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Holinka LG, O’Donnell V, Risatti GR, Azzinaro P, Arzt J, Stenfeldt C, Velazquez-Salinas L, Carlson J, Gladue DP, Borca MV. Early protection events in swine immunized with an experimental live attenuated classical swine fever marker vaccine, FlagT4G. PLoS One 2017; 12:e0177433. [PMID: 28542321 PMCID: PMC5443506 DOI: 10.1371/journal.pone.0177433] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 04/27/2017] [Indexed: 11/19/2022] Open
Abstract
Prophylactic vaccination using live attenuated classical swine fever (CSF) vaccines has been a very effective method to control the disease in endemic regions and during outbreaks in previously disease-free areas. These vaccines confer effective protection against the disease at early times post-vaccination although the mechanisms mediating the protection are poorly characterized. Here we present the events occurring after the administration of our in-house developed live attenuated marker vaccine, FlagT4Gv. We previously reported that FlagT4Gv intramuscular (IM) administered conferred effective protection against intranasal challenge with virulent CSFV (BICv) as early as 7 days post-vaccination. Here we report that FlagT4Gv is able to induce protection against disease as early as three days post-vaccination. Immunohistochemical testing of tissues from FlagT4Gv-inoculated animals showed that tonsils were colonized by the vaccine virus by day 3 post-inoculation. There was a complete absence of BICv in tonsils of FlagT4Gv-inoculated animals which had been intranasal (IN) challenged with BICv 3 days after FlagT4Gv infection, confirming that FlagT4Gv inoculation confers sterile immunity. Analysis of systemic levels of 19 different cytokines in vaccinated animals demonstrated an increase of IFN-α three days after FlagT4Gv inoculation compared with mock infected controls.
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Affiliation(s)
- Lauren G. Holinka
- Plum Island Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Greenport, New York, United States of America
| | - Vivian O’Donnell
- Plum Island Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Greenport, New York, United States of America
- Department of Pathobiology and Veterinary Science, University of Connecticut, Storrs, Connecticut, United States of America
| | - Guillermo R. Risatti
- Department of Pathobiology and Veterinary Science, University of Connecticut, Storrs, Connecticut, United States of America
| | - Paul Azzinaro
- Plum Island Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Greenport, New York, United States of America
- Oak Ridge Institute for Science and Education, Oak Ridge, Tennessee, United States of America
| | - Jonathan Arzt
- Plum Island Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Greenport, New York, United States of America
| | - Carolina Stenfeldt
- Plum Island Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Greenport, New York, United States of America
| | - Lauro Velazquez-Salinas
- Plum Island Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Greenport, New York, United States of America
- Oak Ridge Institute for Science and Education, Oak Ridge, Tennessee, United States of America
| | - Jolene Carlson
- Plum Island Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Greenport, New York, United States of America
- Biosecurity Research Institute and Department of Diagnostic Medicine and Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, United States of America
| | - Douglas P. Gladue
- Plum Island Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Greenport, New York, United States of America
| | - Manuel V. Borca
- Plum Island Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Greenport, New York, United States of America
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Xu L, Fan XZ, Zhao QZ, Zhang ZX, Chen K, Ning YB, Zhang QY, Zou XQ, Zhu YY, Li C, Zhang YJ, Wang Q. Effects of Vaccination with the C-Strain Vaccine on Immune Cells and Cytokines of Pigs Against Classical Swine Fever Virus. Viral Immunol 2017; 31:34-39. [PMID: 28514189 DOI: 10.1089/vim.2017.0010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The attenuated C-strain vaccine against classical swine fever virus (CSFV) is one of the safest and most effective attenuated vaccines. However, little is known of the host immune response after vaccination with the C-strain vaccine. Blood samples from vaccinated pigs were collected to evaluate the number of immune cells, the level of specific CSFV antibody, and related cytokines induced by the vaccination of C-strain vaccine. The C-strain nucleic acid was gradually removed and specific antibody to vaccine kept increasing; the amount of the lymphocyte, Tc cell, and Th cell increased; some inflammatory cytokines such as interleukin (IL)-1 and tumor necrosis factor-α mainly showed downregulated trends, but IL-6 and IL-8 were upregulated greatly; IL-2, IL-4, IL-5, IL-12p40, IL-13, interferon (IFN)-I, and Toll-like receptors (TLRs) kept high expression level after 28 days postvaccination (dpv); IFN-γ was upregulated slightly at 5 and 9 dpv, respectively. These results suggest that the C-strain vaccine induces a Th2 cell response to produce the specific antibody. The vaccine virus replicates at very low level. C-strain vaccine burden has close relationship with the expression of TLRs. The overexpression of TLRs initiates the innate immune system to clear up the vaccine. Meanwhile, ILs expressed by immune system induce the differentiation of B cells and produce specific antibody.
