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Rawal G, Krueger KM, Yim-im W, Li G, Gauger PC, Almeida MN, Aljets EK, Zhang J. Development, Evaluation, and Clinical Application of PRRSV-2 Vaccine-like Real-Time RT-PCR Assays. Viruses 2023; 15:2240. [PMID: 38005917 PMCID: PMC10675446 DOI: 10.3390/v15112240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2023] [Revised: 11/05/2023] [Accepted: 11/06/2023] [Indexed: 11/26/2023] Open
Abstract
In this study, we developed and validated (1) singleplex real-time RT-PCR assays for specific detection of five PRRSV-2 MLV vaccine viruses (Ingelvac MLV, Ingelvac ATP, Fostera, Prime Pac, and Prevacent) and (2) a four-plex real-time RT-PCR assay (IngelvacMLV/Fostera/Prevacent/XIPC) including the internal positive control XIPC for detecting and distinguishing the three most commonly used vaccines in the USA (Prevacent, Ingelvac MLV, and Fostera). The singleplex and 4-plex vaccine-like PCRs and the reference PCR (VetMAXTM PRRSV NA&EU, Thermo Fisher Scientific, Waltham, MA, USA) did not cross-react with non-PRRSV swine viral and bacterial pathogens. The limits of detection of vaccine-like PCRs ranged from 25 to 50 genomic copies/reactions. The vaccine-like PCRs all had excellent intra-assay and inter-assay repeatability. Based on the testing of 531 clinical samples and in comparison to the reference PCR, the diagnostic sensitivity, specificity, and agreement were in the respective range of 94.67-100%, 100%, and 97.78-100% for singleplex PCRs and 94.94-100%, 100%, and 97.78-100% for the 4-plex PCR, with a CT cutoff of 37. In addition, 45 PRRSV-2 isolates representing different genetic lineages/sublineages were tested with the vaccine-like PCRs and the results were verified with sequencing. In summary, the vaccine-like PCRs specifically detect the respective vaccine-like viruses with comparable performances to the reference PCR, and the 4-plex PCR allows to simultaneously detect and differentiate the three most commonly used vaccine viruses in the same sample. PRRSV-2 vaccine-like PCRs provide an additional tool for detecting and characterizing PRRSV-2.
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Affiliation(s)
| | | | | | | | | | | | | | - Jianqiang Zhang
- Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA; (G.R.); (K.M.K.); (W.Y.-i.); (G.L.); (P.C.G.); (M.N.A.); (E.K.A.)
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Madapong A, Saeng-Chuto K, Tantituvanont A, Nilubol D. Safety of PRRSV-2 MLV vaccines administrated via the intramuscular or intradermal route and evaluation of PRRSV transmission upon needle-free and needle delivery. Sci Rep 2021; 11:23107. [PMID: 34845289 PMCID: PMC8629989 DOI: 10.1038/s41598-021-02444-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 11/15/2021] [Indexed: 11/24/2022] Open
Abstract
Two distinct experiments (Exp) were conducted to evaluate the shedding and efficacy of 2 modified live porcine reproductive and respiratory syndrome virus (PRRSV) type 2 vaccines (MLV) when administered intramuscularly (IM) or intradermally (ID) (Exp A), and the potential of PRRSV transmission using a needle-free device (Exp B). One-hundred fifty-four, 3-week-old castrated-male, pigs were procured from a PRRSV-free herd. In Exp A, 112 pigs were randomly allocated into 4 groups of 21 pigs including IM/Ingelvac MLV (G1), IM/Prime Pac (G2), ID/Prime Pac (G3), and non-vaccination (G4). Twenty-eight remaining pigs were served as non-vaccination, age-matched sentinel pigs. G1 was IM vaccinated once