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Yi W, Wang H, Qin H, Wang Q, Guo R, Wen G, Pan Z. Construction and efficacy of a new live chimeric C-strain vaccine with DIVA characteristics against classical swine fever. Vaccine 2023; 41:2003-2012. [PMID: 36803898 DOI: 10.1016/j.vaccine.2023.02.044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 02/10/2023] [Accepted: 02/13/2023] [Indexed: 02/21/2023]
Abstract
To develop the new classical swine fever (CSF) vaccine candidate with differentiating infected vaccinated animals (DIVA) characteristics, a chimeric CSF virus (CSFV) was constructed based on an infectious cDNA clone of the CSF vaccine C-strain. The 5'- and 3'-untranslated regions (UTRs) and partial E2 region (residues 690-860) of the C-strain were substituted with the corresponding regions of bovine viral diarrhoea virus (BVDV) to construct the chimeric cDNA clone pC/bUTRs-tE2. The chimeric virus rC/bUTRs-tE2 was generated by several passages of pC/bUTRs-tE2-transfected PK15 cells. Stable growth and genetic properties of rC/bUTRs-tE2 were obtained after 30 serial passages. Compared to parental rC/bUTRs-tE2 (1st passage), two residue mutations (M834K and M979K) located in E2 in rC/bUTRs-tE2 P30 were observed. Compared to the C-strain, rC/bUTRs-tE2 exhibited unchanged cell tropism and decreased plaque-forming ability. Substituting the C-strain UTRs with the BVDV UTRs resulted in significantly increased viral replication in PK15 cells. Compared to CSFV Erns-positive and BVDV tE2-negative antibody responses induced by the CSF vaccine C-strain, immunization of rabbits and piglets with rC/bUTRs-tE2 resulted in serological profiles of CSFV Erns- and BVDV tE2-positive antibodies, which are used to serologically discriminate pigs that are clinically infected and vaccinated. Vaccination of piglets with rC/bUTRs-tE2 conferred complete protection against lethal CSFV challenge. Our results suggest that rC/bUTRs-tE2 is a promising new CSF marker vaccine candidate.
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Affiliation(s)
- Weicheng Yi
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Hao Wang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Huan Qin
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China; Laboratory, Wuhan Children's Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430015, China
| | - Qin Wang
- World Organisation for Animal Health Reference Laboratory for Classical Swine Fever, China Institute of Veterinary Drug Control, Beijing 100081, China
| | - Rui Guo
- Key Laboratory of Prevention and Control Agents for Animal Bacteriosis (Ministry of Agriculture and Rural Affairs), Hubei Provincial Key Laboratory of Animal Pathogenic Microbiology, Institute of Animal Husbandry and Veterinary, Hubei Academy of Agricultural Sciences, Wuhan 430064, China
| | - Guoyuan Wen
- Key Laboratory of Prevention and Control Agents for Animal Bacteriosis (Ministry of Agriculture and Rural Affairs), Hubei Provincial Key Laboratory of Animal Pathogenic Microbiology, Institute of Animal Husbandry and Veterinary, Hubei Academy of Agricultural Sciences, Wuhan 430064, China
| | - Zishu Pan
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
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Jang G, Kim J, Park C, Song K, Kang W, Yang K, Lee C. Pathogenicity of a novel classical swine fever LOM vaccine‐derived virus isolated on Jeju Island, South Korea. Vet Med Sci 2022; 8:2434-2443. [DOI: 10.1002/vms3.903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Guehwan Jang
- College of Veterinary Medicine and Virus Vaccine Research Center Gyeongsang National University Jinju Republic of Korea
| | - Joo‐Ah Kim
- Livestock Affairs Division Jeju Special Self‐Governing Province Jeju Republic of Korea
| | - Changnam Park
- Veterinary Research Institute Jeju Special Self‐Governing Province Jeju Republic of Korea
| | - Kyungok Song
- Veterinary Research Institute Jeju Special Self‐Governing Province Jeju Republic of Korea
| | - Won‐Myoung Kang
- Veterinary Research Institute Jeju Special Self‐Governing Province Jeju Republic of Korea
| | - Kyungsu Yang
- Farm & Pharm Veterinary Hospital Jeju Republic of Korea
| | - Changhee Lee
- College of Veterinary Medicine and Virus Vaccine Research Center Gyeongsang National University Jinju Republic of Korea
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Genetic diversity and molecular characterization of classical swine fever virus envelope protein genes E2 and E rns circulating in Vietnam from 2017 to 2019. INFECTION GENETICS AND EVOLUTION 2021; 96:105140. [PMID: 34781037 DOI: 10.1016/j.meegid.2021.105140] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Revised: 11/01/2021] [Accepted: 11/09/2021] [Indexed: 11/22/2022]
Abstract
Classical swine fever virus (CSFV) is an RNA virus that incurs severe economic costs to swine industries worldwide. This study was conducted to investigate the genetic diversity among CSFV strains circulating in Vietnam, with a focus on their genetic variants relative to four vaccine strains. Samples from clinical cases were collected from different provinces of Central and Southern Vietnam from 2017 to 2019. 21 CSFV-positive samples were selected for amplification and sequencing of the full-length Erns and E2 genes. Phylogenetic analyses of these two genes showed that most CSFV strains circulating in Central and Southern Vietnam from 2017 to 2019 belong to subgroup 2.1c, whereas the remaining strains cluster into subgroup 2.2. All CSFV field strains in this study were genetically distant from group 1 strains. Analysis of the E2 and Erns genes indicated that all CSFV field strains have low sequence identity with the vaccine strains (80-83.5% and 82.3-86% sequence identity for E2 and Erns, respectively). Likewise, amino acid-level sequence analysis showed 87.3-91.1% and 87.6-91.6% sequence identity for E2 and Erns, respectively. Together, our findings indicate that CSFV strains circulating in Vietnam belong to subtypes 2.2 and 2.1c, and we also provide novel insights into the epidemiology, molecular characteristics, genetic diversity, and evolution of these circulating CSFV strains.