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Affiliation(s)
- Lu Xu
- National Classical Swine Fever Reference Laboratory, China Institute of Veterinary Drug Control, Beijing, People's Republic of China
| | - Xue-Zheng Fan
- National Classical Swine Fever Reference Laboratory, China Institute of Veterinary Drug Control, Beijing, People's Republic of China
| | - Qi-Zu Zhao
- National Classical Swine Fever Reference Laboratory, China Institute of Veterinary Drug Control, Beijing, People's Republic of China
| | - Zheng-Xing Zhang
- National Classical Swine Fever Reference Laboratory, China Institute of Veterinary Drug Control, Beijing, People's Republic of China
| | - Kai Chen
- National Classical Swine Fever Reference Laboratory, China Institute of Veterinary Drug Control, Beijing, People's Republic of China
| | - Yi-Bao Ning
- National Classical Swine Fever Reference Laboratory, China Institute of Veterinary Drug Control, Beijing, People's Republic of China
| | - Qian-Yi Zhang
- National Classical Swine Fever Reference Laboratory, China Institute of Veterinary Drug Control, Beijing, People's Republic of China
| | - Xing-Qi Zou
- National Classical Swine Fever Reference Laboratory, China Institute of Veterinary Drug Control, Beijing, People's Republic of China
| | - Yuan-Yuan Zhu
- National Classical Swine Fever Reference Laboratory, China Institute of Veterinary Drug Control, Beijing, People's Republic of China
| | - Cui Li
- National Classical Swine Fever Reference Laboratory, China Institute of Veterinary Drug Control, Beijing, People's Republic of China
| | - Yu-Jie Zhang
- National Classical Swine Fever Reference Laboratory, China Institute of Veterinary Drug Control, Beijing, People's Republic of China
| | - Qin Wang
- National Classical Swine Fever Reference Laboratory, China Institute of Veterinary Drug Control, Beijing, People's Republic of China
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53
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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: 160] [Impact Index Per Article: 22.9] [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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54
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Blome S, Moß C, Reimann I, König P, Beer M. Classical swine fever vaccines-State-of-the-art. Vet Microbiol 2017; 206:10-20. [PMID: 28069290 DOI: 10.1016/j.vetmic.2017.01.001] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2016] [Revised: 12/24/2016] [Accepted: 01/01/2017] [Indexed: 10/20/2022]
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. These vaccines have usually outstanding efficacy and safety but lack differentiability of infected from vaccinated animals (DIVA or marker strategy). In contrast, the first generation of E2 subunit marker vaccines shows constraints in efficacy, application, and production. To overcome these limitations, new generations of marker vaccines are developed. A wide range of approaches have been tried including recombinant vaccines, recombinant inactivated vaccines or subunit vaccines, vector vaccines, and DNA/RNA vaccines. During the last years, especially attenuated deletion vaccines or chimeric constructs have shown potential. At present, especially two new constructs have been intensively tested, the adenovirus-delivered, Semliki Forest virus replicon-vectored marker vaccine candidate "rAdV-SFV-E2" and the pestivirus chimera "CP7_E2alf". The later was recently licensed by the European Medicines Agency. Under field conditions, all marker vaccines have to be accompanied by a potent test system. Particularly this point shows still weaknesses and it is important to embed vaccination in a well-established vaccination strategy and a suitable diagnostic workflow. In summary, conventional vaccines are a standard in terms of efficacy. However, only vaccines with DIVA will allow improved eradication strategies e.g. also under emergency vaccination conditions in free regions. To answer this demand, new generations of marker vaccines have been developed and add now to the tool box of CSF control.
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Affiliation(s)
- Sandra Blome
- 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
| | - 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
| | - Martin Beer
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Suedufer 10, 17493 Greifswald, Insel Riems, Germany.
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Wang X, Mu G, Dang R, Yang Z. Up-regulation of IL-10 upon PRRSV vaccination impacts on the immune response against CSFV. Vet Microbiol 2016; 197:68-71. [PMID: 27938685 DOI: 10.1016/j.vetmic.2016.11.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2016] [Revised: 11/07/2016] [Accepted: 11/09/2016] [Indexed: 10/20/2022]
Abstract
Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) infection negatively impacts the efficacy of classical swine fever virus (CSFV) vaccine. This paper investigates whether the PRRSV vaccine also impacts the CSFV vaccine and if the impact is time-related. Forty-eight piglets born from four sows were divided into five groups (G1-G5). The piglets in G1 to G4 were given PRRSV vaccine at 14, 21, 28 and 35days of age. The G5 group was not vaccinated with the PRRSV. All pigs were given the CSFV vaccine at 35days of age. Immune responses to the CSFV vaccine were evaluated by testing CSFV-specific sera antibodies, lymphocyte proliferation and cytokine secretion. The results demonstrate that the PRRSV vaccine significantly reduces the immune responses of the CSFV vaccination when immunised both vaccines at the same time or with only a one week interval. The PRRSV vaccination induced higher levels of IL-10 expression in the first week and this may be why the CSFV vaccination is immunosuppressed. The findings indicate that a time interval of more than one week is necessary for vaccinated CSF after the PRRSV immunisation.
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Affiliation(s)
- Xinglong Wang
- College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, China.
| | - Guohui Mu
- College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, China
| | - Ruiyi Dang
- College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, China
| | - Zengqi Yang
- College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, China.
