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Wang L, Madera R, Li Y, Gladue DP, Borca MV, McIntosh MT, Shi J. Development of Porcine Monoclonal Antibodies with In Vitro Neutralizing Activity against Classical Swine Fever Virus from C-Strain E2-Specific Single B Cells. Viruses 2023; 15:v15040863. [PMID: 37112845 PMCID: PMC10145741 DOI: 10.3390/v15040863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 03/23/2023] [Accepted: 03/27/2023] [Indexed: 03/30/2023] Open
Abstract
Neutralizing antibodies (nAbs) can be used before or after infection to prevent or treat viral diseases. However, there are few efficacious nAbs against classical swine fever virus (CSFV) that have been produced, especially the porcine-originated nAbs. In this study, we generated three porcine monoclonal antibodies (mAbs) with in vitro neutralizing activity against CSFV, aiming to facilitate the development of passive antibody vaccines or antiviral drugs against CSFV that offer the advantages of stability and low immunogenicity. Pigs were immunized with the C-strain E2 (CE2) subunit vaccine, KNB-E2. At 42 days post vaccination (DPV), CE2-specific single B cells were isolated via fluorescent-activated cell sorting (FACS) baited by Alexa Fluor™ 647-labeled CE2 (positive), goat anti-porcine IgG (H + L)-FITC antibody (positive), PE mouse anti-pig CD3ε (negative) and PE mouse anti-pig CD8a (negative). The full coding region of IgG heavy (H) chains and light (L) chains was amplified by reverse transcription-polymerase chain reaction (RT-PCR). Overall, we obtained 3 IgG H chains, 9 kappa L chains and 36 lambda L chains, which include three paired chains (two H + κ and one H + λ). CE2-specific mAbs were successfully expressed in 293T cells with the three paired chains. The mAbs exhibit potent neutralizing activity against CSFVs. They can protect ST cells from infections in vitro with potent IC50 values from 14.43 µg/mL to 25.98 µg/mL for the CSFV C-strain, and 27.66 µg/mL to 42.61 µg/mL for the CSFV Alfort strain. This study is the first report to describe the amplification of whole-porcine IgG genes from single B cells of KNB-E2-vaccinated pig. The method is versatile, sensitive, and reliable. The generated natural porcine nAbs can be used to develop long-acting and low-immunogenicity passive antibody vaccine or anti-CSFV agents for CSF control and prevention.
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Affiliation(s)
- Lihua Wang
- Department of Anatomy and Physiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA; (R.M.); (Y.L.)
- Correspondence: (L.W.); (J.S.); Tel.: +1-(785)-706-3796 (L.W.); +1-(785)-532-4506 (J.S.)
| | - Rachel Madera
- Department of Anatomy and Physiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA; (R.M.); (Y.L.)
| | - Yuzhen Li
- Department of Anatomy and Physiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA; (R.M.); (Y.L.)
| | - Douglas P. Gladue
- Department of Agriculture, Agricultural Research Service, Plum Island Animal Disease Center, Greenport, NY 11944, USA; (D.P.G.); (M.V.B.)
| | - Manuel V. Borca
- Department of Agriculture, Agricultural Research Service, Plum Island Animal Disease Center, Greenport, NY 11944, USA; (D.P.G.); (M.V.B.)
| | - Michael T. McIntosh
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL 32611, USA;
- Child Health Research Institute, Department of Pediatrics, University of Florida, Gainesville, FL 32611, USA
| | - Jishu Shi
- Department of Anatomy and Physiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA; (R.M.); (Y.L.)
- Correspondence: (L.W.); (J.S.); Tel.: +1-(785)-706-3796 (L.W.); +1-(785)-532-4506 (J.S.)
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Postel A, Becher P. Genetically distinct pestiviruses pave the way to improved classical swine fever marker vaccine candidates based on the chimeric pestivirus concept. Emerg Microbes Infect 2021; 9:2180-2189. [PMID: 32962557 PMCID: PMC7580611 DOI: 10.1080/22221751.2020.1826893] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Classical swine fever (CSF) is one of the most important viral diseases of pigs. In many countries, the use of vaccines is restricted due to limitations of subunit vaccines with regard to efficacy and onset of protection as well as failure of live vaccines to differentiate infected from vaccinated animals (DIVA principle). Chimeric pestiviruses based on CSF virus (CSFV) and the related bovine viral diarrhea virus (BVDV) have been licensed as live marker vaccines in Europe and Asia, but cross-reactive antibodies can cause problems in DIVA application due to close antigenic relationship. To develop marker vaccine candidates with improved DIVA properties, three chimeric viruses were generated by replacing Erns of CSFV Alfort-Tübingen with homologue proteins of only distantly related pestiviruses. The chimeric viruses “Ra”, “Pro”, and “RaPro” contained Erns sequences of Norway rat and Pronghorn pestiviruses or a combination of both, respectively. In porcine cells, the “Pro” chimera replicated to high titers, while replication of the “Ra” chimera was limited. The “RaPro” chimera showed an intermediate phenotype. All vaccine candidates were attenuated in a vaccination/ challenge trial in pigs, but to different extents. Inoculation induced moderate to high levels of neutralizing antibodies that protected against infection with a genetically heterologous, highly virulent CSFV. Importantly, serum samples of vaccinated animals did not show any cross-reactivity in a CSFV Erns antibody ELISA. In conclusion, the Erns antigen from distantly related pestiviruses can provide a robust serological negative marker for a new generation of improved CSFV marker vaccines based on the chimeric pestivirus concept.
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Affiliation(s)
- Alexander Postel
- Institute of Virology, Department of Infectious Diseases, University of Veterinary Medicine, Hannover, Germany
| | - Paul Becher
- Institute of Virology, Department of Infectious Diseases, University of Veterinary Medicine, Hannover, Germany
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Research Progress and Challenges in Vaccine Development against Classical Swine Fever Virus. Viruses 2021; 13:v13030445. [PMID: 33801868 PMCID: PMC7998128 DOI: 10.3390/v13030445] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 03/01/2021] [Accepted: 03/04/2021] [Indexed: 01/06/2023] Open
Abstract
Classical swine fever (CSF), caused by CSF virus (CSFV), is one of the most devastating viral epizootic diseases of swine in many countries. To control the disease, highly efficacious and safe live attenuated vaccines have been used for decades. However, the main drawback of these conventional vaccines is the lack of differentiability of infected from vaccinated animals (DIVA concept). Advances in biotechnology and our detailed knowledge of multiple basic science disciplines have facilitated the development of effective and safer DIVA vaccines to control CSF. To date, two types of DIVA vaccines have been developed commercially, including the subunit vaccines based on CSFV envelope glycoprotein E2 and chimeric pestivirus vaccines based on infectious cDNA clones of CSFV or bovine viral diarrhea virus (BVDV). Although inoculation of these vaccines successfully induces solid immunity against CSFV, none of them could ideally meet all demands regarding to safety, efficacy, DIVA potential, and marketability. Due to the limitations of the available choices, researchers are still striving towards the development of more advanced DIVA vaccines against CSF. This review summarizes the present status of candidate CSFV vaccines that have been developed. The strategies and approaches revealed here may also be helpful for the development of new-generation vaccines against other diseases.