with Ingelvac PRRS MLV (Ing) (Boehringer Ingelheim, Germany). G2 and G3 were IM and ID vaccinated once with a different MLV, Prime Pac PRRS (PP) (MSD Animal Health, The Netherlands), respectively. Following vaccination, an antibody response, IFN-γ-SC, and IL-10 secretion in supernatants of stimulated PBMC were monitored. Sera, tonsils, nasal swabs, bronchoalveolar lavage, urines, and feces were collected from 3 vaccinated pigs each week to 42 days post-vaccination (DPV) and assayed for the presence of PRRSV using virus isolation and qPCR. Age-matched sentinel pigs were used to evaluate the transmission of vaccine viruses and were introduced into vaccinated groups from 0 to 42 DPV. Seroconversion was monitored. In Exp B, 42 pigs were randomly allocated into 5 groups of 3 pigs each including IM/High (T1), ID/High (T2), IM/Low (T3), ID/Low (T4), and NoChal. Twenty-seven remaining pigs were left as non-challenge, age-matched sentinel pigs. The T1 and T2, and T3 and T4 groups were intranasally challenged at approximately 26 days of age with HP-PRRSV-2 at high (106) and low (103 TCID50/ml) doses, respectively. At 7 days post-challenge, at the time of the highest viremia levels of HP-PRRSV-2, T1 and T2, and T3 and T4 groups were IM and ID injected with Diluvac Forte using needles and a need-less device (IDAL 3G, MSD Animal Health, The Netherlands), respectively. Same needles or needle-less devices were used to inject the same volume of Diluvac Forte into sentinel pigs. Seroconversion of sentinels was evaluated. The results demonstrated that PP vaccinated groups (G2 and G3), regardless of the route of vaccination, had ELISA response significantly lower than G1 at 7 and 14 DPV. PP-vaccinated groups (G2 and G3) had significantly higher IFN-γ-SC and lower IL-10 secretion compared to the Ing-vaccinated group (G1). The two different MLV when administered intramuscularly demonstrated the difference in virus distribution and shedding patterns. PP-vaccinated pigs had significantly shortened viremia than the Ing-vaccinated pigs. However, ID-vaccinated pigs had lower virus distribution in organs and body fluids without virus shedding to sentinel pigs. In Exp B, regardless of the challenge dose, sentinel pigs intradermally injected with the same needle-less device used to inject challenged pigs displayed no seroconversion. In contrast, sentinel pigs intramuscularly injected with the same needle used to inject challenged pigs displayed seroconversion. The results demonstrated the transmission of PRRSV by using a needle, but not by using a needle-less device. In conclusion, our results demonstrated that ID vaccination might represent an alternative to improve vaccine efficacy and safety, and may be able to reduce the shedding of vaccine viruses and reduce the iatrogenic transfer of pathogens between animals with shared needles.
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Affiliation(s)
- Adthakorn Madapong
- Department of Veterinary Microbiology, Faculty of Veterinary Science, Chulalongkorn University, Henry Dunant Road, Pathumwan, Bangkok, 10330, Thailand
| | - Kepalee Saeng-Chuto
- Department of Veterinary Microbiology, Faculty of Veterinary Science, Chulalongkorn University, Henry Dunant Road, Pathumwan, Bangkok, 10330, Thailand
| | - Angkana Tantituvanont
- Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Dachrit Nilubol
- Department of Veterinary Microbiology, Faculty of Veterinary Science, Chulalongkorn University, Henry Dunant Road, Pathumwan, Bangkok, 10330, Thailand.