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56
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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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57
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Zhang X. Much Higher Case-fatality Rates of Index Cases. Commentary: Differences in the Epidemiology of Human Cases of Avian Influenza A(H7N9) and A(H5N1) Viruses Infection. Front Public Health 2016; 4:116. [PMID: 27378438 PMCID: PMC4913097 DOI: 10.3389/fpubh.2016.00116] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 05/23/2016] [Indexed: 11/29/2022] Open
Affiliation(s)
- Xiaodong Zhang
- Key Laboratory of Zoonosis Research, Ministry of Education, Institute of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun, China; National Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
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58
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Lei JL, Xia SL, Wang Y, Du M, Xiang GT, Cong X, Luo Y, Li LF, Zhang L, Yu J, Hu Y, Qiu HJ, Sun Y. Safety and immunogenicity of a gE/gI/TK gene-deleted pseudorabies virus variant expressing the E2 protein of classical swine fever virus in pigs. Immunol Lett 2016; 174:63-71. [PMID: 27113530 DOI: 10.1016/j.imlet.2016.04.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 04/08/2016] [Accepted: 04/21/2016] [Indexed: 10/21/2022]
Abstract
Classical swine fever (CSF) and pseudorabies (PR) are both major infectious diseases of pigs, causing enormous economic losses to the swine industry in many countries. A marker vaccine that enables differentiation of infected from vaccinated animals (DIVA) is highly desirable for control and eradication of these two diseases in endemic areas. Since late 2011, PR outbreaks have been frequently reported in many Bartha-K61-vaccinated pig farms in China. It has been demonstrated that a pseudorabies virus (PRV) variant with altered antigenicity and increased pathogenicity was responsible for the outbreaks. Previously, we showed that rPRVTJ-delgE/gI/TK, a gE/gI/TK-deleted PRV variant, was safe for susceptible animals and provided a complete protection against lethal PRV variant challenge, indicating that rPRVTJ-delgE/gI/TK can be used as an attractive vaccine vector. To develop a safe bivalent vaccine against CSF and PR, we generated a recombinant virus rPRVTJ-delgE/gI/TK-E2 expressing the E2 protein of classical swine fever virus (CSFV) based on rPRVTJ-delgE/gI/TK and evaluated its safety and immunogenicity in pigs. The results indicated that pigs (n=5) immunized with rPRVTJ-delgE/gI/TK-E2 of different doses did not exhibit clinical signs or viral shedding following immunization, the immunized pigs produced anti-PRV or anti-CSFV neutralizing antibodies and the pigs immunized with 10(6) or 10(5) TCID50 rPRVTJ-delgE/gI/TK-E2 were completely protected against the lethal challenge with either CSFV Shimen strain or variant PRV TJ strain. These findings suggest that rPRVTJ-delgE/gI/TK-E2 is a promising bivalent DIVA vaccine candidate against CSFV and PRV coinfections.
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Affiliation(s)
- Jian-Lin Lei
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China; College of Veterinary Medicine, Gansu Agricultural University, Lanzhou 730070, China
| | - Shui-Li Xia
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China
| | - Yimin Wang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China
| | - Mingliang Du
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China
| | - Guang-Tao Xiang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China
| | - Xin Cong
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China
| | - Yuzi Luo
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China
| | - Lian-Feng Li
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China
| | - Lingkai Zhang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China
| | - Jiahui Yu
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China
| | - Yonghao Hu
- College of Veterinary Medicine, Gansu Agricultural University, Lanzhou 730070, China.
| | - Hua-Ji Qiu
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China.
| | - Yuan Sun
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China.
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Abstract
Classical swine fever is a highly contagious disease that affects domestic and wild pigs worldwide. The causative agent of the disease is Classical swine fever virus (CSFV), which belongs to the genus Pestivirus within the family Flaviviridae. On the genome level, CSFV can be divided into three genotypes with three to four sub-genotypes. Those genotypes can be assigned to distinct geographical regions. Knowledge about CSFV diversity and distribution is important for the understanding of disease dynamics and evolution, and can thus help to design optimized control strategies. For this reason, the geographical pattern of CSFV diversity and distribution are outlined in the presented review. Moreover, current knowledge with regard to genetic virulence markers or determinants and the role of the quasispecies composition is discussed.
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60
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Muñoz-González S, Perez-Simó M, Muñoz M, Bohorquez JA, Rosell R, Summerfield A, Domingo M, Ruggli N, Ganges L. Efficacy of a live attenuated vaccine in classical swine fever virus postnatally persistently infected pigs. Vet Res 2015; 46:78. [PMID: 26159607 PMCID: PMC4496848 DOI: 10.1186/s13567-015-0209-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 05/21/2015] [Indexed: 02/02/2023] Open
Abstract
Classical swine fever (CSF) causes major losses in pig farming, with various degrees of disease severity. Efficient live attenuated vaccines against classical swine fever virus (CSFV) are used routinely in endemic countries. However, despite intensive vaccination programs in these areas for more than 20 years, CSF has not been eradicated. Molecular epidemiology studies in these regions suggests that the virus circulating in the field has evolved under the positive selection pressure exerted by the immune response to the vaccine, leading to new attenuated viral variants. Recent work by our group demonstrated that a high proportion of persistently infected piglets can be generated by early postnatal infection with low and moderately virulent CSFV strains. Here, we studied the immune response to a hog cholera lapinised virus vaccine (HCLV), C-strain, in six-week-old persistently infected pigs following post-natal infection. CSFV-negative pigs were vaccinated as controls. The humoral and interferon gamma responses as well as the CSFV RNA loads were monitored for 21 days post-vaccination. No vaccine viral RNA was detected in the serum samples and tonsils from CSFV postnatally persistently infected pigs for 21 days post-vaccination. Furthermore, no E2-specific antibody response or neutralising antibody titres were shown in CSFV persistently infected vaccinated animals. Likewise, no of IFN-gamma producing cell response against CSFV or PHA was observed. To our knowledge, this is the first report demonstrating the absence of a response to vaccination in CSFV persistently infected pigs.
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Affiliation(s)
- Sara Muñoz-González
- Centre de Recerca en Sanitat Animal (CReSA)-IRTA, Campus de la Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain.
| | - Marta Perez-Simó
- Centre de Recerca en Sanitat Animal (CReSA)-IRTA, Campus de la Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain.
| | - Marta Muñoz
- Centre de Recerca en Sanitat Animal (CReSA)-IRTA, Campus de la Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain.
| | - José Alejandro Bohorquez
- Centre de Recerca en Sanitat Animal (CReSA)-IRTA, Campus de la Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain.
| | - Rosa Rosell
- Centre de Recerca en Sanitat Animal (CReSA)-IRTA, Campus de la Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain. .,Departament d'Agricultura, Ramaderia, Pesca, Alimentació i Medi Natural, (DAAM), Generalitat de Catalunya, Catalunya, Spain.
| | - Artur Summerfield
- Institute of Virology and immunology (IVI), Mittelhäusern, Switzerland.
| | - Mariano Domingo
- Centre de Recerca en Sanitat Animal (CReSA)-IRTA, Campus de la Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain. .,Departament de Sanitat i d'Anatomia Animals, Facultat de Veterinària, UAB, 08193 Bellaterra, Barcelona, Spain.
| | - Nicolas Ruggli
- Institute of Virology and immunology (IVI), Mittelhäusern, Switzerland.
| | - Llilianne Ganges
- Centre de Recerca en Sanitat Animal (CReSA)-IRTA, Campus de la Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain.