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Proline to Threonine Mutation at Position 162 of NS5B of Classical Swine Fever Virus Vaccine C Strain Promoted Genome Replication and Infectious Virus Production by Facilitating Initiation of RNA Synthesis. Viruses 2021; 13:v13081523. [PMID: 34452387 PMCID: PMC8402891 DOI: 10.3390/v13081523] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 07/29/2021] [Accepted: 07/30/2021] [Indexed: 12/11/2022] Open
Abstract
The 3′untranslated region (3′UTR) and NS5B of classical swine fever virus (CSFV) play vital roles in viral genome replication. In this study, two chimeric viruses, vC/SM3′UTR and vC/b3′UTR, with 3′UTR substitution of CSFV Shimen strain or bovine viral diarrhea virus (BVDV) NADL strain, were constructed based on the infectious cDNA clone of CSFV vaccine C strain, respectively. After virus rescue, each recombinant chimeric virus was subjected to continuous passages in PK-15 cells. The representative passaged viruses were characterized and sequenced. Serial passages resulted in generation of mutations and the passaged viruses exhibited significantly increased genomic replication efficiency and infectious virus production compared to parent viruses. A proline to threonine mutation at position 162 of NS5B was identified in both passaged vC/SM3′UTR and vC/b3′UTR. We generated P162T mutants of two chimeras using the reverse genetics system, separately. The single P162T mutation in NS5B of vC/SM3′UTR or vC/b3′UTR played a key role in increased viral genome replication and infectious virus production. The P162T mutation increased vC/SM3′UTRP162T replication in rabbits. From RNA-dependent RNA polymerase (RdRp) assays in vitro, the NS5B containing P162T mutation (NS5BP162T) exhibited enhanced RdRp activity for different RNA templates. We further identified that the enhanced RdRp activity originated from increased initiation efficiency of RNA synthesis. These findings revealed a novel function for the NS5B residue 162 in modulating pestivirus replication.
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Jang G, Kim JA, Yoo H, Yang K, Yang HS, Park C, Jeong K, Park CK, Lyoo YS, Lee C. Genomic characterization of classical swine fever virus LOM variants with 3'-UTR INDELs from pigs on Jeju Island, South Korea. Arch Virol 2020; 165:1691-1696. [PMID: 32394293 DOI: 10.1007/s00705-020-04651-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 04/10/2020] [Indexed: 12/19/2022]
Abstract
Classical swine fever virus (CSFV) reemerged in naïve pig herds on Jeju Island, South Korea, due to the accidental introduction of the LOM vaccine strain in 2014. Since this reemergence, the previously CSFV-free region has experienced numerous outbreaks, causing the virus to become endemic in provincial herds. In this study, we determined the complete genome sequences and investigated the molecular characteristics of LOM-derived field CSFV strains with unique insertion-deletion (INDEL) mutations in the 3'-untranslated region (UTR) that were responsible for ongoing sporadic outbreaks on Jeju Island in 2019. The Jeju LOM-derived variants that emerged in 2019 had their own INDEL signatures in the 3'-UTR, resulting in changes to the predicted secondary stem-loop structures. The genomes of these strains were 12,297-12,302 nucleotides in length, one nucleotide (nt) shorter or one, two, or four nt longer than the reference LOM strain. The 3'-UTR INDEL variants shared 98.8-99.0% and 98.3-98.6% identity with the LOM strain at the polyprotein and full-genome level, respectively. The total number of genetic variations between the LOM vaccine strain and the 3'-UTR INDEL isolates ranged from 161 to 202 and 37 to 45 at the nucleotide and amino acid level, respectively. These mutations were broadly dispersed throughout the genome and particularly clustered in NS2 and the 3'-UTR, possibly triggering a reversion to low virulence and allowing the virus to adapt to improve its persistence in the field. This study provides important information about the genetic evolution of LOM-derived CSFV circulating in the free region, and suggests that it arose from continuous non-lethal mutations to ensure viral fitness in host animals.
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Affiliation(s)
- Guehwan Jang
- Animal Virology Laboratory, BK21 Plus KNU Creative BioResearch Group, School of Life Sciences, College of Natural Sciences, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Joo-Ah Kim
- Animal Health Division, Jeju Special Self-Governing Province, Jeju, 63122, South Korea
| | - Hyekyung Yoo
- Farm and Pharm Veterinary Hospital, Jeju, 63029, Republic of Korea
| | - Kyungsu Yang
- Farm and Pharm Veterinary Hospital, Jeju, 63029, Republic of Korea
| | - Hyoung-Seok Yang
- Veterinary Research Institute, Jeju Special Self-Governing Province, Jeju, 63344, South Korea
| | - Changnam Park
- Veterinary Research Institute, Jeju Special Self-Governing Province, Jeju, 63344, South Korea
| | - Kyongju Jeong
- Veterinary Research Institute, Jeju Special Self-Governing Province, Jeju, 63344, South Korea
| | - Choi-Kyu Park
- College of Veterinary Medicine, Kyungpook National University, Daegu, 41566, South Korea
| | - Young S Lyoo
- College of Veterinary Medicine, Konkuk University, Seoul, 05029, South Korea
| | - Changhee Lee
- Animal Virology Laboratory, BK21 Plus KNU Creative BioResearch Group, School of Life Sciences, College of Natural Sciences, Kyungpook National University, Daegu, 41566, Republic of Korea.