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Coronado L, Perera CL, Rios L, Frías MT, Pérez LJ. A Critical Review about Different Vaccines against Classical Swine Fever Virus and Their Repercussions in Endemic Regions. Vaccines (Basel) 2021; 9:154. [PMID: 33671909 PMCID: PMC7918945 DOI: 10.3390/vaccines9020154] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 01/31/2021] [Accepted: 02/09/2021] [Indexed: 12/24/2022] Open
Abstract
Classical swine fever (CSF) is, without any doubt, one of the most devasting viral infectious diseases affecting the members of Suidae family, which causes a severe impact on the global economy. The reemergence of CSF virus (CSFV) in several countries in America, Asia, and sporadic outbreaks in Europe, sheds light about the serious concern that a potential global reemergence of this disease represents. The negative aspects related with the application of mass stamping out policies, including elevated costs and ethical issues, point out vaccination as the main control measure against future outbreaks. Hence, it is imperative for the scientific community to continue with the active investigations for more effective vaccines against CSFV. The current review pursues to gather all the available information about the vaccines in use or under developing stages against CSFV. From the perspective concerning the evolutionary viral process, this review also discusses the current problematic in CSF-endemic countries.
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Affiliation(s)
- Liani Coronado
- National Centre for Animal and Plant Health (CENSA), OIE Collaborating Centre for Disaster Risk Reduction in Animal Health, San José de las Lajas 32700, Cuba; (L.C.); (C.L.P.); (M.T.F.)
| | - Carmen L. Perera
- National Centre for Animal and Plant Health (CENSA), OIE Collaborating Centre for Disaster Risk Reduction in Animal Health, San José de las Lajas 32700, Cuba; (L.C.); (C.L.P.); (M.T.F.)
| | - Liliam Rios
- Reiman Cancer Research Laboratory, Faculty of Medicine, University of New Brunswick, Saint John, NB E2L 4L5, Canada;
| | - María T. Frías
- National Centre for Animal and Plant Health (CENSA), OIE Collaborating Centre for Disaster Risk Reduction in Animal Health, San José de las Lajas 32700, Cuba; (L.C.); (C.L.P.); (M.T.F.)
| | - Lester J. Pérez
- Veterinary Diagnostic Laboratory, College of Veterinary Medicine, University of Illinois at Urbana–Champaign, Champaign, IL 61802, USA
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Han Y, Xie L, Yuan M, Ma Y, Sun H, Sun Y, Li Y, Qiu HJ. Development of a marker vaccine candidate against classical swine fever based on the live attenuated vaccine C-strain. Vet Microbiol 2020; 247:108741. [PMID: 32768202 DOI: 10.1016/j.vetmic.2020.108741] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 05/26/2020] [Accepted: 05/26/2020] [Indexed: 12/29/2022]
Abstract
Classical swine fever (CSF) is a highly contagious and economically damaging disease. Classical swine fever virus (CSFV) lapinized vaccine C-strain against CSF worldwide lacks the capacity for the serological differentiation between infected and vaccinated animals (DIVA). To develop a marker C-strain complying with the DIVA principle, we generated and evaluated mutants rHCLV-E2F117A, rHCLV-E2G119A, and rHCLV-E2P122A, which harbor the single amino acid mutation at 117F, 119G or 122P of the monoclonal antibody HQ06-recognized epitope on the E2 glycoprotein in rabbits and pigs. Viral intravenous administration demonstrated that all the mutants retain the phenotype of C-strain in rabbits, including fever response induction and replication in the spleen. Notably, the HQ06-recognized epitope did not react with the antibodies induced by rHCLV-E2P122A in rabbits, in contrast with C-strain and other two mutants. Intramuscular administration of rHCLV-E2P122A in pigs induced anti-CSFV neutralizing antibodies but not antibodies against the HQ06-recognized epitope at 28 days post-inoculation. Collectively, our data demonstrate that rHCLV-E2P122A is a promising marker vaccine candidate against CSF.
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Affiliation(s)
- Yuying Han
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Libao Xie
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Mengqi Yuan
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Yuteng Ma
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Huimin Sun
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Yuan Sun
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Yongfeng Li
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China.
| | - Hua-Ji Qiu
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China.
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6
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Tran HTT, Truong DA, Ly VD, Vu HT, Hoang TV, Nguyen CT, Chu NT, Nguyen VT, Nguyen DT, Miyazawa K, Kokuho T, Dang HV. The potential efficacy of the E2-subunit vaccine to protect pigs against different genotypes of classical swine fever virus circulating in Vietnam. Clin Exp Vaccine Res 2020; 9:26-39. [PMID: 32095438 PMCID: PMC7024730 DOI: 10.7774/cevr.2020.9.1.26] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 01/19/2020] [Accepted: 01/21/2020] [Indexed: 11/15/2022] Open
Abstract
Purpose To date, many kinds of classical swine fever (CSF) vaccines have been developed to protect against this disease. However, the efficacy of these vaccines to protect the pig against field CSF strains needs to be considered, based on circulating strains of classical swine fever virus (CSFV). Materials and Methods Recombinant E2-CSFV protein produced by baculovirus/insect cell system was analyzed by western blots and immunoperoxidase monolayer assay. The effect of CSFV-E2 subunit vaccines was evaluated in experimental pigs with three genotypes of CSFV challenge. Anti-E2 specific and neutralizing antibodies in experimental pigs were analyzed by blocking enzyme-linked immunosorbent assay and neutralization peroxidize-linked assay. Results The data showed that CSFV VN91-E2 subunit vaccine provided clinical protection in pigs against three different genotypes of CSFV without noticeable clinical signs, symptoms, and mortality. In addition, no CSFV was isolated from the spleen of the vaccinated pigs. However, the unvaccinated pigs exhibited high clinical scores and the successful virus isolation from spleen. These results showed that the E2-specific and neutralizing antibodies induced by VN91-E2 antigen appeared at day 24 after first boost and a significant increase was observed at day 28 (p<0.01). This response reached a peak at day 35 and continued until day 63 when compared to controls. Importantly, VN91-E2 induced E2-specific and neutralizing antibodies protected experimental pigs against high virulence of CSFVs circulating in Vietnam, including genotype 1.1, 2.1, and 2.2. Conclusion These findings also suggested that CSFV VN91-E2 subunit vaccine could be a promising vaccine candidate for the control and prevention of CSFV in Vietnam.