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61
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Treatment with interferon-alpha delays disease in swine infected with a highly virulent CSFV strain. Virology 2015; 483:284-90. [PMID: 26004252 DOI: 10.1016/j.virol.2015.04.024] [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] [Received: 02/06/2015] [Revised: 04/21/2015] [Accepted: 04/24/2015] [Indexed: 12/20/2022]
Abstract
Interferon-alpha (IFNα) can effectively inhibit or abort a viral infection within the host. It has been reported that IFN induction and production is hindered during classical swine fever virus (CSFV) infection. Most of those studies have been performed in vitro, making it difficult to elucidate the actual role of IFNs during CSFV infection in swine. Here, we report the effect of IFNα treatment (delivered by a replication defective recombinant human adenovirus type 5, Ad5) in swine experimentally infected with highly virulent CSFV strain Brescia. Treatment with two different subtypes of IFNα delayed the appearance of CSF-related clinical signs and virus replication although it did not prevent lethal disease. This is the first report describing the effect of IFNα treatment during CSFV infection in swine.
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62
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Summerfield A, Ruggli N. Immune Responses Against Classical Swine Fever Virus: Between Ignorance and Lunacy. Front Vet Sci 2015; 2:10. [PMID: 26664939 PMCID: PMC4672165 DOI: 10.3389/fvets.2015.00010] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Accepted: 04/20/2015] [Indexed: 11/14/2022] Open
Abstract
Classical swine fever virus infection of pigs causes disease courses from life-threatening to asymptomatic, depending on the virulence of the virus strain and the immunocompetence of the host. The virus targets immune cells, which are central in orchestrating innate and adaptive immune responses such as macrophages and conventional and plasmacytoid dendritic cells. Here, we review current knowledge and concepts aiming to explain the immunopathogenesis of the disease at both the host and the cellular level. We propose that the interferon type I system and in particular the interaction of the virus with plasmacytoid dendritic cells and macrophages is crucial to understand elements governing the induction of protective rather than pathogenic immune responses. The review also concludes that despite the knowledge available many aspects of classical swine fever immunopathogenesis are still puzzling.
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Affiliation(s)
| | - Nicolas Ruggli
- Institute of Virology and Immunology - IVI , Bern , Switzerland
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63
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Factors affecting the infectivity of tissues from pigs with classical swine fever: Thermal inactivation rates and oral infectious dose. Vet Microbiol 2015; 176:1-9. [DOI: 10.1016/j.vetmic.2014.12.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Revised: 12/02/2014] [Accepted: 12/03/2014] [Indexed: 11/17/2022]
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64
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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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65
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Glycoprotein E2 of classical swine fever virus expressed by baculovirus induces the protective immune responses in rabbits. Vaccine 2014; 32:6607-13. [DOI: 10.1016/j.vaccine.2014.10.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 09/30/2014] [Accepted: 10/06/2014] [Indexed: 11/21/2022]
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66
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Generation and efficacy evaluation of recombinant classical swine fever virus E2 glycoprotein expressed in stable transgenic mammalian cell line. PLoS One 2014; 9:e106891. [PMID: 25198669 PMCID: PMC4157854 DOI: 10.1371/journal.pone.0106891] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Accepted: 08/03/2014] [Indexed: 01/26/2023] Open
Abstract
Classical swine fever virus (CSFV) is the causative agent of classical swine fever (CSF), which is a highly contagious swine disease that causes significant economic loses to the pig industry worldwide. The envelope E2 glycoprotein of CSFV is the most important viral antigen in inducing protective immune response against CSF. In this study, we generated a mammalian cell clone (BCSFV-E2) that could stably produce a secreted form of CSFV E2 protein (mE2). The mE2 protein was shown to be N-linked glycosylated and formed a homodimer. The vaccine efficacy of mE2 was evaluated by immunizing pigs. Twenty-five 6-week-old Landrace piglets were randomly divided into five groups. Four groups were intramuscularly immunized with mE2 emulsified in different adjuvants twice at four-week intervals. One group was used as the control group. All mE2-vaccinated pigs developed CSFV-neutralizing antibodies two weeks after the first vaccination with neutralizing antibody titers ranging from 1∶40 to 1∶320. Two weeks after the booster vaccination, the neutralizing antibody titers increased greatly and ranged from 1∶10,240 to 1∶81,920. At 28 weeks after the booster vaccine was administered, the neutralizing antibody titers ranged from 1∶80 to 1∶10240. At 32 weeks after the first vaccination, pigs in all the groups were challenged with a virulent CSFV strain at a dose of 1×105 TCID50. At two weeks after the challenge, all the mE2-immunized pigs survived and exhibited no obvious symptoms of CSF. The neutralizing antibody titer at this time was 20,480. Unvaccinated pigs in the control group exhibited symptoms of CSF 3–4 days after challenge and were euthanized from 7–9 days after challenge when the pigs became moribund. These results indicate that the mE2 is a good candidate for the development of a safe and effective CSFV subunit vaccine.