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A Polyuridine Insertion in the 3' Untranslated Region of Classical Swine Fever Virus Activates Immunity and Reduces Viral Virulence in Piglets. J Virol 2020; 94:JVI.01214-19. [PMID: 31645448 PMCID: PMC6955259 DOI: 10.1128/jvi.01214-19] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Accepted: 10/11/2019] [Indexed: 01/15/2023] Open
Abstract
Classical swine fever (CSF), a highly contagious viral disease of pigs, is still endemic in some countries of Asia and Central and South America. Considering that the 3′ untranslated region (3′ UTR) plays an important role in flavivirus replication, the present study showed for the first time that a long polyuridine sequence acquired in the 3′ UTR by an endemic CSFV isolate can activate immunity, control viral replication, and modulate disease in piglets. Our findings provide new avenues for the development of novel vaccines against infections with CSF virus and other flaviviruses. Knowledge of molecular virulence determinants is also relevant for future development of rapid and efficient diagnostic tools for the prediction of the virulence of field isolates and for efficient CSF control. Low-virulence classical swine fever virus (CSFV) strains make CSF eradication particularly difficult. Few data are available on the molecular determinants of CSFV virulence. The aim of the present study was to assess a possible role for CSFV virulence of a unique, uninterrupted 36-uridine (poly-U) sequence found in the 3′ untranslated region (3′ UTR) of the low-virulence CSFV isolate Pinar de Rio (PdR). To this end, a pair of cDNA-derived viruses based on the PdR backbone were generated, one carrying the long poly-U insertion in the 3′ UTR (vPdR-36U) and the other harboring the standard 5 uridines at this position (vPdR-5U). Two groups of 20 5-day-old piglets were infected with vPdR-36U and vPdR-5U. Ten contact piglets were added to each group. Disease progression, virus replication, and immune responses were monitored for 5 weeks. The vPdR-5U virus was significantly more virulent than the vPdR-36U virus, with more severe disease, higher mortality, and significantly higher viral loads in serum and body secretions, despite similar replication characteristics in cell culture. The two viruses were transmitted to all contact piglets. Ninety percent of the piglets infected with vPdR-36U seroconverted, while only one vPdR-5U-infected piglet developed antibodies. The vPdR-5U-infected piglets showed only transient alpha interferon (IFN-α) responses in serum after 1 week of infection, while the vPdR-36U-infected piglets showed sustained IFN-α levels during the first 2 weeks. Taken together, these data show that the 3′ UTR poly-U insertion acquired by the PdR isolate reduces viral virulence and activates the innate and humoral immune responses without affecting viral transmission. IMPORTANCE Classical swine fever (CSF), a highly contagious viral disease of pigs, is still endemic in some countries of Asia and Central and South America. Considering that the 3′ untranslated region (3′ UTR) plays an important role in flavivirus replication, the present study showed for the first time that a long polyuridine sequence acquired in the 3′ UTR by an endemic CSFV isolate can activate immunity, control viral replication, and modulate disease in piglets. Our findings provide new avenues for the development of novel vaccines against infections with CSF virus and other flaviviruses. Knowledge of molecular virulence determinants is also relevant for future development of rapid and efficient diagnostic tools for the prediction of the virulence of field isolates and for efficient CSF control.
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E2 and Erns of classical swine fever virus C-strain play central roles in its adaptation to rabbits. Virus Genes 2019; 55:238-242. [DOI: 10.1007/s11262-018-01631-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 12/27/2018] [Indexed: 01/30/2023]
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Zhang H, Leng C, Tian Z, Liu C, Chen J, Bai Y, Li Z, Xiang L, Zhai H, Wang Q, Peng J, An T, Kan Y, Yao L, Yang X, Cai X, Tong G. Complete genomic characteristics and pathogenic analysis of the newly emerged classical swine fever virus in China. BMC Vet Res 2018; 14:204. [PMID: 29940930 PMCID: PMC6019732 DOI: 10.1186/s12917-018-1504-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 05/29/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Classical swine fever (CSF) is one of the most devastating and highly contagious viral diseases in the world. Since late 2014, outbreaks of a new sub-genotype 2.1d CSF virus (CSFV) had caused substantial economic losses in numbers of C-strain vaccinated swine farms in China. The objective of the present study was to explore the genomic characteristics and pathogenicity of the newly emerged CSFV isolates in China during 2014-2015. RESULTS All the new 8 CSFV isolates belonged to genetic sub-genotype 2.1d. Some genomic variations or deletions were found in the UTRs and E2 of these new isolates. In addition, the pathogenicity of HLJ1 was less than Shimen, suggesting the HLJ1 of sub-genotype 2.1d may be a moderated pathogenic isolate and the C-strain vaccine can supply complete protection. CONCLUSIONS The new CSFV isolates with unique genomic characteristics and moderate pathogenicity can be epidemic in many large-scale C-strain vaccinated swine farms. This study provides the information should be merited special attention on establishing prevention and control policies for CSF.