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Affiliation(s)
- Ha Thi Thanh Tran
- Department of Biochemistry and Immunology, National Institute of Veterinary Research (NIVR), Hanoi, Vietnam
| | - Duc Anh Truong
- Department of Biochemistry and Immunology, National Institute of Veterinary Research (NIVR), Hanoi, Vietnam
| | - Viet Duc Ly
- Department of Biochemistry and Immunology, National Institute of Veterinary Research (NIVR), Hanoi, Vietnam
| | - Hao Thi Vu
- Department of Biochemistry and Immunology, National Institute of Veterinary Research (NIVR), Hanoi, Vietnam
| | - Tuan Van Hoang
- Department of Biochemistry and Immunology, National Institute of Veterinary Research (NIVR), Hanoi, Vietnam
| | - Chinh Thi Nguyen
- Department of Biochemistry and Immunology, National Institute of Veterinary Research (NIVR), Hanoi, Vietnam
| | - Nhu Thi Chu
- Department of Biochemistry and Immunology, National Institute of Veterinary Research (NIVR), Hanoi, Vietnam
| | - Vinh The Nguyen
- Department of Biochemistry and Immunology, National Institute of Veterinary Research (NIVR), Hanoi, Vietnam
| | - Duyen Thuy Nguyen
- Department of Biochemistry and Immunology, National Institute of Veterinary Research (NIVR), Hanoi, Vietnam
| | - Kohtaro Miyazawa
- National Institute of Animal Health, The National Agriculture and Food Research Organization, Tsukuba, Japan
| | - Takehiro Kokuho
- National Institute of Animal Health, The National Agriculture and Food Research Organization, Tsukuba, Japan
| | - Hoang Vu Dang
- Department of Biochemistry and Immunology, National Institute of Veterinary Research (NIVR), Hanoi, Vietnam
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Virus Adaptation and Selection Following Challenge of Animals Vaccinated against Classical Swine Fever Virus. Viruses 2019; 11:v11100932. [PMID: 31658773 PMCID: PMC6833067 DOI: 10.3390/v11100932] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 09/30/2019] [Accepted: 10/09/2019] [Indexed: 01/15/2023] Open
Abstract
Vaccines against classical swine fever have proven very effective in protecting pigs from this deadly disease. However, little is known about how vaccination impacts the selective pressures acting on the classical swine fever virus (CSFV). Here we use high-throughput sequencing of viral genomes to investigate evolutionary changes in virus populations following the challenge of naïve and vaccinated pigs with the highly virulent CSFV strain “Koslov”. The challenge inoculum contained an ensemble of closely related viral sequences, with three major haplotypes being present, termed A, B, and C. After the challenge, the viral haplotype A was preferentially located within the tonsils of naïve animals but was highly prevalent in the sera of all vaccinated animals. We find that the viral population structure in naïve pigs after infection is very similar to that in the original inoculum. In contrast, the viral population in vaccinated pigs, which only underwent transient low-level viremia, displayed several distinct changes including the emergence of 16 unique non-synonymous single nucleotide polymorphisms (SNPs) that were not detectable in the challenge inoculum. Further analysis showed a significant loss of heterogeneity and an increasing positive selection acting on the virus populations in the vaccinated pigs. We conclude that vaccination imposes a strong selective pressure on viruses that subsequently replicate within the vaccinated animal.
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Lim SI, Choe S, Kim KS, Jeoung HY, Cha RM, Park GS, Shin J, Park GN, Cho IS, Song JY, Hyun BH, Park BK, An DJ. Assessment of the efficacy of an attenuated live marker classical swine fever vaccine (Flc-LOM-BE rns) in pregnant sows. Vaccine 2019; 37:3598-3604. [PMID: 31151802 DOI: 10.1016/j.vaccine.2019.04.076] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 04/20/2019] [Accepted: 04/24/2019] [Indexed: 11/29/2022]
Abstract
Here, we constructed an attenuated live marker classical swine fever (CSF) vaccine (Flc-LOM-BErns) to eradicate CSF. This was done by taking infectious clone Flc-LOM, which is based on an attenuated live CSF vaccine virus (LOM strain), and removing the full-length classical swine fever virus (CSFV) Erns sequences and the 3' end (52 base pairs) of the CSFV capsid. These regions were substituted with the full-length bovine viral diarrhoea virus (BVDV) Erns gene sequence and the 3' end (52 base pairs) of the BVDV capsid gene. Sows were vaccinated with the Flc-LOM-BErns vaccine 3 weeks before insemination and then challenged with virulent CSFV at the early, mid- or late stages of pregnancy. We then examined transplacental transmission to the foetuses. Piglets born to sows vaccinated with Flc-LOM-BErns did not show vertical infection, regardless of challenge time. In addition, CSFV challenge did not affect the delivery date, weight or length of the foetus. Pregnant sows inoculated with the Flc-LOM-BErns vaccine were anti-CSF Erns antibody-negative and anti-BVDV Erns antibody-positive. Challenge of pregnant sows with virulent CSFV resulted in anti-CSF Erns antibody positivity. These results strongly indicate that differential diagnosis can be conducted between the Flc-LOM-BErns vaccinated animal and virulent CSFV affected animal by detecting antibody against BVDV Erns or CSF Erns gene. Therefore, the Flc-LOM-BErns vaccine may fulfil the function of differential diagnosis which required for DIVA vaccine.
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Affiliation(s)
- Seong-In Lim
- Virus Disease Division, Animal and Plant Quarantine Agency, Gimchen, Gyeongbuk-do, 39660, South Korea
| | - SeEun Choe
- Virus Disease Division, Animal and Plant Quarantine Agency, Gimchen, Gyeongbuk-do, 39660, South Korea
| | - Ki-Sun Kim
- Virus Disease Division, Animal and Plant Quarantine Agency, Gimchen, Gyeongbuk-do, 39660, South Korea
| | - Hye-Young Jeoung
- Virus Disease Division, Animal and Plant Quarantine Agency, Gimchen, Gyeongbuk-do, 39660, South Korea
| | - Ra Mi Cha
- Virus Disease Division, Animal and Plant Quarantine Agency, Gimchen, Gyeongbuk-do, 39660, South Korea
| | - Gil-Soon Park
- Virus Disease Division, Animal and Plant Quarantine Agency, Gimchen, Gyeongbuk-do, 39660, South Korea
| | - Jihye Shin
- Virus Disease Division, Animal and Plant Quarantine Agency, Gimchen, Gyeongbuk-do, 39660, South Korea
| | - Gyu-Nam Park
- Virus Disease Division, Animal and Plant Quarantine Agency, Gimchen, Gyeongbuk-do, 39660, South Korea
| | - In-Soo Cho
- Virus Disease Division, Animal and Plant Quarantine Agency, Gimchen, Gyeongbuk-do, 39660, South Korea
| | - Jae-Young Song
- Virus Disease Division, Animal and Plant Quarantine Agency, Gimchen, Gyeongbuk-do, 39660, South Korea
| | - Bang-Hun Hyun
- Virus Disease Division, Animal and Plant Quarantine Agency, Gimchen, Gyeongbuk-do, 39660, South Korea
| | - Bong-Kyun Park
- Virus Disease Division, Animal and Plant Quarantine Agency, Gimchen, Gyeongbuk-do, 39660, South Korea; College of Veterinary Medicine, Seoul University, Gwanak-ro, Gwanak-gu, Seoul 08826, South Korea
| | - Dong-Jun An
- Virus Disease Division, Animal and Plant Quarantine Agency, Gimchen, Gyeongbuk-do, 39660, South Korea.
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Li Y, Xie L, Zhang L, Wang X, Li C, Han Y, Hu S, Sun Y, Li S, Luo Y, Liu L, Munir M, Qiu HJ. The E2 glycoprotein is necessary but not sufficient for the adaptation of classical swine fever virus lapinized vaccine C-strain to the rabbit. Virology 2018; 519:197-206. [PMID: 29734043 DOI: 10.1016/j.virol.2018.04.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 04/14/2018] [Accepted: 04/21/2018] [Indexed: 12/26/2022]
Abstract
Classical swine fever virus (CSFV) C-strain was developed through hundreds of passages of a highly virulent CSFV in rabbits. To investigate the molecular basis for the adaptation of C-strain to the rabbit (ACR), a panel of chimeric viruses with the exchange of glycoproteins Erns, E1, and/or E2 between C-strain and the highly virulent Shimen strain and a number of mutant viruses with different amino acid substitutions in E2 protein were generated and evaluated in rabbits. Our results demonstrate that Shimen-based chimeras expressing Erns-E1-E2, Erns-E2 or E1-E2 but not Erns-E1, Erns, E1, or E2 of C-strain can replicate in rabbits, indicating that E2 in combination with either Erns or E1 confers the ACR. Notably, E2 and the amino acids P108 and T109 in Domain I of E2 are critical in ACR. Collectively, our data indicate that E2 is crucial in mediating the ACR, which requires synergistic contribution of Erns or E1.
