Publications by authors named "Matthias Schweizer"

61 Publications

Zinc accelerates respiratory burst termination in human PMN.

Redox Biol 2021 Sep 17;47:102133. Epub 2021 Sep 17.

Center of Physiology, Pathophysiology and Biophysics, Paracelsus Medical University, Nuremberg, Germany; Center of Physiology, Pathophysiology and Biophysics, Paracelsus Medical University, Salzburg, Austria. Electronic address:

The respiratory burst of phagocytes is essential for human survival. Innate immune defence against pathogens relies strongly on reactive oxygen species (ROS) production by the NADPH oxidase (NOX2). ROS kill pathogens while the translocation of electrons across the plasma membrane via NOX2 depolarizes the cell. Simultaneously, protons are released into the cytosol. Here, we compare freshly isolated human polymorphonuclear leukocytes (PMN) to the granulocytes-like cell line PLB 985. We are recording ROS production while inhibiting the charge compensating and pH regulating voltage-gated proton channel (H1). The data suggests that human PMN and the PLB 985 generate ROS via a general mechanism, consistent of NOX2 and H1. Additionally, we advanced a mathematical model based on the biophysical properties of NOX2 and H1. Our results strongly suggest the essential interconnection of H1 and NOX2 during the respiratory burst of phagocytes. Zinc chelation during the time course of the experiments postulates that zinc leads to an irreversible termination of the respiratory burst over time. Flow cytometry shows cell death triggered by high zinc concentrations and PMA. Our data might help to elucidate the complex interaction of proteins during the respiratory burst and contribute to decipher its termination.
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http://dx.doi.org/10.1016/j.redox.2021.102133DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8476447PMC
September 2021

Eradication of Bovine Viral Diarrhoea (BVD) in Cattle in Switzerland: Lessons Taught by the Complex Biology of the Virus.

Front Vet Sci 2021 7;8:702730. Epub 2021 Sep 7.

Federal Food Safety and Veterinary Office (FSVO), Bern, Switzerland.

Bovine viral diarrhoea virus (BVDV) and related ruminant pestiviruses occur worldwide and cause considerable economic losses in livestock and severely impair animal welfare. Switzerland started a national mandatory control programme in 2008 aiming to eradicate BVD from the Swiss cattle population. The peculiar biology of pestiviruses with the birth of persistently infected (PI) animals upon infection in addition to transient infection of naïve animals requires vertical and horizontal transmission to be taken into account. Initially, every animal was tested for PI within the first year, followed by testing for the presence of virus in all newborn calves for the next four years. Prevalence of calves being born PI thus diminished substantially from around 1.4% to <0.02%, which enabled broad testing for the virus to be abandoned and switching to economically more favourable serological surveillance with vaccination being prohibited. By the end of 2020, more than 99.5% of all cattle farms in Switzerland were free of BVDV but eliminating the last remaining PI animals turned out to be a tougher nut to crack. In this review, we describe the Swiss BVD eradication scheme and the hurdles that were encountered and still remain during the implementation of the programme. The main challenge is to rapidly identify the source of infection in case of a positive result during antibody surveillance, and to efficiently protect the cattle population from re-infection, particularly in light of the endemic presence of the related pestivirus border disease virus (BDV) in sheep. As a consequence of these measures, complete eradication will (hopefully) soon be achieved, and the final step will then be the continuous documentation of freedom of disease.
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http://dx.doi.org/10.3389/fvets.2021.702730DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8452978PMC
September 2021

Positively Charged Amino Acids in the Pestiviral E Control Cell Entry, Endoribonuclease Activity and Innate Immune Evasion.

Viruses 2021 Aug 10;13(8). Epub 2021 Aug 10.

Institute of Virology and Immunology (IVI), CH-3001 Bern, Switzerland.

The genus , family , includes four economically important viruses of livestock, i.e., bovine viral diarrhea virus-1 (BVDV-1) and -2 (BVDV-2), border disease virus (BDV) and classical swine fever virus (CSFV). E and N, both expressed uniquely by pestiviruses, counteract the host's innate immune defense by interfering with the induction of interferon (IFN) synthesis. The structural envelope protein E also exists in a soluble form and, by its endoribonuclease activity, degrades immunostimulatory RNA prior to their activation of pattern recognition receptors. Here, we show that at least three out of four positively-charged residues in the C-terminal glycosaminoglycan (GAG)-binding site of BVDV-E are required for efficient cell entry, and that a positively charged region more upstream is not involved in cell entry but rather in RNA-binding. Moreover, the C-terminal domain on its own determines intracellular targeting, as GFP fused to the C-terminal amino acids of E was found at the same compartments as wt E. In summary, RNase activity and uptake into cells are both required for E to act as an IFN antagonist, and the C-terminal amphipathic helix containing the GAG-binding site determines the efficiency of cell entry and its intracellular localization.
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http://dx.doi.org/10.3390/v13081581DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8402660PMC
August 2021

An outbreak of abortions, stillbirths and malformations in a Spanish sheep flock associated with a bovine viral diarrhoea virus 2-contaminated orf vaccine.

Transbound Emerg Dis 2021 Mar 20;68(2):233-239. Epub 2020 May 20.

Department of Animal Pathology, University of Zaragoza, Zaragoza, Spain.