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Affiliation(s)
- Hongliang Zhang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150001 China
| | - Chaoliang Leng
- Henan Key Laboratory of Insect Biology in Funiu Mountain, Henan Provincial Engineering Laboratory of Insects Bio-reactor, China-UK-NYNU-RRes Joint Laboratory of Insect Biology, Nanyang Normal University, Nanyang, 473061 China
| | - Zhijun Tian
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150001 China
| | - Chunxiao Liu
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150001 China
| | - Jiazeng Chen
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150001 China
| | - Yun Bai
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150001 China
| | - Zhen Li
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150001 China
| | - Lirun Xiang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150001 China
| | - Hongyue Zhai
- Henan Key Laboratory of Insect Biology in Funiu Mountain, Henan Provincial Engineering Laboratory of Insects Bio-reactor, China-UK-NYNU-RRes Joint Laboratory of Insect Biology, Nanyang Normal University, Nanyang, 473061 China
| | - Qian Wang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150001 China
| | - Jinmei Peng
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150001 China
| | - Tongqing An
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150001 China
| | - Yunchao Kan
- Henan Key Laboratory of Insect Biology in Funiu Mountain, Henan Provincial Engineering Laboratory of Insects Bio-reactor, China-UK-NYNU-RRes Joint Laboratory of Insect Biology, Nanyang Normal University, Nanyang, 473061 China
| | - Lunguang Yao
- Henan Key Laboratory of Insect Biology in Funiu Mountain, Henan Provincial Engineering Laboratory of Insects Bio-reactor, China-UK-NYNU-RRes Joint Laboratory of Insect Biology, Nanyang Normal University, Nanyang, 473061 China
| | - Xufu Yang
- North Guangdong Collaborative Innovation and Development Center of Pig Farming and Disease Control, Shaoguan University, Shaoguan, 512005 China
| | - Xuehui Cai
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150001 China
| | - Guangzhi Tong
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, No. 518, Ziyue Road, Minhang District, Shanghai, 200241 China
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Li HM, Zhao ZY, Guo KK, Jiang YF, Zhang WM, Zhang YM, Liu W, Wang JY. Differentiation of virulent Shimen and vaccine C strains of classical swine fever virus by duplex reverse-transcription polymerase chain reaction. BIOTECHNOL BIOTEC EQ 2017. [DOI: 10.1080/13102818.2017.1355263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Affiliation(s)
- Hai-min Li
- Department of Prevention, College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, P.R. China
| | - Zi-yin Zhao
- Department of Prevention, College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, P.R. China
| | - Kang-kang Guo
- Department of Prevention, College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, P.R. China
| | - Yan-fen Jiang
- Department of Prevention, College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, P.R. China
| | - Wei-min Zhang
- Department of Prevention, College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, P.R. China
| | - Yan-ming Zhang
- Department of Prevention, College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, P.R. China
| | - Wei Liu
- Department of Prevention, College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, P.R. China
| | - Jing-yu Wang
- Department of Prevention, College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, P.R. China
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Coronado L, Liniger M, Muñoz-González S, Postel A, Pérez LJ, Pérez-Simó M, Perera CL, Frías-Lepoureau MT, Rosell R, Grundhoff A, Indenbirken D, Alawi M, Fischer N, Becher P, Ruggli N, Ganges L. Novel poly-uridine insertion in the 3'UTR and E2 amino acid substitutions in a low virulent classical swine fever virus. Vet Microbiol 2017; 201:103-112. [PMID: 28284595 DOI: 10.1016/j.vetmic.2017.01.013] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 01/10/2017] [Accepted: 01/12/2017] [Indexed: 12/24/2022]
Abstract
In this study, we compared the virulence in weaner pigs of the Pinar del Rio isolate and the virulent Margarita strain. The latter caused the Cuban classical swine fever (CSF) outbreak of 1993. Our results showed that the Pinar del Rio virus isolated during an endemic phase is clearly of low virulence. We analysed the complete nucleotide sequence of the Pinar del Rio virus isolated after persistence in newborn piglets, as well as the genome sequence of the inoculum. The consensus genome sequence of the Pinar del Rio virus remained completely unchanged after 28days of persistent infection in swine. More importantly, a unique poly-uridine tract was discovered in the 3'UTR of the Pinar del Rio virus, which was not found in the Margarita virus or any other known CSFV sequences. Based on RNA secondary structure prediction, the poly-uridine tract results in a long single-stranded intervening sequence (SS) between the stem-loops I and II of the 3'UTR, without major changes in the stem- loop structures when compared to the Margarita virus. The possible implications of this novel insertion on persistence and attenuation remain to be investigated. In addition, comparison of the amino acid sequence of the viral proteins Erns, E1, E2 and p7 of the Margarita and Pinar del Rio viruses showed that all non-conservative amino acid substitutions acquired by the Pinar del Rio isolate clustered in E2, with two of them being located within the B/C domain. Immunisation and cross-neutralisation experiments in pigs and rabbits suggest differences between these two viruses, which may be attributable to the amino acid differences observed in E2. Altogether, these data provide fresh insights into viral molecular features which might be associated with the attenuation and adaptation of CSFV for persistence in the field.
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Affiliation(s)
- Liani Coronado
- Centro Nacional de Sanidad Agropecuaria (CENSA), La Habana, Cuba; IRTA, Centre de Recerca en Sanitat Animal (CReSA, IRTA-UAB), Campus de la Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain
| | - Matthias Liniger
- Institute of Virology and Immunology IVI, Mittelhäusern, Switzerland
| | - Sara Muñoz-González
- IRTA, Centre de Recerca en Sanitat Animal (CReSA, IRTA-UAB), Campus de la Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain
| | - Alexander Postel
- EU and OIE Reference Laboratory for Classical Swine Fever, Institute of Virology, Department of Infectious Diseases, University of Veterinary Medicine, Hannover, Germany
| | | | - Marta Pérez-Simó
- IRTA, Centre de Recerca en Sanitat Animal (CReSA, IRTA-UAB), Campus de la Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain
| | | | | | - Rosa Rosell
- IRTA, Centre de Recerca en Sanitat Animal (CReSA, IRTA-UAB), Campus de la Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain; Departamentd'Agricultura, Ramaderia, Pesca, Alimentació i Medi Natural, (DAAM), Generalitat de Catalunya, Spain
| | - Adam Grundhoff
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Research Group Virus Genomics, Hamburg, Germany
| | - Daniela Indenbirken
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Research Group Virus Genomics, Hamburg, Germany
| | - Malik Alawi
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Research Group Virus Genomics, Hamburg, Germany; Bioinformatics Service Facility, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Nicole Fischer
- Institute for Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Paul Becher
- EU and OIE Reference Laboratory for Classical Swine Fever, Institute of Virology, Department of Infectious Diseases, University of Veterinary Medicine, Hannover, Germany
| | - Nicolas Ruggli
- Institute of Virology and Immunology IVI, Mittelhäusern, Switzerland
| | - Llilianne Ganges
- IRTA, Centre de Recerca en Sanitat Animal (CReSA, IRTA-UAB), Campus de la Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain.