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Affiliation(s)
- Yongfeng Li
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Libao Xie
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Lingkai Zhang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Xiao Wang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Chao Li
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Yuying Han
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Shouping Hu
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Yuan Sun
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Su Li
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Yuzi Luo
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Lihong Liu
- Department of Microbiology, National Veterinary Institute (SVA), Uppsala, Sweden
| | - Muhammad Munir
- Division of Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, United Kingdom
| | - Hua-Ji Qiu
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China.
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10
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Culling vs. emergency vaccination: A comparative economic evaluation of strategies for controlling classical swine fever in the EU. Livest Sci 2018. [DOI: 10.1016/j.livsci.2017.11.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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11
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Blome S, Wernike K, Reimann I, König P, Moß C, Beer M. A decade of research into classical swine fever marker vaccine CP7_E2alf (Suvaxyn ® CSF Marker): a review of vaccine properties. Vet Res 2017; 48:51. [PMID: 28915927 PMCID: PMC5603031 DOI: 10.1186/s13567-017-0457-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Accepted: 09/04/2017] [Indexed: 11/29/2022] Open
Abstract
Due to its impact on animal health and pig industry, classical swine fever (CSF) is still one of the most important viral diseases of pigs. To control the disease, safe and highly efficacious live attenuated vaccines exist for decades. However, until recently, the available live vaccines did not allow a serological marker concept that is essentially important to circumvent long-term trade restrictions. In 2014, a new live attenuated marker vaccine, Suvaxyn® CSF Marker (Zoetis), was licensed by the European Medicines Agency. This vaccine is based on pestivirus chimera “CP7_E2alf” that carries the main immunogen of CSF virus “Alfort/187”, glycoprotein E2, in a bovine viral diarrhea virus type 1 backbone (“CP7”). This review summarizes the available data on design, safety, efficacy, marker diagnostics, and its possible integration into control strategies.
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Affiliation(s)
- Sandra Blome
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Suedufer 10, 17493, Greifswald-Insel Riems, Germany.
| | - Kerstin Wernike
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Suedufer 10, 17493, Greifswald-Insel Riems, Germany
| | - Ilona Reimann
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Suedufer 10, 17493, Greifswald-Insel Riems, Germany
| | - Patricia König
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Suedufer 10, 17493, Greifswald-Insel Riems, Germany
| | - Claudia Moß
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Suedufer 10, 17493, Greifswald-Insel Riems, Germany
| | - Martin Beer
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Suedufer 10, 17493, Greifswald-Insel Riems, Germany
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Postel A, Austermann-Busch S, Petrov A, Moennig V, Becher P. Epidemiology, diagnosis and control of classical swine fever: Recent developments and future challenges. Transbound Emerg Dis 2017; 65 Suppl 1:248-261. [PMID: 28795533 DOI: 10.1111/tbed.12676] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Indexed: 12/31/2022]
Abstract
Classical swine fever (CSF) represents a major health and trade problem for the pig industry. In endemic countries or those with a wild boar reservoir, CSF remains a priority for Veterinary Services. Surveillance as well as stamping out and/or vaccination are the principle tools of prevention and control, depending on the context. In the past decades, marker vaccines and accompanying diagnostic tests allowing the discrimination of infected from vaccinated animals have been developed. In the European Union, an E2 subunit and a chimeric live vaccine have been licensed and are available for the use in future disease outbreak scenarios. The implementation of commonly accepted and globally harmonized concepts could pave the way to replace the ethically questionable stamping out policy by a vaccination-to-live strategy and thereby avoid culling of a large number of healthy animals and save food resources. Although a number of vaccines and diagnostic tests are available worldwide, technological advancement in both domains is desirable. This work provides a summary of an analysis undertaken by the DISCONTOOLS group of experts on CSF. Details of the analysis can be downloaded from the web site at http://www.discontools.eu/.
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Affiliation(s)
- Alexander Postel
- EU and OIE Reference Laboratory for Classical Swine Fever, Department of Infectious Diseases, Institute of Virology, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Sophia Austermann-Busch
- EU and OIE Reference Laboratory for Classical Swine Fever, Department of Infectious Diseases, Institute of Virology, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Anja Petrov
- EU and OIE Reference Laboratory for Classical Swine Fever, Department of Infectious Diseases, Institute of Virology, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Volker Moennig
- EU and OIE Reference Laboratory for Classical Swine Fever, Department of Infectious Diseases, Institute of Virology, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Paul Becher
- EU and OIE Reference Laboratory for Classical Swine Fever, Department of Infectious Diseases, Institute of Virology, University of Veterinary Medicine Hannover, Hannover, Germany
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Classical Swine Fever-An Updated Review. Viruses 2017; 9:v9040086. [PMID: 28430168 PMCID: PMC5408692 DOI: 10.3390/v9040086] [Citation(s) in RCA: 156] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 04/11/2017] [Accepted: 04/13/2017] [Indexed: 01/03/2023] Open
Abstract
Classical swine fever (CSF) remains one of the most important transboundary viral diseases of swine worldwide. The causative agent is CSF virus, a small, enveloped RNA virus of the genus Pestivirus. Based on partial sequences, three genotypes can be distinguished that do not, however, directly correlate with virulence. Depending on both virus and host factors, a wide range of clinical syndromes can be observed and thus, laboratory confirmation is mandatory. To this means, both direct and indirect methods are utilized with an increasing degree of commercialization. Both infections in domestic pigs and wild boar are of great relevance; and wild boars are a reservoir host transmitting the virus sporadically also to pig farms. Control strategies for epidemic outbreaks in free countries are mainly based on classical intervention measures; i.e., quarantine and strict culling of affected herds. In these countries, vaccination is only an emergency option. However, live vaccines are used for controlling the disease in endemically infected regions in Asia, Eastern Europe, the Americas, and some African countries. Here, we will provide a concise, updated review on virus properties, clinical signs and pathology, epidemiology, pathogenesis and immune responses, diagnosis and vaccination possibilities.
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Rose N, Andraud M. The use of vaccines to control pathogen spread in pig populations. Porcine Health Manag 2017; 3:8. [PMID: 28405464 PMCID: PMC5382368 DOI: 10.1186/s40813-017-0053-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 02/08/2017] [Indexed: 01/13/2023] Open
Abstract
Vaccine efficacy has often been studied from the viewpoint of individual direct clinical protection. For several vaccines, a decrease in pathogen shedding in vaccinated animals has also been documented, which suggests that transmission between individuals has the potential to be reduced. In addition, vaccination induces an immune response in the host potentially decreasing susceptibility to infection in comparison with immunologically naïve animals. As a collective result of individual vaccinations, vaccine programmes generally have a wider impact on pathogen diffusion at the population scale. Beyond the individual protection conferred by mass vaccination campaigns, the indirect protection of non-immune individuals in contact with vaccinated ones also contributes to controlling pathogen spread at the population scale; a phenomenon known as herd immunity. Pathogen spread within pig populations is strongly related to the required vaccine coverage at the population level and to pathogen characteristics in terms of diffusion (\documentclass[12pt]{minimal}
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\begin{document}$$ {R}_0 $$\end{document}R0). Before setting up vaccination programmes, it is therefore necessary to have quantitative knowledge on vaccine efficacy as regards transmission reduction. These data can be obtained by carrying out experimental studies or observational protocols in real conditions. These quantitative data have mainly been estimated for major infectious diseases which have now been eradicated. A great gap in knowledge has however been identified for enzootic diseases which are daily impacting the swine sector as well as for the source of variation responsible for a decrease in vaccine efficacy as compared to assessments obtained in experimental conditions.
