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Märstetten-Dorf, Switzerland

Ottiger H.-P.,Institute of Virology and Immunoprophylaxis IVI
Biologicals | Year: 2010

The European Pharmacopoeia (Ph. Eur.) requires avian viral vaccines to be free of adventitious agents. Purity testing is an essential quality requirement of immunological veterinary medicinal products (IVMPs) and testing for extraneous agents includes monitoring for many different viruses. Conventional virus detection methods include serology or virus culture, however, molecular tests have become a valid alternative testing method. Nucleic acid testing (NAT) is fast, highly sensitive and has a higher degree of discrimination than conventional approaches. These advantages have led to the development and standardization of polymerase chain reaction (PCR) assays for the detection of avian leucosis virus, avian orthoreovirus, infectious bursal disease virus, infectious bronchitis virus, Newcastle disease virus, infectious laryngotracheitis virus, influenza A virus, Marek's disease virus, turkey rhinotracheitis virus, egg drop syndrome virus, chicken anaemia virus, avian adenovirus and avian encephalomyelitis virus. This paper reviews the development, standardization and assessment of PCR for extraneous agent testing in IVMPs with examples from an Official Medicines Control Laboratory (OMCL). © 2010 The International Association for Biologicals. Source


Zimmer G.,Institute of Virology and Immunoprophylaxis IVI
Viruses | Year: 2010

RNA replicons are derived from either positive- or negative-strand RNA viruses. They represent disabled virus vectors that are not only avirulent, but also unable to revert to virulence. Due to autonomous RNA replication, RNA replicons are able to drive high level, cytosolic expression of recombinant antigens stimulating both the humoral and the cellular branch of the immune system. This review provides an update on the available literature covering influenza virus vaccines based on RNA replicons. The pros and cons of these vaccine strategies will be discussed and future perspectives disclosed. © 2010 by the authors. Source


Baumann A.,Institute of Virology and Immunoprophylaxis IVI | Baumann A.,University of Bern | Mateu E.,Autonomous University of Barcelona | Murtaugh M.P.,University of Minnesota | Summerfield A.,Institute of Virology and Immunoprophylaxis IVI
Veterinary Research | Year: 2013

Porcine reproductive and respiratory syndrome (PRRS) virus (PRRSV) infections are characterized by prolonged viremia and viral shedding consistent with incomplete immunity. Type I interferons (IFN) are essential for mounting efficient antiviral innate and adaptive immune responses, but in a recent study, North American PRRSV genotype 2 isolates did not induce, or even strongly inhibited, IFN-α in plasmacytoid dendritic cells (pDC), representing "professional IFN-α-producing cells". Since inhibition of IFN-α expression might initiate PRRSV pathogenesis, we further characterized PRRSV effects and host modifying factors on IFN-α responses of pDC. Surprisingly, a variety of type 1 and type 2 PRRSV directly stimulated IFN-α secretion by pDC. The effect did not require live virus and was mediated through the TLR7 pathway. Furthermore, both IFN-γ and IL-4 significantly enhanced the pDC production of IFN-α in response to PRRSV exposure. PRRSV inhibition of IFN-α responses from enriched pDC stimulated by CpG oligodeoxynucleotides was weak or absent. VR-2332, the prototype genotype 2 PRRSV, only suppressed the responses by 34%, and the highest level of suppression (51%) was induced by a Chinese highly pathogenic PRRSV isolate. Taken together, these findings demonstrate that pDC respond to PRRSV and suggest that suppressive activities on pDC, if any, are moderate and strain-dependent. Thus, pDC may be a source of systemic IFN-α responses reported in PRRSV-infected animals, further contributing to the puzzling immunopathogenesis of PRRS. © 2013 Baumann et al.; licensee BioMed Central Ltd. Source


Meurens F.,French National Institute for Agricultural Research | Summerfield A.,Institute of Virology and Immunoprophylaxis IVI | Nauwynck H.,Ghent University | Saif L.,Ohio State University | Gerdts V.,University of Saskatchewan
Trends in Microbiology | Year: 2012

An animal model to study human infectious diseases should accurately reproduce the various aspects of disease. Domestic pigs (Sus scrofa domesticus) are closely related to humans in terms of anatomy, genetics and physiology, and represent an excellent animal model to study various microbial infectious diseases. Indeed, experiments in pigs are much more likely to be predictive of therapeutic treatments in humans than experiments in rodents. In this review, we highlight the numerous advantages of the pig model for infectious disease research and vaccine development and document a few examples of human microbial infectious diseases for which the use of pigs as animal models has contributed to the acquisition of new knowledge to improve both animal and human health. © 2011 Elsevier Ltd. Source


Husser L.,Institute of Virology and Immunoprophylaxis IVI | Alves M.P.,University of Bern | Ruggli N.,Institute of Virology and Immunoprophylaxis IVI | Summerfield A.,Institute of Virology and Immunoprophylaxis IVI
Virus Research | Year: 2011

Pathogen recognition receptors are essential for antiviral host immune responses. These specialized receptors detect conserved viral compounds and induce type I interferons (IFN) and pro-inflammatory cytokines. Here we evaluated the contribution of RIG-I, MDA-5 and TLR3 to the recognition of classical swine fever (CSFV), foot-and-mouth disease virus (FMDV), vesicular stomatitis virus (VSV) and influenza A virus (IAV) to IFN-β responses in the porcine epithelial cell line PK-15. To this end, we identified porcine gene specific small interfering RNA sequences and employed a lentivirus (LV)-based system to deliver the corresponding short hairpin RNA. With this, gene knockdown cell lines were created and tested with regard to the knockdown levels over time and following IFN-β stimulation. During several passages of the transduced cells, the expression of both the reporter gene eGFP and the reduced RNA levels of the targeted gene were stable, although the latter was relatively variable. IFN-β induced IFN-responsive genes such as RIG-I, but the levels of the silenced cell line remained reduced compared to the control cells. Based on virus-induced IFN-β mRNA responses, our results indicate that in PK-15 cells FMDV-detection is solely mediated by MDA-5, whereas VSV and IAV are mainly detected by RIG-I with a minor contribution of MDA-5, and CSFV is sensed by MDA-5, RIG-I and TLR3. © 2011 Elsevier B.V. Source

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