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Fan YH, Lin YL, Hwang YC, Yang HC, Chiu HC, Chiou SH, Jong MH, Chow KC, Lin CC. T-cell factor-4 and MHC upregulation in pigs receiving a live attenuated classical swine fever virus (CSFV) vaccine strain with interferon-gamma adjuvant. Vet J 2016; 216:148-56. [PMID: 27687943 DOI: 10.1016/j.tvjl.2016.07.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2014] [Revised: 07/13/2016] [Accepted: 07/15/2016] [Indexed: 01/15/2023]
Abstract
The effect of co-administration of interferon (IFN)-γ in pigs undergoing vaccination with an attenuated strain (LPC) of classical swine fever virus (CSFV) was investigated. Unvaccinated pigs demonstrated pyrexia and died 7-9 days after challenge with virulent CSFV. Pigs receiving the attenuated vaccine remained healthy after virus challenge, except for mild, transient pyrexia, whereas pigs receiving IFN-γ simultaneously with the vaccine demonstrated normal body temperatures after virus challenge. Examination by nested RT-PCR revealed greater viral load in the spleens of the pigs vaccinated with the attenuated CSFV, compared with those that had additionally received IFN-γ. Expression of major histocompatibility complex (MHC) class I and MHC class II molecules was upregulated in the spleens of the IFN-γ treated vaccinated pigs, demonstrated by immunohistochemistry. Based on Western blot analysis, anti-CSFV IgG2 antibodies were elevated in vaccinated pigs by co-administration of IFN-γ (IFN-γ(Hi): P < 0.01; IFN-γ(Lo): P <0.05). By employing the suppression subtractive hybridization technique, RT-PCR, in situ hybridization, and immunohistochemistry, T-cell factor-4 (Tcf-4) mRNA and protein expression were found to be upregulated in the spleens of vaccinated pigs that had received IFN-γ. This study suggests involvement of Tcf-4 in IFN-γ-mediated immune regulation following CSFV vaccination.
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Affiliation(s)
- Y-H Fan
- Graduate Institute of Microbiology and Public Health, National Chung Hsing University, Taichung 40227, Taiwan, Republic of China
| | - Y-L Lin
- Epidemiology Research Division, Animal Health Research Institute, Council of Agriculture, Executive Yuan, Tamsui, New Taipei City 251, Taiwan, Republic of China
| | - Y-C Hwang
- Graduate Institute of Microbiology and Public Health, National Chung Hsing University, Taichung 40227, Taiwan, Republic of China
| | - H-C Yang
- Graduate Institute of Microbiology and Public Health, National Chung Hsing University, Taichung 40227, Taiwan, Republic of China
| | - H-C Chiu
- Graduate Institute of Microbiology and Public Health, National Chung Hsing University, Taichung 40227, Taiwan, Republic of China
| | - S-H Chiou
- Graduate Institute of Microbiology and Public Health, National Chung Hsing University, Taichung 40227, Taiwan, Republic of China.
| | - M-H Jong
- Hog Cholera Division, Animal Health Research Institute, Council of Agriculture, Executive Yuan, Tamsui, New Taipei City 251, Taiwan, Republic of China
| | - K-C Chow
- Institute of Biomedical Sciences, National Chung Hsing University, Taichung 40227, Taiwan, Republic of China
| | - C-C Lin
- Department of Veterinary Medicine, National Chung Hsing University, Taichung 40227, Taiwan, Republic of China
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Zhou W, Gao S, Podgórska K, Stadejek T, Qiu HJ, Yin H, Drew T, Liu L. Rovac is the possible ancestor of the Russian lapinized vaccines LK-VNIVViM and CS strains but not the Chinese strain (C-strain) vaccine against classical swine fever. Vaccine 2015; 32:6639-42. [PMID: 25306909 DOI: 10.1016/j.vaccine.2014.09.058] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Revised: 09/19/2014] [Accepted: 09/24/2014] [Indexed: 11/28/2022]
Abstract
Classical swine fever (CSF), or hog cholera, is a highly contagious disease that emerged in the first half of the nineteenth century. To fight against the disease and protect pigs, different vaccines were developed, including early generation of lapinized Rovac strain and the later development of the “Chinese” strain (C-strain). However, details of the development of these vaccines are lost in history. In order to investigate the phylogenetic relationship between the Rovac and other lapinized vaccines, this study determined the genome sequence of the Rovac, which comprised 12,304 nucleotides, notably with the 3′untranslated region (3′UTR) containing a 13-nucleotide insertion. The near-complete genome of Russian vaccine strain LK-VNIVViM was determined by next-generation sequencing on Illumina MiSeq platform. Whole genome phylogenetic analysis revealed a closer relationship of the Rovac strain with the Russian LK-VNIVViM, CS strain and its derivative RUCSFPLUM (genotype 1.2), rather than with the C-strain (genotype 1.1). In addition, it demonstrated an ancestry role of the LK-VNIVViM in relation to the CS strain and RUCSFPLUM. The study suggested that the Rovac vaccine is the possible ancestor of the Russian vaccine strains but not the C-strain vaccine.
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Affiliation(s)
- Weiguang Zhou
- Department of Virology, Immunobiology and Parasitology, National Veterinary Institute, Uppsala, Sweden
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13
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Genome sequence of classical Swine Fever virus genotype 1.1 with a genetic marker of attenuation detected in a continuous porcine cell line. GENOME ANNOUNCEMENTS 2015; 3:3/2/e00375-15. [PMID: 25931601 PMCID: PMC4417697 DOI: 10.1128/genomea.00375-15] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The complete genome sequencing and analysis of a classical swine fever virus (CSFV) detected in a porcine kidney cell line revealed a close relationship with genotype 1.1 viruses circulating in India and China. The presence of consecutive T insertions in the 3′ untranslated region (UTR), as seen in vaccine strains of CSFV, suggested some degree of attenuation.