Bovine viral diarrhoea virus (BVDV) is a pestivirus that affects both cattle and sheep, causing an array of clinical signs, which include abortions and malformations in the offspring. Manufacturing of modified live virus (MLV) vaccines often includes the use of bovine-derived products, which implies a risk of contamination with viable BVDV. Recently, the circulation of a specific strain of BVDV 2b among Spanish sheep flocks, associated with outbreaks of abortions and malformations, and whose origin was not determined, has been observed. On February 2018, a MLV orf vaccine was applied to a 1,600 highly prolific sheep flock in the Northeast of Spain that included 550 pregnant ewes. In May 2018, during the lambing season, an unusual high rate (72.7%) of abortions, stillbirths, congenital malformations and neurological signs in the offspring was observed. It was estimated that about 1,000 lambs were lost. Three 1- to 3-day-old affected lambs and a sealed vial of the applied vaccine were studied. Lambs showed variable degrees of central nervous system malformations and presence of pestiviral antigen in the brain. Molecular studies demonstrated the presence of exactly the same BVDV 2b in the tissues of the three lambs and in the orf vaccine, thus pointing to a pestivirus contamination in the applied vaccine as the cause of the outbreak. Interestingly, sequencing at the 5'-untranslated region-(UTR) of the contaminating virus showed a complete match with the virus described in the previously reported outbreaks in Spain, thus indicating that the same contaminated vaccine could have also played a role in those cases. This communication provides a clear example of the effects of the application of this contaminated product in a sheep flock. The information presented here can be of interest in putative future cases of suspected circulation of this or other BVDV strains in ruminants.
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http://dx.doi.org/10.1111/tbed.13619DOI Listing
March 2021

Long-Term Circulation of Atypical Porcine Pestivirus (APPV) within Switzerland.

Viruses 2019 07 17;11(7). Epub 2019 Jul 17.

Institute of Virology and Immunology (IVI), 3001 Bern and 3147 Mittelhäusern, Switzerland.

In 2015, a new pestivirus was described in pig sera in the United States. This new "atypical porcine pestivirus" (APPV) was later associated with congenital tremor (CT) in newborn piglets. The virus appears to be distributed worldwide, but the limited knowledge of virus diversity and the use of various diagnostic tests prevent direct comparisons. Therefore, we developed an APPV-specific real-time RT-PCR assay in the 5'UTR of the viral genome to investigate both retro- and prospectively the strains present in Switzerland and their prevalence in domestic pigs. Overall, 1080 sera obtained between 1986 and 2018 were analyzed, revealing a virus prevalence of approximately 13% in pigs for slaughter, whereas it was less than 1% in breeding pigs. In the prospective study, APPV was also detected in piglets displaying CT. None of the samples could detect the Linda virus, which is another new pestivirus recently reported in Austria. Sequencing and phylogenetic analysis revealed a broad diversity of APP viruses in Switzerland that are considerably distinct from sequences reported from other isolates in Europe and overseas. This study indicates that APPV has already been widely circulating in Switzerland for many years, mainly in young animals, with 1986 being the earliest report of APPV worldwide.
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http://dx.doi.org/10.3390/v11070653DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6669711PMC
July 2019

Border disease in cattle.

Vet J 2019 Apr 1;246:12-20. Epub 2019 Feb 1.

Institute for Virology and Immunology, Länggass-Strasse 122, 3001 Bern, Switzerland; Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, Länggass-Strasse 122, 3001 Bern, Switzerland.

Within the family Flaviviridae, viruses within the genus Pestivirus, such as Border disease virus (BDV) of sheep, can cause great economic losses in farm animals. Originally, the taxonomic classification of pestiviruses was based on the host species they were isolated from, but today, it is known that many pestiviruses exhibit a broad species tropism. This review provides an overview of BDV infection in cattle. The clinical, hematological and pathological-anatomical findings in bovines that were transiently or persistently infected with BDV largely resemble those in cattle infected with the closely related pestivirus bovine viral diarrhoea virus (BVDV). Accordingly, the diagnosis of BDV infection can be challenging, as it must be differentiated from various pestiviruses in cattle. The latter is very relevant in countries with control programs to eradicate BVDV in Bovidae, as in most circumstances, pestivirus infections in sheep, which act as reservoir for BDV, are not included in the eradication scheme. Interspecies transmission of BDV between sheep and cattle occurs regularly, but BDV in cattle appears to be of minor general importance. Nevertheless, BDV outbreaks at farm or local level can be very costly.
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http://dx.doi.org/10.1016/j.tvjl.2019.01.006DOI Listing
April 2019

Bacterial and viral pathogen-associated molecular patterns induce divergent early transcriptomic landscapes in a bovine macrophage cell line.

BMC Genomics 2019 Jan 8;20(1):15. Epub 2019 Jan 8.

Institute of Virology and Immunology, Federal Food Safety and Veterinary Office FSVO, Bern, Switzerland.

Background: Pathogens stimulate immune functions of macrophages. Macrophages are a key sentinel cell regulating the response to pathogenic ligands and orchestrating the direction of the immune response. Our study aimed at investigating the early transcriptomic changes of bovine macrophages (Bomacs) in response to stimulation with CpG DNA or polyI:C, representing bacterial and viral ligands respectively, and performed transcriptomics by RNA sequencing (RNASeq). KEGG, GO and IPA analytical tools were used to reconstruct pathways, networks and to map out molecular and cellular functions of differentially expressed genes (DE) in stimulated cells.

Results: A one-way ANOVA analysis of RNASeq data revealed significant differences between the CpG DNA and polyI:C-stimulated Bomac. Of the 13,740 genes mapped to the bovine genome, 2245 had p-value ≤0.05, deemed as DE. At 6 h post stimulation of Bomac, poly(I:C) induced a very different transcriptomic profile from that induced by CpG DNA. Whereas, 347 genes were upregulated and 210 downregulated in response to CpG DNA, poly(I:C) upregulated 761 genes and downregulated 414 genes. The topmost DE genes in poly(I:C)-stimulated cells had thousand-fold changes with highly significant p-values, whereas in CpG DNA stimulated cells had 2-5-fold changes with less stringent p-values. The highest DE genes in both stimulations belonged to the TNF superfamily, TNFSF18 (CpG) and TNFSF10 (poly(I:C)) and in both cases the lowest downregulated gene was CYP1A1. CpG DNA highly induced canonical pathways that are unrelated to immune response in Bomac. CpG DNA influenced expression of genes involved in molecular and cellular functions in free radical scavenging. By contrast, poly(I:C) highly induced exclusively canonical pathways directly related to antiviral immune functions mediated by interferon signalling genes. The transcriptomic profile after poly(I:C)-stimulation was consistent with induction of TLR3 signalling.