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67
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Partial Activation of natural killer and γδ T cells by classical swine fever viruses is associated with type I interferon elicited from plasmacytoid dendritic cells. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2014; 21:1410-20. [PMID: 25080554 DOI: 10.1128/cvi.00382-14] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Vaccination with live attenuated classical swine fever virus (CSFV) vaccines can rapidly confer protection in the absence of neutralizing antibodies. With an aim of providing information on the cellular mechanisms that may mediate this protection, we explored the interaction of porcine natural killer (NK) cells and γδ T cells with CSFV. Both NK and γδ T cells were refractory to infection with attenuated or virulent CSFV, and no stimulatory effects, as assessed by the expression of major histocompatibility complex (MHC) class II (MHC-II), perforin, and gamma interferon (IFN-γ), were observed when the cells were cultured in the presence of CSFV. Coculture with CSFV and myeloid dendritic cells (mDCs) or plasmacytoid dendritic cells (pDCs) showed that pDCs led to a partial activation of both NK and γδ T cells, with upregulation of MHC-II being observed. An analysis of cytokine expression by infected DC subsets suggested that this effect was due to IFN-α secreted by infected pDCs. These results were supported by ex vivo analyses of NK and γδ T cells in the tonsils and retropharyngeal lymph nodes from pigs that had been vaccinated with live attenuated CSFV and/or virulent CSFV. At 5 days postchallenge, there was evidence of significant upregulation of MHC-II but not perforin on NK and γδ T cells, which was observed only following a challenge of the unvaccinated pigs and correlated with increased CSFV replication and IFN-α expression in both the tonsils and serum. Together, these data suggest that it is unlikely that NK or γδ T cells contribute to the cellular effector mechanisms induced by live attenuated CSFV.
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68
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Widén F, Everett H, Blome S, Fernandez Pinero J, Uttenthal A, Cortey M, von Rosen T, Tignon M, Liu L. Comparison of two real-time RT-PCR assays for differentiation of C-strain vaccinated from classical swine fever infected pigs and wild boars. Res Vet Sci 2014; 97:455-7. [PMID: 25017044 DOI: 10.1016/j.rvsc.2014.06.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Revised: 06/05/2014] [Accepted: 06/28/2014] [Indexed: 11/16/2022]
Abstract
Classical swine fever is one of the most important infectious diseases for the pig industry worldwide due to its economic impact. Vaccination is an effective means to control disease, however within the EU its regular use is banned owing to the inability to differentiate infected and vaccinated animals, the so called DIVA principle. This inability complicates monitoring of disease and stops international trade thereby limiting use of the vaccine in many regions. The C-strain vaccine is safe to use and gives good protection. It is licensed for emergency vaccination in the EU in event of an outbreak. Two genetic assays that can distinguish between wild type virus and C-strain vaccines have recently been developed. Here the results from a comparison of these two real-time RT-PCR assays in an interlaboratory exercise are presented. Both assays showed similar performance.
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Affiliation(s)
- F Widén
- Department of Virology, Immunobiology and Parasitology, The National Veterinary Institute (SVA), Uppsala, Sweden.
| | - H Everett
- Virology Department, Animal Health and Veterinary Laboratories Agency (AHVLA), Addlestone, UK
| | - S Blome
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut (FLI), Greifswald-Insel Riems, Germany
| | | | - A Uttenthal
- National Veterinary Institute, Technical University of Denmark (DTU-VET), Lindholm, Kalvehave, Denmark
| | - M Cortey
- Department of Virology, Immunobiology and Parasitology, The National Veterinary Institute (SVA), Uppsala, Sweden
| | - T von Rosen
- National Veterinary Institute, Technical University of Denmark (DTU-VET), Lindholm, Kalvehave, Denmark
| | - M Tignon
- Veterinary and Agrochemical Research Centre CODA-CERVA, Uccle, Brussel, Belgium
| | - L Liu
- Department of Virology, Immunobiology and Parasitology, The National Veterinary Institute (SVA), Uppsala, Sweden
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69
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García-Nicolás O, Quereda JJ, Gómez-Laguna J, Salguero FJ, Carrasco L, Ramis G, Pallarés FJ. Cytokines transcript levels in lung and lymphoid organs during genotype 1 Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) infection. Vet Immunol Immunopathol 2014; 160:26-40. [DOI: 10.1016/j.vetimm.2014.03.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Revised: 03/10/2014] [Accepted: 03/18/2014] [Indexed: 12/24/2022]
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70
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Renson P, Le Dimna M, Gabriel C, Levai R, Blome S, Kulcsar G, Koenen F, Le Potier M. Cytokine and immunoglobulin isotype profiles during CP7_E2alf vaccination against a challenge with the highly virulent Koslov strain of classical swine fever virus. Res Vet Sci 2014; 96:389-95. [DOI: 10.1016/j.rvsc.2014.01.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Revised: 11/27/2013] [Accepted: 01/23/2014] [Indexed: 10/25/2022]
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71
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He DN, Zhang XM, Liu K, Pang R, Zhao J, Zhou B, Chen PY. In vitro inhibition of the replication of classical swine fever virus by porcine Mx1 protein. Antiviral Res 2014; 104:128-35. [PMID: 24500530 DOI: 10.1016/j.antiviral.2014.01.020] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2013] [Revised: 12/01/2013] [Accepted: 01/24/2014] [Indexed: 12/16/2022]
Abstract
Classical swine fever virus (CSFV) is the causative pathogen of classical swine fever (CSF), a highly contagious disease of swine. Mx proteins are interferon-induced dynamin-like GTPases present in all vertebrates with a wide range of antiviral activities. Although Zhao et al. (2011) have reported that human MxA can inhibit CSFV replication, whether porcine Mx1 (poMx1) has anti-CSFV activity remains unknown. In this study, we generated a cell line designated PK-15/EGFP-poMx1 which expressed porcine Mx1 protein constitutively, and we observed that the proliferation of progeny virus in this cell line was significantly inhibited as measured by virus titration, indirect immune fluorescence assay, Q-PCR and Western blot. Furthermore, when PTD-poMx1 fusion protein expressed in Escherichia coli (Zhang et al., 2013) was used to treat CSFV-infected PK-15 cells, the results showed that PTD-poMx1 inhibited CSFV replication in a dose-dependent manner. Additionally, the proliferation of progeny virus was inhibited as measured by virus titration and Q-PCR. Overall, the results demonstrated that poMx1 effectively inhibited CSFV replication, suggesting that poMx1 may be a valuable therapeutic agent against CSFV infection.