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Affiliation(s)
- Nicolas Rose
- Anses-Laboratoire de Ploufragan-Plouzané, Swine Epidemiology and Welfare Research Unit, Po Box 53, F22440 Ploufragan, France ; Université Bretagne Loire, Rennes, France
| | - Mathieu Andraud
- Anses-Laboratoire de Ploufragan-Plouzané, Swine Epidemiology and Welfare Research Unit, Po Box 53, F22440 Ploufragan, France ; Université Bretagne Loire, Rennes, France
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Meyer D, Fritsche S, Luo Y, Engemann C, Blome S, Beyerbach M, Chang CY, Qiu HJ, Becher P, Postel A. The double-antigen ELISA concept for early detection of E rns -specific classical swine fever virus antibodies and application as an accompanying test for differentiation of infected from marker vaccinated animals. Transbound Emerg Dis 2017; 64:2013-2022. [PMID: 28158921 DOI: 10.1111/tbed.12611] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Indexed: 11/30/2022]
Abstract
Emergency vaccination with live marker vaccines represents a promising control strategy for future classical swine fever (CSF) outbreaks, and the first live marker vaccine is available in Europe. Successful implementation is dependent on a reliable accompanying diagnostic assay that allows differentiation of infected from vaccinated animals (DIVA). As induction of a protective immune response relies on virus-neutralizing antibodies against E2 protein of CSF virus (CSFV), the most promising DIVA strategy is based on detection of Erns -specific antibodies in infected swine. The aim of this study was to develop and to evaluate a novel Erns -specific prototype ELISA (pigtype CSFV Erns Ab), which may be used for CSF diagnosis including application as an accompanying discriminatory test for CSFV marker vaccines. The concept of a double-antigen ELISA was shown to be a solid strategy to detect Erns -specific antibodies against CSFV isolates of different genotypes (sensitivity: 93.5%; specificity: 99.7%). Furthermore, detection of early seroconversion is advantageous compared with a frequently used CSFV E2 antibody ELISA. Clear differences in reactivity between sera taken from infected animals and animals vaccinated with various marker vaccines were observed. In combination with the marker vaccine CP7_E2alf, the novel ELISA represents a sensitivity of 90.2% and a specificity of 93.8%. However, cross-reactivity with antibodies against ruminant pestiviruses was observed. Interestingly, the majority of samples tested false-positive in other Erns -based antibody ELISAs were identified correctly by the novel prototype Erns ELISA and vice versa. In conclusion, the pigtype CSFV Erns Ab ELISA can contribute to an improvement in routine CSFV antibody screening, particularly for analysis of sera taken at an early time point after infection and is applicable as a DIVA assay. An additional Erns antibody assay is recommended for identification of false-positive results in a pig herd immunized with the licensed CP7_E2alf marker vaccine.
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Affiliation(s)
- D Meyer
- EU and OIE Reference Laboratory for Classical Swine Fever, Institute of Virology, Department of Infectious Diseases, University of Veterinary Medicine Hannover, Hannover, Germany
| | | | - Y Luo
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute (HVRI), Chinese Academy of Agricultural Sciences, Harbin, China
| | | | - S Blome
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Greifswald, Germany
| | - M Beyerbach
- Institute for Biometry, Epidemiology and Information Processing, University of Veterinary Medicine Hannover, Hannover, Germany
| | - C-Y Chang
- Animal Health Research Institute, Council of Agriculture, Executive Yuan, Tamsui District, New Taipei City, Taiwan
| | - H-J Qiu
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute (HVRI), Chinese Academy of Agricultural Sciences, Harbin, China
| | - P Becher
- EU and OIE Reference Laboratory for Classical Swine Fever, Institute of Virology, Department of Infectious Diseases, University of Veterinary Medicine Hannover, Hannover, Germany
| | - A Postel
- EU and OIE Reference Laboratory for Classical Swine Fever, Institute of Virology, Department of Infectious Diseases, University of Veterinary Medicine Hannover, Hannover, Germany
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16
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Madera R, Gong W, Wang L, Burakova Y, Lleellish K, Galliher-Beckley A, Nietfeld J, Henningson J, Jia K, Li P, Bai J, Schlup J, McVey S, Tu C, Shi J. Pigs immunized with a novel E2 subunit vaccine are protected from subgenotype heterologous classical swine fever virus challenge. BMC Vet Res 2016; 12:197. [PMID: 27612954 PMCID: PMC5016919 DOI: 10.1186/s12917-016-0823-4] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 09/01/2016] [Indexed: 11/17/2022] Open
Abstract
Background Classical swine fever (CSF) or hog cholera is a highly contagious swine viral disease. CSF endemic countries have to use routine vaccination with modified live virus (MLV) vaccines to prevent and control CSF. However, it is impossible to serologically differentiate MLV vaccinated pigs from those infected with CSF virus (CSFV). The aim of this study is to develop a one-dose E2-subunit vaccine that can provide protection against CSFV challenge. We hypothesize that a vaccine consisting of a suitable adjuvant and recombinant E2 with natural conformation may induce a similar level of protection as the MLV vaccine. Results Our experimental vaccine KNB-E2 was formulated with the recombinant E2 protein (Genotype 1.1) expressed by insect cells and an oil-in-water emulsion based adjuvant. 10 pigs (3 weeks old, 5 pigs/group) were immunized intramuscularly with one dose or two doses (3 weeks apart) KNB-E2, and 10 more control pigs were administered normal saline solution only. Two weeks after the second vaccination, all KNB-E2 vaccinated pigs and 5 control pigs were challenged with 5 × 105 TCID50 CSFV Honduras/1997 (Genotype 1.3, 1 ml intramuscular, 1 ml intranasal). It was found that while control pigs infected with CSFV stopped growing and developed high fever (>40 °C), high level CSFV load in blood and nasal fluid, and severe leukopenia 3–14 days post challenge, all KNB-E2 vaccinated pigs continued to grow as control pigs without CSFV exposure, did not show any fever, had low or undetectable level of CSFV in blood and nasal fluid. At the time of CSFV challenge, only pigs immunized with KNB-E2 developed high levels of E2-specific antibodies and anti-CSFV neutralizing antibodies. Conclusions Our studies provide direct evidence that pigs immunized with one dose KNB-E2 can be protected clinically from CSFV challenge. This protection is likely mediated by high levels of E2-specific and anti-CSFV neutralizing antibodies.
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Affiliation(s)
- Rachel Madera
- Department of Anatomy and Physiology, Kansas State University, Manhattan, KS, 66506, USA
| | - Wenjie Gong
- Department of Anatomy and Physiology, Kansas State University, Manhattan, KS, 66506, USA.,Institute of Military Veterinary Medicine, Academy of Military Medical Sciences, Changchun, China
| | - Lihua Wang
- Department of Anatomy and Physiology, Kansas State University, Manhattan, KS, 66506, USA
| | - Yulia Burakova
- Department of Anatomy and Physiology, Kansas State University, Manhattan, KS, 66506, USA.,Department of Chemical Engineering, Kansas State University, Manhattan, KS, 66506, USA
| | - Karen Lleellish
- Department of Anatomy and Physiology, Kansas State University, Manhattan, KS, 66506, USA
| | - Amy Galliher-Beckley
- Department of Anatomy and Physiology, Kansas State University, Manhattan, KS, 66506, USA
| | - Jerome Nietfeld
- Department of Diagnostic Medicine and Pathobiology, Kansas State University, Manhattan, KS, 66506, USA
| | - Jamie Henningson
- Department of Diagnostic Medicine and Pathobiology, Kansas State University, Manhattan, KS, 66506, USA
| | - Kaimin Jia
- Department of Chemistry, Kansas State University, Manhattan, KS, 66506, USA
| | - Ping Li
- Department of Chemistry, Kansas State University, Manhattan, KS, 66506, USA
| | - Jianfa Bai
- Department of Diagnostic Medicine and Pathobiology, Kansas State University, Manhattan, KS, 66506, USA
| | - John Schlup
- Department of Chemical Engineering, Kansas State University, Manhattan, KS, 66506, USA
| | - Scott McVey
- United States Department of Agriculture, Agricultural Research Service, Arthropod Borne Animal Disease Research Unit, Manhattan, KS, 66502, USA
| | - Changchun Tu
- Institute of Military Veterinary Medicine, Academy of Military Medical Sciences, Changchun, China.
| | - Jishu Shi
- Department of Anatomy and Physiology, Kansas State University, Manhattan, KS, 66506, USA.