Conclusion: CpG DNA and poly(I:C) induce different early transcriptional landscapes in Bomac, but each is suited to a specific function of macrophages during interaction with pathogens. Poly(I:C) influenced antiviral response genes, whereas CpG DNA influenced genes important for phagocytic processes. Poly(I:C) was more potent in setting the inflammatory landscape desirable for an efficient immune response against virus infection.
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http://dx.doi.org/10.1186/s12864-018-5411-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6323673PMC
January 2019

Traces of history conserved over 600 years in the geographic distribution of genetic variants of an RNA virus: Bovine viral diarrhea virus in Switzerland.

PLoS One 2018 5;13(12):e0207604. Epub 2018 Dec 5.

Institute of Virology and Immunology, Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, Bern, Switzerland.

The first records of smallpox and rabies date back thousands of years and foot-and-mouth disease in cattle was described in the 16th century. These diseases stood out by their distinct signs, dramatic way of transmission from rabid dogs to humans, and sudden appearance in cattle herds. By contrast, infectious diseases that show variable signs and affect few individuals were identified only much later. Bovine viral diarrhea (BVD), endemic in cattle worldwide, was first described in 1946, together with the eponymous RNA virus as its cause. There is general agreement that BVD was not newly emerging at that time, but its history remains unknown. A search for associations between the nucleotide sequences of over 7,000 BVD viral strains obtained during a national campaign to eradicate BVD and features common to the hosts of these strains enabled us to trace back in time the presence of BVD in the Swiss cattle population. We found that animals of the two major traditional cattle breeds, Fleckvieh and Swiss Brown, were infected with strains of only four different subgenotypes of BVDV-1. The history of these cattle breeds and the events that determined the current distribution of the two populations are well documented. Specifically, Fleckvieh originates from the Bernese and Swiss Brown from the central Alps. The spread to their current geographic distribution was determined by historic events during a major expansion of the Swiss Confederation during the 15th and 16th centuries. The association of the two cattle populations with different BVD viral subgenotypes may have been preserved by a lack of cattle imports, trade barriers within the country, and unique virus-host interactions. The congruent traces of history in the distribution of the two cattle breeds and distinct viral subgenotypes suggests that BVD may have been endemic in Switzerland for at least 600 years.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0207604PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6281212PMC
May 2019

Global knowledge gaps in the prevention and control of bovine viral diarrhoea (BVD) virus.

Transbound Emerg Dis 2019 Mar 28;66(2):640-652. Epub 2018 Nov 28.

EpiCentre, School of Veterinary Science, Massey University, Palmerston North, New Zealand.

The significant economic impacts of bovine viral diarrhoea (BVD) virus have prompted many countries worldwide to embark on regional or national BVD eradication programmes. Unlike other infectious diseases, BVD control is highly feasible in cattle production systems because the pathogenesis is well understood and there are effective tools to break the disease transmission cycle at the farm and industry levels. Coordinated control approaches typically involve directly testing populations for virus or serological screening of cattle herds to identify those with recent exposure to BVD, testing individual animals within affected herds to identify and eliminate persistently infected (PI) cattle, and implementing biosecurity measures such as double-fencing shared farm boundaries, vaccinating susceptible breeding cattle, improving visitor and equipment hygiene practices, and maintaining closed herds to prevent further disease transmission. As highlighted by the recent DISCONTOOLS review conducted by a panel of internationally recognized experts, knowledge gaps in the control measures are primarily centred around the practical application of existing tools rather than the need for creation of new tools. Further research is required to: (a) determine the most cost effective and socially acceptable means of applying BVD control measures in different cattle production systems; (b) identify the most effective ways to build widespread support for implementing BVD control measures from the bottom-up through farmer engagement and from the top-down through national policy; and (c) to develop strategies to prevent the reintroduction of BVD into disease-free regions by managing the risks associated with the movements of animals, personnel and equipment. Stronger collaboration between epidemiologists, economists and social scientists will be essential for progressing efforts to eradicate BVD from more countries worldwide.
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http://dx.doi.org/10.1111/tbed.13068DOI Listing
March 2019

The Small-Compound Inhibitor K22 Displays Broad Antiviral Activity against Different Members of the Family Flaviviridae and Offers Potential as a Panviral Inhibitor.

Antimicrob Agents Chemother 2018 11 24;62(11). Epub 2018 Oct 24.