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Affiliation(s)
- Dan-ni He
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China
| | - Xiao-min Zhang
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China
| | - Ke Liu
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China
| | - Ran Pang
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China
| | - Jin Zhao
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China
| | - Bin Zhou
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China.
| | - Pu-yan Chen
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China
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72
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Franzoni G, Kurkure NV, Essler SE, Pedrera M, Everett HE, Bodman-Smith KB, Crooke HR, Graham SP. Proteome-wide screening reveals immunodominance in the CD8 T cell response against classical swine fever virus with antigen-specificity dependent on MHC class I haplotype expression. PLoS One 2013; 8:e84246. [PMID: 24376799 PMCID: PMC3871537 DOI: 10.1371/journal.pone.0084246] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Accepted: 11/13/2013] [Indexed: 12/19/2022] Open
Abstract
Vaccination with live attenuated classical swine fever virus (CSFV) vaccines induces a rapid onset of protection which has been associated with virus-specific CD8 T cell IFN-γ responses. In this study, we assessed the specificity of this response, by screening a peptide library spanning the CSFV C-strain vaccine polyprotein to identify and characterise CD8 T cell epitopes. Synthetic peptides were pooled to represent each of the 12 CSFV proteins and used to stimulate PBMC from four pigs rendered immune to CSFV by C-strain vaccination and subsequently challenged with the virulent Brescia strain. Significant IFN-γ expression by CD8 T cells, assessed by flow cytometry, was induced by peptide pools representing the core, E2, NS2, NS3 and NS5A proteins. Dissection of these antigenic peptide pools indicated that, in each instance, a single discrete antigenic peptide or pair of overlapping peptides was responsible for the IFN-γ induction. Screening and titration of antigenic peptides or truncated derivatives identified the following antigenic regions: core₂₄₁₋₂₅₅ PESRKKLEKALLAWA and NS3₁₉₀₂₋₁₉₁₂ VEYSFIFLDEY, or minimal length antigenic peptides: E2₉₉₆₋₁₀₀₃ YEPRDSYF, NS2₁₂₂₃₋₁₂₃₀ STVTGIFL and NS5A₃₀₇₀₋₃₀₇₈ RVDNALLKF. The epitopes are highly conserved across CSFV strains and variable sequence divergence was observed with related pestiviruses. Characterisation of epitope-specific CD8 T cells revealed evidence of cytotoxicity, as determined by CD107a mobilisation, and a significant proportion expressed TNF-α in addition to IFN-γ. Finally, the variability in the antigen-specificity of these immunodominant CD8 T cell responses was confirmed to be associated with expression of distinct MHC class I haplotypes. Moreover, recognition of NS₁₂₂₃₋₁₂₃₀ STVTGIFL and NS3₁₉₀₂₋₁₉₁₂ VEYSFIFLDEY by a larger group of C-strain vaccinated animals showed that these peptides could be restricted by additional haplotypes. Thus the antigenic regions and epitopes identified represent attractive targets for evaluation of their vaccine potential against CSFV.
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Affiliation(s)
- Giulia Franzoni
- Virology Department, Animal Health and Veterinary Laboratories Agency, Addlestone, United Kingdom
- Department of Microbial & Cellular Sciences, University of Surrey, Guildford, United Kingdom
| | - Nitin V. Kurkure
- Virology Department, Animal Health and Veterinary Laboratories Agency, Addlestone, United Kingdom
- Nagpur Veterinary College, Maharashtra Animal & Fishery Sciences University, Nagpur, India
| | - Sabine E. Essler
- Department of Pathobiology, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Miriam Pedrera
- Virology Department, Animal Health and Veterinary Laboratories Agency, Addlestone, United Kingdom
| | - Helen E. Everett
- Virology Department, Animal Health and Veterinary Laboratories Agency, Addlestone, United Kingdom
| | - Kikki B. Bodman-Smith
- Department of Microbial & Cellular Sciences, University of Surrey, Guildford, United Kingdom
| | - Helen R. Crooke
- Virology Department, Animal Health and Veterinary Laboratories Agency, Addlestone, United Kingdom
| | - Simon P. Graham
- Virology Department, Animal Health and Veterinary Laboratories Agency, Addlestone, United Kingdom
- * E-mail:
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73
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Huang YL, Deng MC, Wang FI, Huang CC, Chang CY. The challenges of classical swine fever control: modified live and E2 subunit vaccines. Virus Res 2013; 179:1-11. [PMID: 24211665 DOI: 10.1016/j.virusres.2013.10.025] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Revised: 10/22/2013] [Accepted: 10/25/2013] [Indexed: 01/15/2023]
Abstract
Classical swine fever (CSF) is an economically important, highly contagious disease of swine worldwide. CSF is caused by classical swine fever virus (CSFV), and domestic pigs and wild boars are its only natural hosts. The two main strategies used to control CSF epidemic are systematic prophylactic vaccination and a non-vaccination stamping-out policy. This review compares the protective efficacy of the routinely used modified live vaccine (MLV) and E2 subunit vaccines and summarizes the factors that influence the efficacy of the vaccines and the challenges that both vaccines face to CSF control. Although MLV provide earlier and more complete protection than E2 subunit vaccines, it has the drawback of not allowing differentiation between infected and vaccinated animals (DIVA). The marker vaccine of E2 protein with companion discriminatory test to detect antibodies against E(rns) allows DIVA and is a promising strategy for future control and eradication of CSF. Maternal derived antibody (MDA) is the critical factor in impairing the efficacy of both MLV and E2 subunit vaccines, so the well-designed vaccination programs of sows and piglets should be considered together. Because of the antigen variation among various genotypes of CSFV, antibodies raised by either MLV or subunit vaccine neutralize genotypically homologous strains better than heterologous ones. However, although this is not a major concern for MLV as the induced immune responses can protect pigs against the challenge of various genotypes of CSFVs, it is critical for E2 subunit vaccines. It is thus necessary to evaluate whether the E2 subunit vaccine can completely protect against the current prevalent strains in the field. An ideal new generation of vaccine should be able to maintain the high protective efficiency of MLV and overcome the problem of antigenic variations while allowing for DIVA.