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14
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15
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Jiang DL, Gong WJ, Li RC, Liu GH, Hu YF, Ge M, Wang SQ, Yu XL, Tu C. Phylogenetic analysis using E2 gene of classical swine fever virus reveals a new subgenotype in China. INFECTION GENETICS AND EVOLUTION 2013; 17:231-8. [DOI: 10.1016/j.meegid.2013.04.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2012] [Revised: 03/21/2013] [Accepted: 04/03/2013] [Indexed: 10/26/2022]
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16
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Leifer I, Hoeper D, Blome S, Beer M, Ruggli N. Clustering of classical swine fever virus isolates by codon pair bias. BMC Res Notes 2011; 4:521. [PMID: 22126254 PMCID: PMC3341591 DOI: 10.1186/1756-0500-4-521] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2011] [Accepted: 11/29/2011] [Indexed: 11/29/2022] Open
Abstract
Background The genetic code consists of non-random usage of synonymous codons for the same amino acids, termed codon bias or codon usage. Codon juxtaposition is also non-random, referred to as codon context bias or codon pair bias. The codon and codon pair bias vary among different organisms, as well as with viruses. Reasons for these differences are not completely understood. For classical swine fever virus (CSFV), it was suggested that the synonymous codon usage does not significantly influence virulence, but the relationship between variations in codon pair usage and CSFV virulence is unknown. Virulence can be related to the fitness of a virus: Differences in codon pair usage influence genome translation efficiency, which may in turn relate to the fitness of a virus. Accordingly, the potential of the codon pair bias for clustering CSFV isolates into classes of different virulence was investigated. Results The complete genomic sequences encoding the viral polyprotein of 52 different CSFV isolates were analyzed. This included 49 sequences from the GenBank database (NCBI) and three newly sequenced genomes. The codon usage did not differ among isolates of different virulence or genotype. In contrast, a clustering of isolates based on their codon pair bias was observed, clearly discriminating highly virulent isolates and vaccine strains on one side from moderately virulent strains on the other side. However, phylogenetic trees based on the codon pair bias and on the primary nucleotide sequence resulted in a very similar genotype distribution. Conclusion Clustering of CSFV genomes based on their codon pair bias correlate with the genotype rather than with the virulence of the isolates.
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Affiliation(s)
- Immanuel Leifer
- Institute of Virology and Immunoprophylaxis (IVI), Sensemattstrasse 293, CH-3147 Mittelhäusern, Switzerland.
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17
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Gupta PK, Saini M, Dahiya SS, Patel CL, Sonwane AA, Rai DV, Pandey KD. Molecular characterization of lapinized classical Swine Fever vaccine strain by full-length genome sequencing and analysis. Anim Biotechnol 2011; 22:111-7. [PMID: 21500112 DOI: 10.1080/10495398.2011.566472] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The complete genome of a lapinized classical swine fever virus (CSFV) vaccine strain was amplified into nine overlapping fragments by RT-PCR, and nucleotide sequences were determined. Complete genome sequence alignment and phylogenetic analysis indicated 92.6-98.6% identities at the nucleotide level with other reported CSFV strains and could be grouped into subgroup 1.1 along with other attenuated strains of CSFV. The 5'-UTR demonstrated >97.0% nucleotide similarity with most of vaccine CSFV strains from China. Further, its 3'-UTR sequence indicated a length similar to all the CSFV strains from China with >98.0% nucleotide similarity, although high length heterogeneity of 3'-UTR was reported among different CSFV strains. There was 12 nt (TTTTCTTTTTTT) insertion in 3'-UTR similar to other reported attenuated vaccine strains. However, secondary structure of 3'-UTR indicated that Indian CSFV strain requires further passage to obtain a 3'-UTR structure similar to most of the attenuated strains.
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Affiliation(s)
- Praveen K Gupta
- Division of Animal Biotechnology, Indian Veterinary Research Institute, Izatnagar, India.
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18
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Lack of phylogenetic evidence that the Shimen strain is the parental strain of the lapinized Chinese strain (C-strain) vaccine against classical swine fever. Arch Virol 2011; 156:1041-4. [DOI: 10.1007/s00705-011-0948-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2010] [Accepted: 02/04/2011] [Indexed: 11/26/2022]
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19
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Uttenthal A, Parida S, Rasmussen TB, Paton DJ, Haas B, Dundon WG. Strategies for differentiating infection in vaccinated animals (DIVA) for foot-and-mouth disease, classical swine fever and avian influenza. Expert Rev Vaccines 2010; 9:73-87. [PMID: 20021307 DOI: 10.1586/erv.09.130] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The prophylactic use of vaccines against exotic viral infections in production animals is undertaken exclusively in regions where the disease concerned is endemic. In such areas, the infection pressure is very high and so, to assure optimal protection, the most efficient vaccines are used. However, in areas considered to be free from these diseases and in which there is the possibility of only limited outbreaks, the use of Differentiation of Infected from Vaccinated Animals (DIVA) or marker vaccines allows for vaccination while still retaining the possibility of serological surveillance for the presence of infection. This literature review describes the current knowledge on the use of DIVA diagnostic strategies for three important transboundary animal diseases: foot-and-mouth disease in cloven-hoofed animals, classical swine fever in pigs and avian influenza in poultry.
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Affiliation(s)
- Ase Uttenthal
- National Veterinary Institute, Technical University of Denmark, Lindholm, DK-4771 Kalvehave, Denmark.
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20
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Analysis of synonymous codon usage in classical swine fever virus. Virus Genes 2008; 38:104-12. [PMID: 18958611 PMCID: PMC7089228 DOI: 10.1007/s11262-008-0296-z] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2008] [Accepted: 10/09/2008] [Indexed: 01/27/2023]
Abstract
Using the complete genome sequences of 35 classical swine fever viruses (CSFV) representing all three genotypes and all three kinds of virulence, we analyzed synonymous codon usage and the relative dinucleotide abundance in CSFV. The general correlation between base composition and codon usage bias suggests that mutational pressure rather than natural selection is the main factor that determines the codon usage bias in CSFV. Furthermore, we observed that the relative abundance of dinucleotides in CSFV is independent of the overall base composition but is still the result of differential mutational pressure, which also shapes codon usage. In addition, other factors, such as the subgenotypes and aromaticity, also influence the codon usage variation among the genomes of CSFV. This study represents the most comprehensive analysis to date of CSFV codon usage patterns and provides a basic understanding of the mechanisms for codon usage bias.