Institute of Virology and Immunology, Bern and Mittelhäusern, Switzerland

The virus family encompasses several viruses, including (re)emerging viruses which cause widespread morbidity and mortality throughout the world. Members of this virus family are positive-strand RNA viruses and replicate their genome in close association with reorganized intracellular host cell membrane compartments. This evolutionarily conserved strategy facilitates efficient viral genome replication and contributes to evasion from host cell cytosolic defense mechanisms. We have previously described the identification of a small-compound inhibitor, K22, which exerts a potent antiviral activity against a broad range of coronaviruses by targeting membrane-bound viral RNA replication. To analyze the antiviral spectrum of this inhibitor, we assessed the inhibitory potential of K22 against several members of the family, including the reemerging Zika virus (ZIKV). We show that ZIKV is strongly affected by K22. Time-of-addition experiments revealed that K22 acts during a postentry phase of the ZIKV life cycle, and combination regimens of K22 together with ribavirin (RBV) or interferon alpha (IFN-α) further increased the extent of viral inhibition. Ultrastructural electron microscopy studies revealed severe alterations of ZIKV-induced intracellular replication compartments upon infection of K22-treated cells. Importantly, the antiviral activity of K22 was demonstrated against several other members of the family. It is tempting to speculate that K22 exerts its broad antiviral activity against several positive-strand RNA viruses via a similar mechanism and thereby represents an attractive candidate for development as a panviral inhibitor.
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http://dx.doi.org/10.1128/AAC.01206-18DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6201103PMC
November 2018

Correction to: Insemination with border disease virus-infected semen results in seroconversion in cows but not persistent infection in fetuses.

BMC Vet Res 2018 06 11;14(1):182. Epub 2018 Jun 11.

Institute for Virology and Immunology, and Department of Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, Bern, Switzerland.

The original article [1] contained an error whereby a co-author, Sarah Züblin had their name displayed incorrectly. This error has now been corrected.
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http://dx.doi.org/10.1186/s12917-018-1497-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5996560PMC
June 2018

Homodimerisation-independent cleavage of dsRNA by a pestiviral nicking endoribonuclease.

Sci Rep 2018 05 29;8(1):8226. Epub 2018 May 29.

Institute of Virology and Immunology, Laenggass-Str. 122, CH-3001, Bern, Switzerland.

The glycoprotein E plays a central role in the biology of the pestivirus bovine viral diarrhea virus (BVDV). This soluble endonuclease mediates the escape from an interferon (IFN) response in the infected fetus, thereby permitting the establishment of persistent infection. Viral single-stranded (ss) and double-stranded (ds) RNA act as potent IFN inducing signals and we previously showed that E efficiently cleaves these substrates, thereby inhibiting an IFN response that is crucial for successful fetal infection. Considering that a large variety of RNases and DNases require dimerisation to cleave double-stranded substrates, the activity of E against dsRNA was postulated to depend on homodimer formation mediated by disulfide bonds involving residue Cys171. Here, we show that monomeric E is equally able to cleave dsRNA and to inhibit dsRNA-induced IFN synthesis as the wild-type form. Furthermore, both forms were able to degrade RNA within a DNA/RNA- as well as within a methylated RNA/RNA-hybrid, with the DNA and the methylated RNA strand being resistant to degradation. These results support our model that E acts as 'nicking endoribonuclease' degrading ssRNA within double-stranded substrates. This efficiently prevents the activation of IFN and helps to maintain a state of innate immunotolerance in persistently infected animals.
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http://dx.doi.org/10.1038/s41598-018-26557-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5974291PMC
May 2018

Broadband polarized emission from P(NDI2OD-T2) polymer.

J Phys Condens Matter 2018 Jul 18;30(26):265101. Epub 2018 May 18.

Department of Physics and Astronomy, University of Alabama, Tuscaloosa, AL, United States of America. Center for Information Technology (MINT), University of Alabama, Tuscaloosa, AL, United States of America.

We investigate the P(NDI2OD-T2) photophysical properties via absorbance and fluorescence spectroscopy, in association with the experimental approach baptized Stokes Spectroscopy, which provides valuable material information through the acquisition and analysis of the fluorescence polarization degree. By changing solvents and using different samples such as solutions, thick, and thin films, it is possible to control the polarization degree spectrum associated to the fluorescence emitted by the polymer's isolated chains and aggregates. We show that the polarization degree could become a powerful tool to obtain information related to the samples morphology, which is connected to their microscopic structure. Moreover, the polarization degree spectra suggest that depolarization effects linked to energy and charge transfer mechanisms are likely taking place. Our findings indicate that P(NDI2OD-T2) polymers are excellent candidates for the advancement of organic technologies that rely on the emission and detection of polarized lights.
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http://dx.doi.org/10.1088/1361-648X/aac634DOI Listing
July 2018

Insemination with border disease virus-infected semen results in seroconversion in cows but not persistent infection in fetuses.

BMC Vet Res 2018 May 16;14(1):159. Epub 2018 May 16.

Institute for Virology and Immunology, and Department of Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, Bern, Switzerland.

Background: This study examined various health variables in cows after artificial insemination with Border disease virus (BDV)-infected semen and the occurrence of persistent infection in ensuing fetuses. Five cows were inseminated (day 0) with BDV-infected semen as well as with semen from a fertile Eringer bull. One cow, inseminated with virus-free semen only, served as a control. Clinical examination, assessment of eating and rumination activities, measurement of intraruminal temperature and leukocyte count were used to monitor the health of the cows. Blood samples were collected at regular intervals for the detection of viral RNA and antibodies against BDV, and the cows were slaughtered on day 56. The uteri, placentae and fetuses were examined macroscopically, histologically, immunohistochemically and by means of molecular methods for the presence of pestiviruses.

Results: The demeanour, eating and rumination activities and intraruminal temperature were not affected by insemination with BDV-infected semen, whereas the total leukocyte and lymphocyte counts dropped transiently and were significantly lower on day 6 than on day 0. Seroconversion occurred by day 28 in the five infected cows but not in the control cow. The uteri, placentae and fetuses had no macroscopic or histological lesions, and immunohistochemical examination and RT-PCR were negative for pestiviruses.

Conclusions: The findings showed that cows inseminated with BDV-infected semen seroconverted and fetuses thus produced were not persistently infected. Transmission of BDV to cattle through infected semen, therefore, seems to be of minor importance.
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http://dx.doi.org/10.1186/s12917-018-1472-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5954452PMC
May 2018

Border Disease Virus Infection of Bovine Placentas.