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Affiliation(s)
- Yu-Liang Huang
- Animal Health Research Institute, Council of Agriculture, 376 Chung-Cheng Road, Tansui, New Taipei City 25158, Taiwan
| | - Ming-Chung Deng
- Animal Health Research Institute, Council of Agriculture, 376 Chung-Cheng Road, Tansui, New Taipei City 25158, Taiwan
| | - Fun-In Wang
- School of Veterinary Medicine, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei 10617, Taiwan
| | - Chin-Cheng Huang
- Pingtung Agriculture Biotechnology Park, Council of Agriculture, No. 1 Shennong Road, Dehe Village, Changjhih Township, Pingtung County 90846, Taiwan
| | - Chia-Yi Chang
- Animal Health Research Institute, Council of Agriculture, 376 Chung-Cheng Road, Tansui, New Taipei City 25158, Taiwan.
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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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75
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Assessment of the phenotype and functionality of porcine CD8 T cell responses following vaccination with live attenuated classical swine fever virus (CSFV) and virulent CSFV challenge. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2013; 20:1604-16. [PMID: 23966552 DOI: 10.1128/cvi.00415-13] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Vaccination with live attenuated classical swine fever virus (CSFV) induces solid protection after only 5 days, which has been associated with virus-specific T cell gamma interferon (IFN-γ) responses. In this study, we employed flow cytometry to characterize T cell responses following vaccination and subsequent challenge infections with virulent CSFV. The CD3(+) CD4(-) CD8(hi) T cell population was the first and major source of CSFV-specific IFN-γ. A proportion of these cells showed evidence for cytotoxicity, as evidenced by CD107a mobilization, and coexpressed tumor necrosis factor alpha (TNF-α). To assess the durability and recall of these responses, a second experiment was conducted where vaccinated animals were challenged with virulent CSFV after 5 days and again after a further 28 days. While virus-specific CD4 T cell (CD3(+) CD4(+) CD8α(+)) responses were detected, the dominant response was again from the CD8 T cell population, with the highest numbers of these cells being detected 14 and 7 days after the primary and secondary challenges, respectively. These CD8 T cells were further characterized as CD44(hi) CD62L(-) and expressed variable levels of CD25 and CD27, indicative of a mixed effector and effector memory phenotype. The majority of virus-specific IFN-γ(+) CD8 T cells isolated at the peaks of the response after each challenge displayed CD107a on their surface, and subpopulations that coexpressed TNF-α and interleukin 2 (IL-2) were identified. While it is hoped that these data will aid the rational design and/or evaluation of next-generation marker CSFV vaccines, the novel flow cytometric panels developed should also be of value in the study of porcine T cell responses to other pathogens/vaccines.
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Development and validation of a multiplex, real-time RT PCR assay for the simultaneous detection of classical and African swine fever viruses. PLoS One 2013; 8:e71019. [PMID: 23923045 PMCID: PMC3724773 DOI: 10.1371/journal.pone.0071019] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 06/28/2013] [Indexed: 11/19/2022] Open
Abstract
A single-step, multiplex, real-time polymerase chain reaction (RT-PCR) was developed for the simultaneous and differential laboratory diagnosis of Classical swine fever virus (CSFV) and African swine fever virus (ASFV) alongside an exogenous internal control RNA (IC-RNA). Combining a single extraction methodology and primer and probe sets for detection of the three target nucleic acids CSFV, ASFV and IC-RNA, had no effect on the analytical sensitivity of the assay and the new triplex RT-PCR was comparable to standard PCR techniques for CSFV and ASFV diagnosis. After optimisation the assay had a detection limit of 5 CSFV genome copies and 22 ASFV genome copies. Analytical specificity of the triplex assay was validated using a panel of viruses representing 9 of the 11 CSFV subgenotypes, at least 8 of the 22 ASFV genotypes as well as non-CSFV pestiviruses. Positive and negative clinical samples from animals infected experimentally, due to field exposure or collected from the UK which is free from both swine diseases, were used to evaluate the diagnostic sensitivity and specificity for detection of both viruses. The diagnostic sensitivity was 100% for both viruses whilst diagnostic specificity estimates were 100% for CSFV detection and 97.3% for ASFV detection. The inclusion of a heterologous internal control allowed identification of false negative results, which occurred at a higher level than expected. The triplex assay described here offers a valuable new tool for the differential detection of the causative viruses of two clinically indistinguishable porcine diseases, whose geographical occurrence is increasingly overlapping.