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21
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Pan CH, Jong MH, Huang YL, Huang TS, Chao PH, Lai SS. Rapid detection and differentiation of wild-type and three attenuated lapinized vaccine strains of classical swine fever virus by reverse transcription polymerase chain reaction. J Vet Diagn Invest 2008; 20:448-56. [PMID: 18599849 DOI: 10.1177/104063870802000406] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
A simple one-step reverse transcription polymerase chain reaction (RT-PCR) method was developed based on T-rich insertions in the viral genome for simultaneous detection and differentiation of wild type and vaccine strains of Classical swine fever virus (CSFV). The CSFV-specific primers were designed to contain the sequences of the T-rich insertion sites that exist uniquely in the 3' nontranslated regions (3' NTR) of the genome of lapinized CSFV vaccine strains. By using a one-step RT-PCR or a nested PCR followed by an agarose gel electrophoresis or a multicapillary electrophoresis, the wild-type and lapinized vaccine strains of CSFV in clinical samples could be detected and accurately distinguished. These assays can be applied to at least 3 attenuated lapinized vaccine strains, lapinized Philippines Coronel (LPC), hog cholera lapinized virus (HCLV), and Chinese strain (C strain). The detection limit of the wild-type virus was 6.3 TCID(50) (50% tissue culture infective dose)/ml for RT-PCR and 0.63 TCID(50)/ml for nested PCR. In previous studies, notable T-rich insertions of 12-13 nucleotides (nt) were found in the 3' NTR of the genome of lapinized vaccine strains of CSFV. However, this study discovered that 2 T-rich insertions, 42 and 36 nt in length, are present in the viral genome of lapinized vaccine strains LPC/PRK (primary rabbit kidney) and LPC/TS (Tam-Sui), respectively. These T-rich insertions of 12, 36, and 42 nt length increases the size of PCR fragments, which are favorable genetic markers for rapid detection of and differentiation between wild-type and different lapinized vaccine strains of CSFV.
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Affiliation(s)
- Chu-Hsiang Pan
- Division of Hog Cholera Research, Animal Health Rsearch Institute, Council of Agriculture, Tamsui, Taipei, Taiwan
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22
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Complete genome sequence of attenuated low-temperature Thiverval strain of classical swine fever virus. Virus Genes 2008; 36:531-8. [DOI: 10.1007/s11262-008-0229-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2007] [Accepted: 03/31/2008] [Indexed: 12/29/2022]
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23
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Sheng C, Xiao M, Geng X, Liu J, Wang Y, Gu F. Characterization of interaction of classical swine fever virus NS3 helicase with 3' untranslated region. Virus Res 2007; 129:43-53. [PMID: 17566586 DOI: 10.1016/j.virusres.2007.05.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2007] [Revised: 05/03/2007] [Accepted: 05/04/2007] [Indexed: 11/24/2022]
Abstract
The classical swine fever virus (CSFV) full-length NS3 protein (NS3F) and the truncated NS3 protein (NS3H) with postulated helicase domain were expressed and demonstrated to have helicase activity. Further, the electrophoretic mobility shift assays containing NS3H and the viral 3' terminal sequences showed that NS3H specifically bound to the plus- and minus-strand 3'UTR. The minus-strand 3'UTR had higher binding activity. The 21-nt fragments at the 3'-most terminal sequences of both 3'UTRs were essential to NS3H binding. A 12-nt insertion, CUUUUUUCUUUU, present in the 3'UTR of a CSFV live attenuated vaccine strain, was also found to be deleterious to helicase binding. Intact secondary structure of 3' terminal sequence of 3'UTR might be important in helicase binding. Our results show that interaction between the helicase and the viral 3'UTR is similar to that between the replicase and the 3'UTR, suggesting that NS3 helicase is important for CSFV genomic replication.
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Affiliation(s)
- Chun Sheng
- College of Life and Environment Sciences, Shanghai Normal University, Shanghai 200234, China
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24
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QIU HJ, SHEN RX, TONG GZ. The Lapinized Chinese Strain Vaccine Against Classical Swine Fever Virus: A Retrospective Review Spanning Half A Century. ACTA ACUST UNITED AC 2006. [DOI: 10.1016/s1671-2927(06)60013-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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25
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Xiao M, Gao J, Wang W, Wang Y, Chen J, Chen J, Li B. Specific interaction between the classical swine fever virus NS5B protein and the viral genome. ACTA ACUST UNITED AC 2004; 271:3888-96. [PMID: 15373834 DOI: 10.1111/j.1432-1033.2004.04325.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The NS5B protein of the classical swine fever virus (CSFV) is the RNA-dependent RNA polymerase of the virus and is able to catalyze the viral genome replication. The 3' untranslated region is most likely involved in regulation of the Pestivirus genome replication. However, little is known about the interaction between the CSFV NS5B protein and the viral genome. We used different RNA templates derived from the plus-strand viral genome, or the minus-strand viral genome and the CSFV NS5B protein obtained from the Escherichia coli expression system to address this problem. We first showed that the viral NS5B protein formed a complex with the plus-strand genome through the genomic 3' UTR and that the NS5B protein was also able to bind the minus-strand 3' UTR. Moreover, it was found that viral NS5B protein bound the minus-strand 3' UTR more efficiently than the plus-strand 3' UTR. Further, we observed that the plus-strand 3' UTR with deletion of CCCGG or 21 continuous nucleotides at its 3' terminal had no binding activity and also lost the activity for initiation of minus-strand RNA synthesis, which similarly occurred in the minus-strand 3' UTR with CATATGCTC or the 21 nucleotide fragment deleted from the 3' terminal. Therefore, it is indicated that the 3' CCCGG sequence of the plus-strand 3' UTR, and the 3' CATATGCTC fragment of the minus-strand are essential to in vitro synthesis of the minus-strand RNA and the plus-strand RNA, respectively. The same conclusion is also appropriate for the 3' 21 nucleotide terminal site of both the 3' UTRs.
