherpesvirus homologues, ILTV gC proved to be non-essential for replication. ILTV-DeltagC exhibited delayed penetration kinetics and slightly reduced plaque sizes in cultured chicken cells, whereas virus titres were not reduced significantly compared with wild-type or gC-rescued virus. In vivo studies revealed that ILTV-DeltagC is attenuated in chickens. However, infection with high doses of ILTV-DeltagC was still fatal for approximately 20 % of the animals, whereas wild-type or gC-rescued ILTV led to 50 % mortality. Interestingly, innate and specific immune responses against ILTV-DeltagC were not reduced but enhanced, and surviving chickens were protected completely against challenge infection. Furthermore, ILTV-DeltagC might serve as a basis for marker vaccines permitting differentiation between vaccinated and field-virus-infected animals, as gC-specific antibodies could be detected easily in sera of animals infected with wild-type ILTV.
Journal of General Virology 11/2009; 91(Pt 4):847-57. · 3.36 Impact Factor
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Elke Lange,
Donata Kalthoff, Ulrike Blohm,
Jens P Teifke,
Angele Breithaupt,
Christina Maresch,
Elke Starick,
Sasan Fereidouni,
Bernd Hoffmann,
Thomas C Mettenleiter,
Martin Beer,
Thomas W Vahlenkamp
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ABSTRACT: Influenza virus A/H1N1, which is currently causing a pandemic, contains gene segments with ancestors in the North American and Eurasian swine lineages. To get insights into virus replication dynamics, clinical symptoms and virus transmission in pigs, we infected animals intranasally with influenza virus A/Regensburg/D6/09/H1N1. Virus excretion in the inoculated pigs was detected in nasal swabs from 1 day post-infection (p.i.) onwards and the pigs developed generally mild symptoms, including fever, sneezing, nasal discharge and diarrhoea. Contact pigs became infected, shed virus and developed clinical symptoms similar to those in the inoculated animals. Plasma samples of all animals remained negative for virus RNA. Nucleoprotein- and haemagglutinin H1-specific antibodies could be detected by ELISA 7 days p.i. CD4(+) T cells became activated immediately after infection and both CD4(+) and CD8(+) T-cell populations expanded from 3 to 7 days p.i., coinciding with clinical signs. Contact chickens remained uninfected, as judged by the absence of virus excretion, clinical signs and seroconversion.
Journal of General Virology 08/2009; 90(Pt 9):2119-23. · 3.36 Impact Factor
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ABSTRACT: Gene transfer into cells of mammalian, avian or piscine origin by baculoviruses carrying expression cassettes active in vertebrate cells (BacMam method) is an attractive alternative to chemical or physical transfection methods or to the use of vectors originating from viruses of vertebrates. For simultaneous high-level expression of two proteins from recombinant baculoviruses we constructed novel dual expression vectors containing human and murine cytomegalovirus immediate-early enhancer/promoter elements in combination with the baculoviral polyhedrin and p10 promoters for simultaneous expression in vertebrate and insect cells. Transduction of ruminant cells with BacMam viruses containing the green fluorescent protein open reading frame downstream from the respective enhancer/promoter elements revealed that a dual expression cassette combining the murine cytomegalovirus immediate-early 1 sequence with the immediate early enhancer/promoter of human cytomegalovirus yields high levels of protein from both transcription units. Protein expression directed by several cytomegalovirus/baculovirus hybrid promoters proceeded efficiently in insect cells infected with the respective recombinants. However, for expression in vertebrate cells the murine ie1 enhancer/promoter upstream the baculoviral p10 promoter was most efficient.
Journal of virological methods 06/2009; 160(1-2):132-7. · 2.13 Impact Factor