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77
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Renson P, Le Dimna M, Keranflech A, Cariolet R, Koenen F, Le Potier MF. CP7_E2alf oral vaccination confers partial protection against early classical swine fever virus challenge and interferes with pathogeny-related cytokine responses. Vet Res 2013; 44:9. [PMID: 23398967 PMCID: PMC3599443 DOI: 10.1186/1297-9716-44-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Accepted: 12/19/2012] [Indexed: 02/02/2023] Open
Abstract
The conventional C-strain vaccine induces early protection against classical swine fever (CSF), but infected animals cannot be distinguished from vaccinated animals. The CP7_E2alf marker vaccine, a pestivirus chimera, could be a suitable substitute for C-strain vaccine to control CSF outbreaks. In this study, single oral applications of CP7_E2alf and C-strain vaccines were compared for their efficacy to induce protection against a CSF virus (CSFV) challenge with the moderately virulent Bas-Rhin isolate, in pigs as early as two days post-immunization. This work emphasizes the powerful potential of CP7_E2alf vaccine administered orally by a rapid onset of partial protection similar to that induced by the C-strain vaccine. Furthermore, our results revealed that both vaccinations attenuated the effects induced by CSFV on production of the pig major acute phase protein (PigMAP), IFN-α, IL-12, IL-10, and TGF-β1 cytokines. By this interference, several cytokines that may play a role in the pathogeny induced by moderately virulent CSFV strains were revealed. New hypotheses concerning the role of each of these cytokines in CSFV pathogeny are discussed. Our results also show that oral vaccination with either vaccine (CP7_E2alf or C-strain) enhanced CSFV-specific IgG2 production, compared to infection alone. Interestingly, despite the similar antibody profiles displayed by both vaccines post-challenge, the production of CSFV-specific IgG1 and neutralizing antibodies without challenge was lower with CP7_E2alf vaccination than with C-strain vaccination, suggesting a slight difference in the balance of adaptive immune responses between these vaccines.
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Affiliation(s)
- Patricia Renson
- Anses, Ploufragan/Plouzané laboratory, Swine Virology and Immunology Unit, BP53, 22440, Ploufragan, France.
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Li X, Qiu L, Yang Z, Dang R, Wang X. Emergency vaccination alleviates highly pathogenic porcine reproductive and respiratory syndrome virus infection after contact exposure. BMC Vet Res 2013; 9:26. [PMID: 23394440 PMCID: PMC3626546 DOI: 10.1186/1746-6148-9-26] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2012] [Accepted: 02/05/2013] [Indexed: 11/25/2022] Open
Abstract
Background To assess the effectiveness of emergency vaccination for reducing the contact-induced infection and pathological damage caused by the highly pathogenic porcine reproductive and respiratory syndrome virus (HPPRRSV), Twenty pigs were equally divided into four groups. Groups 1, 2 and 3 were housed in one unit, whereas Group 4 was separately housed. Group 1 was challenged with HPPRRSV on day 0. Group 2 and 4 did not receive treatment and were used as the contact-infected and uninfected controls, respectively. Group 3 was treated with the attenuated vaccine at 0 days post-inoculation. The rectal temperatures, clinical signs, pathologic lesions and viraemia of the piglets were detected and evaluated. Results The vaccinated pigs in Group 3 showed less clinical morbidity, viraemia, temperature fluctuations and lung lesions at 14 days post-inoculation, as compared with the contact-infected (Group 2) and experimentally infected (Group 1) pigs. Higher serum IFN-γ levels were detected among the pigs that received emergency immunisation. Thus, IFN-γ may be involved in immunity against HPPRRSV infection. Conclusions These results indicated that emergency vaccination could effectively alleviate HPPRRSV infection during experimental contact exposure. Our findings provide a novel and useful strategy for controlling clinical HPPRRSV.
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Affiliation(s)
- Xiao Li
- College of Veterinary Medicine, Northwest A&F University, Yangling 712100, China
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79
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Comprehensive evaluation of the adenovirus/alphavirus-replicon chimeric vector-based vaccine rAdV-SFV-E2 against classical swine fever. Vaccine 2013; 31:538-44. [DOI: 10.1016/j.vaccine.2012.11.013] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 10/30/2012] [Accepted: 11/03/2012] [Indexed: 11/21/2022]
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80
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Graham SP, Haines FJ, Johns HL, Sosan O, La Rocca SA, Lamp B, Rümenapf T, Everett HE, Crooke HR. Characterisation of vaccine-induced, broadly cross-reactive IFN-γ secreting T cell responses that correlate with rapid protection against classical swine fever virus. Vaccine 2012; 30:2742-8. [PMID: 22366027 DOI: 10.1016/j.vaccine.2012.02.029] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Revised: 02/07/2012] [Accepted: 02/10/2012] [Indexed: 11/25/2022]
Abstract
Live attenuated C-strain classical swine fever viruses (CSFV) provide a rapid onset of protection, but the lack of a serological test that can differentiate vaccinated from infected animals limits their application in CSF outbreaks. Since immunity may precede antibody responses, we examined the kinetics and specificity of peripheral blood T cell responses from pigs vaccinated with a C-strain vaccine and challenged after five days with a genotypically divergent CSFV isolate. Vaccinated animals displayed virus-specific IFN-γ responses from day 3 post-challenge, whereas, unvaccinated challenge control animals failed to mount a detectable response. Both CD4(+) and cytotoxic CD8(+) T cells were identified as the cellular source of IFN-γ. IFN-γ responses showed extensive cross-reactivity when T cells were stimulated with CSFV isolates spanning the major genotypes. To determine the specificity of these responses, T cells were stimulated with recombinant CSFV proteins and a proteome-wide peptide library from a related virus, BVDV. Major cross-reactive peptides were mapped on the E2 and NS3 proteins. Finally, IFN-γ was shown to exert potent antiviral effects on CSFV in vitro. These data support the involvement of broadly cross-reactive T cell IFN-γ responses in the rapid protection conferred by the C-strain vaccine and this information should aid the development of the next generation of CSFV vaccines.
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Affiliation(s)
- Simon P Graham
- Virology Department, Animal Health and Veterinary Laboratories Agency, Addlestone, United Kingdom.
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