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17
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Goller KV, Dräger C, Höper D, Beer M, Blome S. Classical swine fever virus marker vaccine strain CP7_E2alf: genetic stability in vitro and in vivo. Arch Virol 2015; 160:3121-5. [PMID: 26392285 DOI: 10.1007/s00705-015-2611-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 09/11/2015] [Indexed: 10/23/2022]
Abstract
Recently, CP7_E2alf (SuvaxynCSF Marker), a live marker vaccine against classical swine fever virus, was licensed through the European Medicines Agency. For application of such a genetically engineered virus under field conditions, knowledge about its genetic stability is essential. Here, we report on stability studies that were conducted to assess and compare the mutation rate of CP7_E2alf in vitro and in vivo. Sequence analyses upon passaging confirmed the high stability of CP7_E2alf, and no recombination events were observed in the experimental setup. The data obtained in this study confirm the genetic stability of CP7_E2alf as an important safety component.
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Affiliation(s)
- Katja V Goller
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Suedufer 10, 17493, Greifswald, Insel Riems, Germany
| | - Carolin Dräger
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Suedufer 10, 17493, Greifswald, Insel Riems, Germany
| | - Dirk Höper
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Suedufer 10, 17493, Greifswald, Insel Riems, Germany
| | - Martin Beer
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Suedufer 10, 17493, Greifswald, Insel Riems, Germany
| | - Sandra Blome
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Suedufer 10, 17493, Greifswald, Insel Riems, Germany.
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18
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Pannhorst K, Fröhlich A, Staubach C, Meyer D, Blome S, Becher P. Evaluation of an Erns-based enzyme-linked immunosorbent assay to distinguish Classical swine fever virus-infected pigs from pigs vaccinated with CP7_E2alf. J Vet Diagn Invest 2015; 27:449-60. [PMID: 26179095 DOI: 10.1177/1040638715592446] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Infections with Classical swine fever virus (CSFV) are a major economic threat to pig production. To combat CSF outbreaks and to maintain trade, new marker vaccines were developed that allow differentiation of infected from vaccinated animals (DIVA principle). The chimeric pestivirus CP7_E2alf was shown to be safe and efficacious. Its DIVA strategy is based on the detection of CSFV E(rns)-specific antibodies that are only developed on infection. However, for the new marker vaccine to be considered a valuable control tool, a validated discriminatory assay is needed. One promising candidate is the already commercially available enzyme-linked immunosorbent assay, PrioCHECK CSFV E(rns) ELISA (Prionics BV, Lelystad, The Netherlands). Four laboratories of different European Union member states tested 530 serum samples and country-specific field sera from domestic pigs and wild boar. The ELISA displayed a good robustness. However, based on its reproducibility and repeatability, ranges rather than single values for diagnostic sensitivity and specificity were defined. The ELISA displayed a sensitivity of 90-98% with sera from CSFV-infected domestic pigs. A specificity of 89-96% was calculated with sera from domestic pigs vaccinated once with CP7_E2alf. The ELISA detected CSFV infections in vaccinated domestic pigs with a sensitivity of 82-94%. The sensitivity was lower with sera taken ≤21 days post-challenge indicating that the stage of CSFV infection had a considerable influence on testing. Taken together, the PrioCHECK CSFV E(rns) ELISA can be used for detection of CSFV infections in CP7_E2alf-vaccinated and nonvaccinated domestic pig populations, but should only be applied on a herd basis by testing a defined number of animals.
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Affiliation(s)
- Katrin Pannhorst
- Institute of Virology, Department of Infectious Diseases, University of Veterinary Medicine, Hannover, Germany (Pannhorst, Meyer, Becher)Institute of Epidemiology (Fröhlich, Staubach)Institute of Diagnostic Virology (Blome)Friedrich-Loeffler-Institut, Greifswald, Insel Riems, Germany
| | - Andreas Fröhlich
- Institute of Virology, Department of Infectious Diseases, University of Veterinary Medicine, Hannover, Germany (Pannhorst, Meyer, Becher)Institute of Epidemiology (Fröhlich, Staubach)Institute of Diagnostic Virology (Blome)Friedrich-Loeffler-Institut, Greifswald, Insel Riems, Germany
| | - Christoph Staubach
- Institute of Virology, Department of Infectious Diseases, University of Veterinary Medicine, Hannover, Germany (Pannhorst, Meyer, Becher)Institute of Epidemiology (Fröhlich, Staubach)Institute of Diagnostic Virology (Blome)Friedrich-Loeffler-Institut, Greifswald, Insel Riems, Germany
| | - Denise Meyer
- Institute of Virology, Department of Infectious Diseases, University of Veterinary Medicine, Hannover, Germany (Pannhorst, Meyer, Becher)Institute of Epidemiology (Fröhlich, Staubach)Institute of Diagnostic Virology (Blome)Friedrich-Loeffler-Institut, Greifswald, Insel Riems, Germany
| | - Sandra Blome
- Institute of Virology, Department of Infectious Diseases, University of Veterinary Medicine, Hannover, Germany (Pannhorst, Meyer, Becher)Institute of Epidemiology (Fröhlich, Staubach)Institute of Diagnostic Virology (Blome)Friedrich-Loeffler-Institut, Greifswald, Insel Riems, Germany
| | - Paul Becher
- Institute of Virology, Department of Infectious Diseases, University of Veterinary Medicine, Hannover, Germany (Pannhorst, Meyer, Becher)Institute of Epidemiology (Fröhlich, Staubach)Institute of Diagnostic Virology (Blome)Friedrich-Loeffler-Institut, Greifswald, Insel Riems, Germany
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19
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Thioredoxin 2 Is a Novel E2-Interacting Protein That Inhibits the Replication of Classical Swine Fever Virus. J Virol 2015; 89:8510-24. [PMID: 26041303 DOI: 10.1128/jvi.00429-15] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Accepted: 05/29/2015] [Indexed: 02/07/2023] Open
Abstract
UNLABELLED The E2 protein of classical swine fever virus (CSFV) is an envelope glycoprotein that is involved in virus attachment and entry. To date, the E2-interacting cellular proteins and their involvement in viral replication have been poorly documented. In this study, thioredoxin 2 (Trx2) was identified to be a novel E2-interacting partner using yeast two-hybrid screening from a porcine macrophage cDNA library. Trx2 is a mitochondrion-associated protein that participates in diverse cellular events. The Trx2-E2 interaction was further confirmed by glutathione S-transferase (GST) pulldown, in situ proximity ligation, and laser confocal assays. The thioredoxin domain of Trx2 and the asparagine at position 37 (N37) in the E2 protein were shown to be critical for the interaction. Silencing of the Trx2 expression in PK-15 cells by small interfering RNAs significantly promotes CSFV replication, and conversely, overexpression of Trx2 markedly inhibits viral replication of the wild-type (wt) CSFV and to a greater extent that of the CSFV N37D mutant, which is defective in binding Trx2. The wt CSFV but not the CSFV N37D mutant was shown to reduce the Trx2 protein expression in PK-15 cells. Furthermore, we demonstrated that Trx2 increases nuclear factor kappa B (NF-κB) promoter activity by promoting the nuclear translocation of the p65 subunit of NF-κB. Notably, activation of the NF-κB signaling pathway induced by tumor necrosis factor alpha (TNF-α) significantly inhibits CSFV replication in PK-15 cells, whereas blocking the NF-κB activation in Trx2-overexpressing cells no longer suppresses CSFV replication. Taken together, our findings reveal that Trx2 inhibits CSFV replication via the NF-κB signaling pathway. IMPORTANCE Thioredoxin 2 (Trx2) is a mitochondrion-associated protein that participates in diverse cellular events, such as antioxidative and antiapoptotic processes and the modulation of transcription factors. However, little is known about the involvement of Trx2 in viral replication. Here, we investigated, for the first time, the role of Trx2 in the replication of classical swine fever virus (CSFV), a devastating pestivirus of pigs. By knockdown and overexpression, we showed that Trx2 negatively regulates CSFV replication. Notably, we demonstrated that Trx2 inhibits CSFV replication by promoting the nuclear translocation of the p65 subunit of NF-κB, a key regulator of the host's innate immunity and inflammatory response. Our findings reveal a novel role of Trx2 in the host's antiviral response and provide new insights into the complex mechanisms by which CSFV interacts with the host cell.