Vet Pathol 2018 05 5;55(3):425-433. Epub 2018 Feb 5.

1 Vetsuisse Faculty, Institute of Veterinary Pathology, University of Zurich, Zurich, Switzerland.

Subsequent to a previous study of border disease virus (BDV) horizontal transmission from a persistently BDV-infected calf to 6 seronegative pregnant heifers, the heifers were slaughtered 60 days after exposure to the infected calf, and their fetuses and placentas were examined. Immunohistochemical examination of fetal organs and placenta showed positive labeling of moderate intensity for pestivirus antigen in 3 of 6 heifers. BDV infection in these 3 animals was confirmed by the detection of BDV RNA in different organs using reverse transcription quantitative polymerase chain reaction. In the placenta, the positive cells were visualized mostly on the fetal side. In those 3 heifers that harbored an infected fetus, the placental tissue in the placentome region showed a moderate to severe mononuclear and fibrosing placentitis and, in severe cases, necrotic areas. The inflammatory population was composed predominantly of T and B cells, a substantial number of macrophages, and, to a lesser extent, plasma cells. This is a novel report of placentitis in persistently BDV-infected fetuses from pregnant heifers that became acutely infected by cohousing with a calf persistently infected with BDV, which extends previous reports on bovine viral diarrhea virus-infected and BDV-infected cattle and sheep, respectively.
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http://dx.doi.org/10.1177/0300985817754123DOI Listing
May 2018

Mycoplasma bovis co-infection with bovine viral diarrhea virus in bovine macrophages.

Vet Res 2018 01 9;49(1). Epub 2018 Jan 9.

Institute of Veterinary Bacteriology, Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, Laenggass-Str. 122, 3001, Bern, Switzerland.

Several studies suggest that synergisms between Mycoplasma bovis and other microorganisms might exacerbate disease outcome of bovine mycoplasmosis. Screening several bovine cell types to assess their potential use as in vitro infection models for M. bovis, it was observed that a widely used cell line of bovine macrophages (Bomac cells) is in fact persistently infected with bovine viral diarrhea virus (BVDV). The cell line was first cured of this virus allowing comparative studies between both cell lines. Subsequently, uptake and co-culture of two M. bovis strains of different clonal complexes with Bomac cells contaminated with BVDV and in BVDV-free Bomac cells were assessed. Additionally, cell viability, cytotoxicity and induction of apoptosis after infection with M. bovis were evaluated. No differences in the levels of uptake and growth in co-culture were observed between the two Bomac cell types and both M. bovis strains. Cytotoxicity was increased after infection of BVDV-free cells with one of the two strains, while apoptotic cell death was slightly induced by this strain in both cell lines. Overall, the presence or absence of BVDV in Bomac cells did not grossly change the parameters tested upon infection with M. bovis. Nevertheless, this cell model is very useful when studying viral co-infections with bacteria and could also be used for multiple co-infections. Considering the broad contamination of cell cultures with BVDV, careful screening for this virus should routinely be performed as its presence might be relevant depending on the molecular mechanisms being investigated.
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http://dx.doi.org/10.1186/s13567-017-0499-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5761114PMC
January 2018

Complete Genome Sequences of Three Border Disease Virus Strains of the Same Subgenotype, BDSwiss, Isolated from Sheep, Cattle, and Pigs in Switzerland.

Genome Announc 2017 Nov 9;5(45). Epub 2017 Nov 9.

Institute of Virology and Immunology, Bern and Mittelhäusern, Switzerland, and Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, Bern, Switzerland

We report here the complete genome sequences of three border disease virus (BDV) strains of the same subgenotype isolated in Switzerland from a sheep, a cow, and a pig, respectively. This is the first report of full-length sequences of a tentatively new subgenotype isolated from three different species of cloven-hoofed farm animals.
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http://dx.doi.org/10.1128/genomeA.01238-17DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5679808PMC
November 2017

Tropism, intracerebral distribution, and transduction efficiency of HIV- and SIV-based lentiviral vectors after injection into the mouse brain: a qualitative and quantitative in vivo study.

Histochem Cell Biol 2017 Sep 10;148(3):313-329. Epub 2017 Apr 10.

Department of Pathobiology, Institute of Anatomy, Histology and Embryology, University of Veterinary Medicine Vienna, Veterinärplatz 1, 1210, Vienna, Austria.

Lentiviruses are suitable to transfer potential therapeutic genes into non-replicating cells such as neurons, but systematic in vivo studies on transduction of neural cells within the complete brain are missing. We analysed the distribution of transduced cells with respect to brain structure, virus tropism, numbers of transduced neurons per brain, and influence of the Vpx or Vpr accessory proteins after injection of vectors based on SIVsmmPBj, HIV-2, and HIV-1 lentiviruses into the right striatum of the mouse brain. Transduced cells were found ipsilaterally around the injection canal, in corpus striatum and along corpus callosum, irrespective of the vector type. All vectors except HIV-2SEW transduced also single cells in the olfactory bulb, hippocampus, and cerebellum. Vector HIV-2SEW was the most neuron specific. However, vectors PBjSEW and HIV-1SEW transduced more neurons per brain (means 41,299 and 32,309) than HIV-2SEW (16,102). In the presence of Vpx/Vpr proteins, HIV-2SEW(Vpx) and HIV-1SEW(Vpr) showed higher overall transduction efficiencies (30,696 and 27,947 neurons per brain) than PBjSEW(Vpx) (6636). The distances of transduced cells from the injection canal did not differ among the viruses but correlated positively with the numbers of transduced neurons. The presence of Vpx/Vpr did not increase the numbers of transduced neurons. Parental virus type and the vector equipment seem to influence cellular tropism and transduction efficiency. Thus, precision of injection and choice of virus pseudotype are not sufficient when targeted lentiviral vector transduction of a defined brain cell population is required.
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http://dx.doi.org/10.1007/s00418-017-1569-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5539277PMC
September 2017

What can pestiviral endonucleases teach us about innate immunotolerance?