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Affiliation(s)
- Ming Xiao
- Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, The Institute of Biodiversity Science, Fudan University, Shanghai 200433, China
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26
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Xiao M, Gao J, Wang Y, Wang X, Lu W, Zhen Y, Chen J, Li B. Influence of a 12-nt insertion present in the 3' untranslated region of classical swine fever virus HCLV strain genome on RNA synthesis. Virus Res 2004; 102:191-8. [PMID: 15084401 DOI: 10.1016/j.virusres.2004.01.029] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2003] [Revised: 01/10/2004] [Accepted: 01/15/2004] [Indexed: 10/26/2022]
Abstract
The function of a 12-nt insertion 'CTTTTTTCTTTT' in the 3' untranslated region (3'UTR) of the HCLV strain, a vaccine strain derived from the Shimen strain of classical swine fever virus (CSFV), was examined in vitro. RNA synthesis increased when the 12-nt insertion was deleted from the 3'UTR of the HCLV strain. RNA synthesis also decreased when the 12-nt insertion was introduced into the 3'UTR of the CSFV Shimen, virulent strain. Therefore, the 12-nt insertion present in the 3'UTR of the HCLV strain may be a marker for avirulence. It was also found that the predicted secondary structure of the 3'UTR of the HCLV strain was more stable when the 12-nt insertion was deleted, and that the 3'UTR of Shimen strain was more unstable when the 12-nt insertion was introduced. Replacement of the 12-nt insertion 'CTTTTTTCTTTT' by another 12-nt fragment 'ATTATTATTTAT' in the 3'UTR of HCLV strain facilitated RNA synthesis and stabilized the predicted secondary structure, which was also observed in the 3'UTR of the Shimen strain.
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Affiliation(s)
- Ming Xiao
- Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, The Institute of Biodiversity Science, Fudan University, Shanghai, PR China
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27
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Abstract
There are two types of classical swine fever vaccines available: the classical live and the recently developed E2 subunit vaccines. The live Chinese strain vaccine is the most widely used. After a single vaccination, it confers solid immunity within a few days that appears to persist lifelong. The E2 subunit vaccine induces immunity from approximately 10-14 days after a single vaccination. The immunity may persist for more than a year, but is then not complete. The Chinese strain vaccine may establish a strong herd immunity 1-2 weeks earlier than the E2 vaccine. The ability of the Chinese vaccine strain to prevent congenital infection has not been reported, but the E2 subunit vaccine does not induce complete protection against congenital infection. Immunological mechanisms that underlie the protective immunity are still to be elucidated. Both types of vaccine are considered to be safe. A great advantage of the E2 subunit vaccine is that it allows differentiation of infected pigs from vaccinated pigs and is referred to as a DIVA vaccine. However, the companion diagnostic E(rns) ELISA to actually make that differentiation should be improved. Many approaches to develop novel vaccines have been described, but none of these is likely to result in a new DIVA vaccine reaching the market in the next 5-10 years. Countries where classical swine fever is endemic can best control the infection by systematic vaccination campaigns, accompanied by the normal diagnostic procedures and control measures. Oral vaccination of wild boar may contribute to lowering the incidence of classical swine fever, and consequently diminishing the threat of virus introduction into domestic pigs. Free countries should not vaccinate and should be highly alert to rapidly diagnose any new outbreak. Once a new introduction of classical swine fever virus in dense pig areas has been confirmed, an emergency vaccination programme should be immediately instituted, for maximum benefit. The question is whether the time is ripe to seriously consider global eradication of classical swine fever virus.
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Affiliation(s)
- J T van Oirschot
- Virus Discovery Unit, ID-Lelystad, PO Box 65, 8200 AB, Lelystad, The Netherlands.
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Oleksiewicz MB, Rasmussen TB, Normann P, Uttenthal A. Determination of the sequence of the complete open reading frame and the 5'NTR of the Paderborn isolate of classical swine fever virus. Vet Microbiol 2003; 92:311-25. [PMID: 12554101 DOI: 10.1016/s0378-1135(02)00424-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The classical swine fever (CSF) epidemic in the Netherlands in 1997-1998 lasted 14 months, during which 429 infected and 1300 at risk herds were culled, at an estimated economical cost of 2 billion US dollars. Despite the overwhelming scale of the epizootic, the CSF virus (CSFV) strain causing the outbreak has remained largely uncharacterized. The Dutch epizootic is epidemiologically linked to a small CSF outbreak in 1997, in Paderborn in Germany. E2 and partial 5' NTR sequencing has shown that the index Paderborn isolate, and several Dutch isolates taken during the 1997-1998 epizootic, are virtually identical, confirming that the Paderborn isolate triggered the Dutch outbreak, and furthermore showing that this single isolate was stable throughout the whole Dutch outbreak (the above reviewed in [C. Terpstra, A. J. de Smit, Veterinary Microbiol. 77 (2000) 3-15]). We determined the nucleotide sequence of the 5' NTR (by 5' RACE) and the complete open reading frame of the Paderborn isolate (GenBank AY072924). Our sequence was identical to previously published partial 5'NTR and E2 sequences for the index Paderborn 1997 and Dutch 1997 (Venhorst) isolates, confirming the identity of the virus we sequenced. Phylogenetic analysis based on the complete open reading frame showed that Paderborn is genetically very different from common European laboratory reference strains. Neutralization studies showed that Paderborn is also antigenically very different from common laboratory strains such as Alfort 187. Paderborn is the only recent European CSFV field isolate for which a complete sequence is available, and given Paderborns genetic and antigenic uniqueness, the Paderborn sequence may have practical use for diagnostic and vaccine antigen development.
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Affiliation(s)
- Martin B Oleksiewicz
- Department of Virology, Danish Veterinary Institute, Lindholm DK-4771 Kalvehave, Denmark
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29
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Genomic sequence determination of Classical Swine Fever Virus persistent infection strain. ACTA ACUST UNITED AC 2001. [DOI: 10.1007/bf02850922] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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