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20
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Bruderer U, van de Velde J, Frantzen I, De Bortoli F. Discrimination within epitope specific antibody populations against Classical swine fever virus is a new means of differentiating infection from vaccination. J Immunol Methods 2015; 420:18-23. [PMID: 25825375 DOI: 10.1016/j.jim.2015.03.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 03/18/2015] [Accepted: 03/18/2015] [Indexed: 10/23/2022]
Abstract
Serological differentiation between infection and vaccination depends on the detection of pathogen specific antibodies for an epitope that is modified or lacking in a vaccine. Here we describe a new assay principle that is based on differences in the binding properties of epitope specific antibodies. C-DIVA is a potent Classical swine fever vaccine candidate that differs from the parental C-strain life attenuated vaccine in the highly immunogenic TAVSPTTLR epitope by the deletion of two and the mutation of one amino acid (TAGSΔΔTLR). We show that C-DIVA vaccination elicits antibodies with high affinity for both the TAGSΔΔTLR and TAVSPTTLR epitope, whereas infection elicits only TAVSPTTLR specific antibodies. Differentiation is achieved with a double competition assay with negative selection for antibodies with affinity for the TAGSΔΔTLR epitope followed by positive selection for antibodies with affinity for the TAVSPTTLR epitope. Our findings add a new strategy for the development of marker vaccines and their accompanying discrimination assays and offer an alternative to the devastating stamping out policy for Classical swine fever.
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Affiliation(s)
- Urs Bruderer
- Discovery & Technology Vaccine Analysis, MSD Animal Health, Boxmeer, The Netherlands.
| | - Jan van de Velde
- Discovery & Technology Vaccine Analysis, MSD Animal Health, Boxmeer, The Netherlands
| | - Inge Frantzen
- Discovery & Technology Expression, MSD Animal Health, Boxmeer, The Netherlands
| | - Francesca De Bortoli
- Institute of Chemistry and Biochemistry, Free University of Berlin, Berlin, Germany
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21
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Everett HE, Crudgington BS, Sosan-Soulé O, Crooke HR. Differential detection of classical swine fever virus challenge strains in C-strain vaccinated pigs. BMC Vet Res 2014; 10:281. [PMID: 25495277 PMCID: PMC4280032 DOI: 10.1186/s12917-014-0281-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Accepted: 11/14/2014] [Indexed: 11/10/2022] Open
Abstract
Background Control of classical swine fever (CSF) by vaccination ideally requires that field strain infection can be detected irrespective of the vaccination status of the herd. To inform on the usefulness of molecular tests compatible with genetic Differentiation of Infected from Vaccinated Animals (DIVA) principles when using live-attenuated vaccines, tonsil homogenates from a vaccination-challenge experiment were analyzed using a differential real-time qRT-PCR for the C-strain vaccine or real-time qRT-PCR assays developed to specifically detect the challenge strains used. Results In animals with high or moderate levels of blood viraemia, which were not, or not fully, protected by vaccination, challenge virus RNA was readily detected in tonsil homogenates. In three out of the seven vaccinated animals that had high or moderate viraemia, the vaccine strain RNA also could be detected but at lower levels. Lower but varying levels of challenge and/or vaccine virus RNA were detected in tonsil homogenate samples from animals with no or low-level viraemia, and in groups solely consisting of such animals, no transmission of infection to naïve in-contact animals occurred. In one group of animals that were vaccinated 3 days prior to challenge, viraemia levels varied from high to absent and transmission of challenge virus to naïve in-contact animals occurred. The DIVA assay revealed challenge virus in all tonsil homogenates from this group, even in those animals that did not have viraemia and were protected from clinical disease by vaccination. Such animals, particularly in a low biosecurity/informal farm setting, could constitute a risk for disease control in the field. Conclusions Genetic DIVA testing is useful for detecting the presence of field virus infection especially in non-viraemic animals without overt clinical signs but which are incompletely protected by vaccination. Such tests could particularly be useful to inform decisions prior to and during cessation of a control strategy that employs vaccination.
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Affiliation(s)
- Helen E Everett
- Virology Department, APHA, New Haw, Addlestone, KT15 3NB, UK.
| | | | | | - Helen R Crooke
- Virology Department, APHA, New Haw, Addlestone, KT15 3NB, UK.
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22
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Abstract
The advent of reverse genetic approaches to manipulate the genomes of both positive (+) and negative (-) sense RNA viruses allowed researchers to harness these genomes for basic research. Manipulation of positive sense RNA virus genomes occurred first largely because infectious RNA could be transcribed directly from cDNA versions of the RNA genomes. Manipulation of negative strand RNA virus genomes rapidly followed as more sophisticated approaches to provide RNA-dependent RNA polymerase complexes coupled with negative-strand RNA templates were developed. These advances have driven an explosion of RNA virus vaccine vector development. That is, development of approaches to exploit the basic replication and expression strategies of RNA viruses to produce vaccine antigens that have been engineered into their genomes. This study has led to significant preclinical testing of many RNA virus vectors against a wide range of pathogens as well as cancer targets. Multiple RNA virus vectors have advanced through preclinical testing to human clinical evaluation. This review will focus on RNA virus vectors designed to express heterologous genes that are packaged into viral particles and have progressed to clinical testing.