Cytokine Growth Factor Rev 2016 06 17;29:53-62. Epub 2016 Mar 17.

Institute of Virology and Immunology, Federal Food Safety and Veterinary Office (FSVO) and Vetsuisse Faculty University of Bern, Laenggass-Str. 122, CH-3001 Bern, Switzerland. Electronic address:

Pestiviruses including bovine viral diarrhea virus (BVDV), border disease virus (BDV) and classical swine fever virus (CSFV), occur worldwide and are important pathogens of livestock. A large part of their success can be attributed to the induction of central immunotolerance including B- and T-cells upon fetal infection leading to the generation of persistently infected (PI) animals. In the past few years, it became evident that evasion of innate immunity is a central element to induce and maintain persistent infection. Hence, the viral non-structural protease N(pro) heads the transcription factor IRF-3 for proteasomal degradation, whereas an extracellularly secreted, soluble form of the envelope glycoprotein E(rns) degrades immunostimulatory viral single- and double-stranded RNA, which makes this RNase unique among viral endoribonucleases. We propose that these pestiviral interferon (IFN) antagonists maintain a state of innate immunotolerance mainly pertaining its viral nucleic acids, in contrast to the well-established immunotolerance of the adaptive immune system, which is mainly targeted at proteins. In particular, the unique extension of 'self' to include the viral genome by degrading immunostimulatory viral RNA by E(rns) is reminiscent of various host nucleases that are important to prevent inappropriate IFN activation by the host's own nucleic acids in autoimmune diseases such as Aicardi-Goutières syndrome or systemic lupus erythematosus. This mechanism of "innate tolerance" might thus provide a new facet to the role of extracellular RNases in the sustained prevention of the body's own immunostimulatory RNA to act as a danger-associated molecular pattern that is relevant across various species.
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http://dx.doi.org/10.1016/j.cytogfr.2016.03.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7173139PMC
June 2016

Interferon but not MxB inhibits foamy retroviruses.

Virology 2016 Jan 21;488:51-60. Epub 2015 Nov 21.

Clinic for Gastroenterology, Hepatology, and Infectiology, Medical Faculty, Heinrich-Heine-University, Moorenstr. 5, 40225 Düsseldorf, Germany. Electronic address:

Foamy viruses (FV) are retroviruses that are widely distributed in primate and non-primate animal species. We tested here FV with capsids of simian and non-simian origin for sensitivity to interferon-β (IFN-β). Our data show significant inhibition of FV by IFN-β early in infection of human HOS and THP-1 but not of HEK293T cells. The post-entry restriction of FV was not mediated by the interferon-induced MxB protein that was recently identified as a capsid-interacting restriction factor targeting Human immunodeficiency virus (HIV) before integration. Neither the ectopic expression of MxA or MxB in HEK293T cells nor the lack of MxB expression in CRISPR/CAS MxB THP-1 knockout cells impacted the infection of the tested FV. IFN-β treated THP-1 and THP-1 KO MxB cells showed the same extend of restriction to FV. Together, the data demonstrate that IFN-β inhibits FV early in infection and that MxB is not a restriction factor of FV.
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http://dx.doi.org/10.1016/j.virol.2015.10.034DOI Listing
January 2016

A nationwide database linking information on the hosts with sequence data of their virus strains: A useful tool for the eradication of bovine viral diarrhea (BVD) in Switzerland.

Virus Res 2016 06 25;218:49-56. Epub 2015 Sep 25.

Institute of Veterinary Virology, Vetsuisse Faculty University of Bern, Laenggass-Str. 122, PO Box 8466, CH-3001 Bern, Switzerland. Electronic address:

Pestiviruses infect a wide variety of animals of the order Artiodactyla, with bovine viral diarrhea virus (BVDV) being an economically important pathogen of livestock globally. BVDV is maintained in the cattle population by infecting fetuses early in gestation and, thus, by generating persistently infected (PI) animals that efficiently transmit the virus throughout their lifetime. In 2008, Switzerland started a national control campaign with the aim to eradicate BVDV from all bovines in the country by searching for and eliminating every PI cattle. Different from previous eradication programs, all animals of the entire population were tested for virus within one year, followed by testing each newborn calf in the subsequent four years. Overall, 3,855,814 animals were tested from 2008 through 2011, 20,553 of which returned an initial BVDV-positive result. We were able to obtain samples from at least 36% of all initially positive tested animals. We sequenced the 5' untranslated region (UTR) of more than 7400 pestiviral strains and compiled the sequence data in a database together with an array of information on the PI animals, among others, the location of the farm in which they were born, their dams, and the locations where the animals had lived. To our knowledge, this is the largest database combining viral sequences with animal data of an endemic viral disease. Using unique identification tags, the different datasets within the database were connected to run diverse molecular epidemiological analyses. The large sets of animal and sequence data made it possible to run analyses in both directions, i.e., starting from a likely epidemiological link, or starting from related sequences. We present the results of three epidemiological investigations in detail and a compilation of 122 individual investigations that show the usefulness of such a database in a country-wide BVD eradication program.
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http://dx.doi.org/10.1016/j.virusres.2015.09.012DOI Listing
June 2016

[Therapeutic approaches using genetically modified cells].

Bundesgesundheitsblatt Gesundheitsforschung Gesundheitsschutz 2015 Nov;58(11-12):1274-80

Paul-Ehrlich-Institut, Fachgebiet 6/2, Paul-Ehrlich-Straße 51-59, 63225, Langen, Deutschland.