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Affiliation(s)
- Mark A Mogler
- Harrisvaccines, Inc., 1102 Southern Hills Drive, Suite 101, Ames, IA 50010, USA
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Differentiation of classical swine fever virus infection from CP7_E2alf marker vaccination by a multiplex microsphere immunoassay. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2014; 22:65-71. [PMID: 25378351 DOI: 10.1128/cvi.00271-14] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Classical swine fever (CSF) is a highly contagious viral disease of pigs that has a tremendous socioeconomic impact. Vaccines are available for disease control. However, most industrialized countries are implementing stamping-out strategies to eliminate the disease and avoid trade restrictions. These restrictions can be avoided through the use of marker vaccines such as CP7_E2alf. Marker vaccines have to be accompanied by reliable and robust discriminatory assays. In this context, a multiplex microsphere immunoassay for serological differentiation of infected from vaccinated animals (DIVA) was developed to distinguish CSF virus (CSFV)-infected animals from CP7_E2alf-vaccinated animals. To this end, three viral proteins, namely, CSFV E2, CSFV E(rns), and bovine viral diarrhea virus (BVDV) E2, were produced in insect cells using a baculovirus expression system; they were used as antigens in a microsphere immunoassay, which was further evaluated by testing a large panel of pig sera and compared to a well-characterized commercial CSFV E2 antibody enzyme-linked immunosorbent assays (ELISAs) and a test version of an improved CSFV E(rns) antibody ELISA. Under a cutoff median fluorescence intensity value of 5,522, the multiplex microsphere immunoassay had a sensitivity of 98.5% and a specificity of 98.9% for the detection of antibodies against CSFV E2. The microsphere immunoassay and the CSFV E(rns) ELISA gave the same results for 155 out of 187 samples (82.8%) for the presence of CSFV E(rns) antibodies. This novel multiplex immunoassay is a valuable tool for measuring and differentiating immune responses to vaccination and/or infection in animals.
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Eblé PL, Quak S, Geurts Y, Moonen-Leusen HWM, Loeffen WLA. Efficacy of CSF vaccine CP7_E2alf in piglets with maternally derived antibodies. Vet Microbiol 2014; 174:27-38. [PMID: 25265929 DOI: 10.1016/j.vetmic.2014.08.030] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 08/06/2014] [Accepted: 08/26/2014] [Indexed: 11/25/2022]
Abstract
There is a need for live DIVA (differentiating infected from vaccinated animals) vaccines against classical swine fever (CSF). The aim of this study was to investigate whether vaccination with the chimeric pestivirus vaccine CP7_E2alf is efficacious to protect young piglets born from vaccinated sows, thus with maternally derived antibodies (MDAs). Groups of 10 piglets each, with or without MDAs, were vaccinated either intramuscularly (IM), at an age of 3 or 6 weeks, or orally (OR), at an age of 6 weeks. Five piglets of each group were challenged with CSFV strain Koslov and protection against clinical disease, virus shedding and transmission were studied. Vaccination with CP7_E2alf, both in the presence of MDA's and in piglets without MDA's, protected against severe clinical signs, but virus shedding from most inoculated piglets and transmission to contact pigs was observed. However, virus transmission in the vaccinated piglets was significantly reduced as compared to non-vaccinated piglets, although the reproduction ratio's R calculated from the results in the vaccinated pigs from our study were not yet significantly below 1. The efficacy of vaccination with CP7_E2alf in the presence of MDAs (R IMvac=0.8, R ORvac=0.4) seemed to be slightly less as compared to vaccination in the absence of MDAs (R IMvac=0.2, R ORvac=0). On a population level, the results suggest that the CP7_E2alf vaccine is an effective tool in the control and eradication of CSF and, moreover, can be applied for both IM and oral use for young age groups, with MDAs having a limited effect on the efficacy.
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Affiliation(s)
- P L Eblé
- Central Veterinary Institute of Wageningen UR (CVI), P.O. Box 65, 8200 AB Lelystad, The Netherlands
| | - S Quak
- Central Veterinary Institute of Wageningen UR (CVI), P.O. Box 65, 8200 AB Lelystad, The Netherlands
| | - Y Geurts
- Central Veterinary Institute of Wageningen UR (CVI), P.O. Box 65, 8200 AB Lelystad, The Netherlands
| | - H W M Moonen-Leusen
- Central Veterinary Institute of Wageningen UR (CVI), P.O. Box 65, 8200 AB Lelystad, The Netherlands
| | - W L A Loeffen
- Central Veterinary Institute of Wageningen UR (CVI), P.O. Box 65, 8200 AB Lelystad, The Netherlands.
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First assessment of classical swine fever marker vaccine candidate CP7_E2alf for oral immunization of wild boar under field conditions. Vaccine 2014; 32:2050-5. [DOI: 10.1016/j.vaccine.2014.02.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Revised: 01/31/2014] [Accepted: 02/06/2014] [Indexed: 11/21/2022]
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Blome S, Gabriel C, Schmeiser S, Meyer D, Meindl-Böhmer A, Koenen F, Beer M. Efficacy of marker vaccine candidate CP7_E2alf against challenge with classical swine fever virus isolates of different genotypes. Vet Microbiol 2013; 169:8-17. [PMID: 24411658 DOI: 10.1016/j.vetmic.2013.12.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Revised: 11/30/2013] [Accepted: 12/02/2013] [Indexed: 10/25/2022]
Abstract
Classical swine fever (CSF) is among the most important viral disease of domestic and feral pigs and has a serious impact on animal health and pig industry. In most countries with industrialized pig production, prophylactic vaccination against CSF is banned, and all efforts are directed towards eradication of the disease, e.g. by culling of infected herds and animal movement restrictions. Nevertheless, emergency vaccination remains an option to minimize the socio-economic impact of outbreaks. For this application, potent vaccines are needed that allow differentiation of infected from vaccinated animals. Among the promising candidates for next generation marker vaccines is the chimeric pestivirus CP7_E2alf. Efficacy studies are usually carried out using highly virulent CSFV strains of genotype 1 that do not mirror the current field situation where strains of genotype 2 predominate. To prove that CP7_E2alf also protects against these strains, efficacy was assessed after single oral vaccination of wild boar and single intramuscular vaccination of domestic pigs using challenge models with recent CSFV strains and the highly virulent strain "Koslov" (genotype 1.1). It could be demonstrated that CP7_E2alf pilot vaccine batches for intramuscular and oral use were able to protect pigs from challenge infection with a highly virulent CSFV. Moreover, solid protection was also achieved in case of challenge infection with recent field strains of genotypes 2.1 and 2.3. Thus, broad applicability under field conditions can be assumed.
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Affiliation(s)
- Sandra Blome
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Suedufer 10, 17493 Greifswald - Insel Riems, Germany.
| | - Claudia Gabriel
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Suedufer 10, 17493 Greifswald - Insel Riems, Germany
| | - Stefanie Schmeiser
- European Union Reference Laboratory for CSF, Institute of Virology, Department of Infectious Diseases, University of Veterinary Medicine Hannover, Buenteweg 17, 30559 Hannover, Germany
| | - Denise Meyer
- European Union Reference Laboratory for CSF, Institute of Virology, Department of Infectious Diseases, University of Veterinary Medicine Hannover, Buenteweg 17, 30559 Hannover, Germany
| | - Alexandra Meindl-Böhmer
- European Union Reference Laboratory for CSF, Institute of Virology, Department of Infectious Diseases, University of Veterinary Medicine Hannover, Buenteweg 17, 30559 Hannover, Germany
| | - Frank Koenen
- CODA-CERVA, Groeselenberg 99, 1180 Ukkel, Belgium
| | - Martin Beer
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Suedufer 10, 17493 Greifswald - Insel Riems, Germany
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Newcomer BW, Givens MD. Approved and experimental countermeasures against pestiviral diseases: Bovine viral diarrhea, classical swine fever and border disease. Antiviral Res 2013; 100:133-50. [DOI: 10.1016/j.antiviral.2013.07.015] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Revised: 07/01/2013] [Accepted: 07/27/2013] [Indexed: 01/13/2023]
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