Medicinal products containing genetically modified cells are, in most cases, classified as gene therapy and cell therapy medicinal products. Although no medicinal product containing genetically modified cells has been licensed in Europe yet, a variety of therapeutic strategies using genetically modified cells are in different stages of clinical development for the treatment of acquired and inherited diseases. In this chapter, several examples of promising approaches are presented, with an emphasis on gene therapy for inherited immunodeficiencies and on tumour immunotherapy with genetically modified T-cells expressing a chimeric antigen receptor or a recombinant T-cell receptor.
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http://dx.doi.org/10.1007/s00103-015-2245-zDOI Listing
November 2015

Complete Genome Sequence of a Bovine Viral Diarrhea Virus Subgenotype 1e Strain Isolated in Switzerland.

Genome Announc 2015 Jun 11;3(3). Epub 2015 Jun 11.

Institute of Virology, Vetsuisse Faculty University of Zurich, Zurich, Switzerland.

We sequenced the complete genome of the bovine viral diarrhea virus (BVDV) strain Carlito. It belongs to the subgenotype 1e that is described in Europe only and represents the second most prevalent subgenotype in Switzerland. This is the first report of a full-length sequence of BVDV-1e.
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http://dx.doi.org/10.1128/genomeA.00636-15DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4463535PMC
June 2015

Transmission of border disease virus from a persistently infected calf to seronegative heifers in early pregnancy.

BMC Vet Res 2015 Feb 22;11:43. Epub 2015 Feb 22.

Institute of Veterinary Virology, Vetsuisse-Faculty, University of Bern, Länggass-Strasse 122, 3001, Bern, Switzerland.

Background: This study describes the transmission of border disease virus (BDV) from a persistently infected calf to seronegative heifers in early pregnancy, resulting in persistently infected fetuses. On day 50 of pregnancy (= day 0 of the infection phase), six heifers were co-housed in a free stall with a bull calf persistently infected with BDV (pi BVD) for 60 days. The heifers underwent daily clinical examination, and blood samples were collected regularly for detection of pestiviral RNA and anti-pestivirus antibodies. After day 60 (= day 110 of pregnancy), the heifers were slaughtered, and the fetuses and placentae underwent post-mortem and immunohistochemical examination and RT-PCR for viral RNA detection.

Results: Three heifers had mild viraemia from day 8 to day 14, and by day 40 all heifers had pestivirus antibodies identified as anti-BDV antibodies in the serum neutralisation test. The placenta of the three viraemic heifers had histological evidence of inflammation, and fetal organs from these heifers were positive for pestivirus antigen by immunohistochemical examination and for BD viral RNA by RT-PCR and sequencing. Thus, co-housing of heifers in early pregnancy with a pi-BDV calf led to seroconversion in all heifers and persistent fetal infection in three.

Conclusions: Considering that pi-BDV cattle can infect other cattle and lead to persistent infection of the fetus in pregnant cows, BDV should not be ignored in the context of the mandatory BVDV eradication and monitoring program. This strongly suggests that BDV should be taken into account in BVD eradication and control programs.
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http://dx.doi.org/10.1186/s12917-014-0275-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4336514PMC
February 2015

Pestiviral E(rns) blocks TLR-3-dependent IFN synthesis by LL37 complexed RNA.

Vet Microbiol 2014 Dec 13;174(3-4):399-408. Epub 2014 Oct 13.

Institute of Veterinary Virology (current name: Institute of Virology and Immunology), Vetsuisse Faculty University of Bern, Laenggass-Str. 122, CH-3001 Bern, Switzerland. Electronic address:

The ribonuclease activity of the soluble glycoprotein E(rns) of pestiviruses represents a unique mechanism to circumvent the host's innate immune system by blocking interferon type-I synthesis in response to extracellularly added single- (ss) and double-stranded (ds) RNA. However, the reason why pestiviruses encode a ribonuclease in addition to the abundant serum RNases remained elusive. Here, we show that the 5' UTR and NS5B regions of various strains of the RNA genome of the pestivirus bovine viral diarrhea virus (BVDV) are resistant to serum RNases and are potent TLR-3 agonists. Inhibitory activity of E(rns) was restricted to cleavable RNA products, and did not extend to the synthetic TLR-7/8 agonist R-848. RNA complexed with the antimicrobial peptide LL37 was protected from degradation by E(rns)in vitro but was fully inhibited by E(rns) in its ability to induce IFN in cell cultures, suggesting that the viral protein is mainly active in cleaving RNA in an intracellular compartment. We propose that secreted E(rns) represents a potent IFN antagonist, which degrades viral RNA that is resistant to the ubiquitous host RNases in the extracellular space. Thus, the viral RNase prevents its own pathogen-associated molecular pattern (PAMP) to inadvertently activate the IFN response that might break innate immunotolerance required for persistent pestivirus infections.
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http://dx.doi.org/10.1016/j.vetmic.2014.09.028DOI Listing
December 2014

Pestiviruses.

Annu Rev Anim Biosci 2014 Feb 6;2:141-63. Epub 2013 Nov 6.

Institute of Veterinary Virology, University of Bern, CH-3001 Bern, Switzerland; email: ,

Pestiviruses cause economically important diseases among domestic ruminants and pigs, but they may also infect a wide spectrum of wild species of even-toed ungulates (Artiodactyla). Bovine viral diarrhea virus (BVDV) and Border disease virus of sheep infect their hosts either transiently or persistently. Cellular and humoral immunotolerance to the infecting strain is a unique feature of persistent infection (PI) by ruminant pestiviruses. Persistence, caused by transplacental infection early in fetal development, depends on virally encoded interferon antagonists that inactivate the host's innate immune response to the virus without globally interfering with its function against other viruses. At epidemiological equilibrium, approximately 1-2% of animals are PI. Successful BVDV control programs show that removal of PI animals results in viral extinction in the host population. The nucleotide sequences of ruminant pestiviruses change little during persistent infection. Nevertheless, they display large heterogeneity, pointing to a long history of virus-host coevolution in which avirulent strains are more successful.
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http://dx.doi.org/10.1146/annurev-animal-022513-114209DOI Listing
February 2014

Complete Genome Sequence of Bovine Pestivirus Strain PG-2, a Second Member of the Tentative Pestivirus Species Giraffe.

Genome Announc 2014 May 15;2(3). Epub 2014 May 15.

Institute of Virology, University of Veterinary Medicine, Hannover, Germany.

We report the complete genome sequence of bovine pestivirus strain PG-2. The sequence data from this virus showed that PG-2 is closely related to the giraffe pestivirus strain H138. PG-2 and H138 belong to one pestivirus species that should be considered an approved member of the genus Pestivirus.
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http://dx.doi.org/10.1128/genomeA.00376-14DOI Listing
May 2014

Prolonged activity of the pestiviral RNase Erns as an interferon antagonist after uptake by clathrin-mediated endocytosis.

J Virol 2014 Jul 16;88(13):7235-43. Epub 2014 Apr 16.

Institute of Veterinary Virology, University of Bern, Bern, Switzerland

Unlabelled: The RNase activity of the envelope glycoprotein E(rns) of the pestivirus bovine viral diarrhea virus (BVDV) is required to block type I interferon (IFN) synthesis induced by single-stranded RNA (ssRNA) and double-stranded RNA (dsRNA) in bovine cells. Due to the presence of an unusual membrane anchor at its C terminus, a significant portion of E(rns) is also secreted. In addition, a binding site for cell surface glycosaminoglycans is located within the C-terminal region of E(rns). Here, we show that the activity of soluble E(rns) as an IFN antagonist is not restricted to bovine cells. Extracellularly applied E(rns) protein bound to cell surface glycosaminoglycans and was internalized into the cells within 1 h of incubation by an energy-dependent mechanism that could be blocked by inhibitors of clathrin-dependent endocytosis. E(rns) mutants that lacked the C-terminal membrane anchor retained RNase activity but lost most of their intracellular activity as an IFN antagonist. Surprisingly, once taken up into the cells, E(rns) remained active and blocked dsRNA-induced IFN synthesis for several days. Thus, we propose that E(rns) acts as an enzymatically active decoy receptor that degrades extracellularly added viral RNA mainly in endolysosomal compartments that might otherwise activate intracellular pattern recognition receptors (PRRs) in order to maintain a state of innate immunotolerance.

Importance: The pestiviral RNase E(rns) was previously shown to inhibit viral ssRNA- and dsRNA-induced interferon (IFN) synthesis. However, the localization of E(rns) at or inside the cells, its species specificity, and its mechanism of interaction with cell membranes in order to block the host's innate immune response are still largely unknown. Here, we provide strong evidence that the pestiviral RNase E(rns) is taken up within minutes by clathrin-mediated endocytosis and that this uptake is mostly dependent on the glycosaminoglycan binding site located within the C-terminal end of the protein. Remarkably, the inhibitory activity of E(rns) remains for several days, indicating the very potent and prolonged effect of a viral IFN antagonist. This novel mechanism of an enzymatically active decoy receptor that degrades a major viral pathogen-associated molecular pattern (PAMP) might be required to efficiently maintain innate and, thus, also adaptive immunotolerance, and it might well be relevant beyond the bovine species.
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http://dx.doi.org/10.1128/JVI.00672-14DOI Listing
July 2014

[Bovine viral diarrhea (BVD): from biology to control].

Berl Munch Tierarztl Wochenschr 2013 Nov-Dec;126(11-12):452-61

Institut für Veterinar Virologie der Universität Bern, Schweiz.

Bovine viral diarrhea virus (BVDV) is endemic worldwide. Together with classical swine fever and border disease viruses, it belongs to the genus Pestivirus of the family Flaviviridae. Most infections with BVDV take a transient, acute, course. Only rarely BVDV persists in its hosts. Due to the early time point of infection in utero, persistently infected (PI) animals are immunotolerant to the infecting non-cytopathic BVDV. In such animals the virus may mutate to a cytopathic biotype, causing lethal mucosal disease. In BVD-endemic regions, approximately 1% of the animals are PI. Removal of all PI animals leads to extinction of BVD. This approach to BVD eradication has been vindicated in Scandinavia. Following the same principles, regional and country-wide eradication programs are run in different parts of the world. These programs differ in the way PI animals are detected and in the role of vaccines. The Scandinavian two-step method of detecting PI animals is based on (i) the high level of seroprevalence in herds where PI animals are present and (ii) on testing all animals for virus in such herds. However, the high average herd seroprevalence in Switzerland made it impossible to define a reasonable threshold for virus testing. Therefore, all animals were directly tested for virus in the year 2008 and all newborn calves until the end of 2012, when the PI prevalence had dropped to 0.02%. Vaccination remains prohibited. Since 2013, surveillance for BVD is accomplished by serology. As a unique consequence of eradication, over 7500 viral strains are available to us for genetic studies.
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April 2015

Bovine viral diarrhoea: a playground for virologists and a target for eradication.

Vet J 2014 Feb 27;199(2):195-6. Epub 2013 Nov 27.

Institute of Veterinary Virology, University of Bern, PO Box 8466, CH-3001 Bern, Switzerland. Electronic address:

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http://dx.doi.org/10.1016/j.tvjl.2013.11.015DOI Listing
February 2014
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