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Iseki H, Kawashima K, Shibahara T, Mase M. Immunity against a Japanese local strain of porcine reproductive and respiratory syndrome virus decreases viremia and symptoms of a highly pathogenic strain. BMC Vet Res 2021; 17:156. [PMID: 33849520 PMCID: PMC8042467 DOI: 10.1186/s12917-021-02863-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 03/27/2021] [Indexed: 02/02/2023] Open
Abstract
Background The type 2 highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV) has spread throughout countries of southeast Asia, where it has caused severe economic losses. Even countries presently free of PRRSV are at high risk for infection and spread of this virus. Some of these countries, including Japan, have broad epidemics of the local type 2 PRRSV, creating chronic pathogenicity in the domestic pig population. The present study aimed to evaluate the protective efficacy of immunity by infection with a Japanese field isolate, EDRD1, against heterologous challenge with a Vietnamese HP-PRRSV field strain. To this end, four groups of PRRSV-negative crossbreed piglets were used for a challenge study. Groups 1 and 2 were inoculated with EDRD1 via the intranasal route. After 26 days, Groups 2 and 3 were inoculated with HP-PRRSV via the same route. Group 4 served as an uninfected control. Blood and oral fluid samples were taken every 3–4 days after HP-PRRSV challenge; on day 16 post-challenge, all pigs were euthanized, and examined pathologically. Results The nucleotide sequence analysis of nonstructural protein 2 gene of EDRD1 and comparison with Vietnamese HP-PRRSV showed that the 39 amino acid deletion sites of EDRD1 was nearly in the same region as the 29 amino acid deletion sites of HP-PRRSV. Immunity conferred by inoculation with EDRD1 dramatically reduced viral load in the sera and tissues besides viral shedding (Group 2) compared with those in pigs infected only with HP-PRRSV (Group 3). The clinical signs and rectal temperature were significantly reduced, and the average daily weight gain was significantly improved in the EDRD1-inoculated pigs (Group 2) compared with the Group 3 pigs. Notably, no viral RNA was detected in various organs of the Group 2 pigs 16 days post-infection with HP-PRRSV, except in one pig. Therefore, the immunity induced by EDRD1 and its genetically close field isolates may play a role in reducing viremia caused by HP-PRRSV. Conclusions The results of the present study demonstrate that pigs are highly protected against heterologous Vietnamese HP-PRRSV challenge by immunity against a Japanese local strain, EDRD1.
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Affiliation(s)
- Hiroshi Iseki
- Division of Viral Disease and Epidemiology, National Institute of Animal Health, National Agriculture and Food Research Organization, 3-1-5 Kannondai, Tsukuba, Ibaraki, 305-0856, Japan.
| | - Kenji Kawashima
- Division of Viral Disease and Epidemiology, National Institute of Animal Health, National Agriculture and Food Research Organization, 3-1-5 Kannondai, Tsukuba, Ibaraki, 305-0856, Japan
| | - Tomoyuki Shibahara
- Division of Pathology and Pathophysiology, National Institute of Animal Health, National Agriculture and Food Research Organization, 3-1-5 Kannondai, Tsukuba, Ibaraki, 305-0856, Japan.,Department of Veterinary Science, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-58 Rinku-oraikita, Izumisano, Osaka, 598-8531, Japan
| | - Masaji Mase
- Division of Viral Disease and Epidemiology, National Institute of Animal Health, National Agriculture and Food Research Organization, 3-1-5 Kannondai, Tsukuba, Ibaraki, 305-0856, Japan.,United Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagido, Gifu, Gifu, 501-1193, Japan
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Jeong J, Kim S, Park C, Kang I, Park KH, Ham HJ, Chae C. Effect of vaccination with a porcine reproductive and respiratory syndrome subunit vaccine on sow reproductive performance in endemic farms. Vet Rec 2018; 182:602. [DOI: 10.1136/vr.104547] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 01/29/2018] [Accepted: 02/25/2018] [Indexed: 11/04/2022]
Affiliation(s)
- Jiwoon Jeong
- Department of Veterinary Pathology; College of Veterinary Medicine, Seoul National University; Seoul Republic of Korea
| | - Seeun Kim
- Department of Veterinary Pathology; College of Veterinary Medicine, Seoul National University; Seoul Republic of Korea
| | - Changhoon Park
- Department of Veterinary Pathology; College of Veterinary Medicine, Seoul National University; Seoul Republic of Korea
| | - Ikjae Kang
- Department of Veterinary Pathology; College of Veterinary Medicine, Seoul National University; Seoul Republic of Korea
| | - Kee Hwan Park
- Department of Veterinary Pathology; College of Veterinary Medicine, Seoul National University; Seoul Republic of Korea
| | - Hee Jin Ham
- College of Liberal Arts, Anyang University; Anyang Republic of Korea
| | - Chanhee Chae
- Department of Veterinary Pathology; College of Veterinary Medicine, Seoul National University; Seoul Republic of Korea
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Zhou L, Yang B, Xu L, Jin H, Ge X, Guo X, Han J, Yang H. Efficacy evaluation of three modified-live virus vaccines against a strain of porcine reproductive and respiratory syndrome virus NADC30-like. Vet Microbiol 2017; 207:108-116. [PMID: 28757009 DOI: 10.1016/j.vetmic.2017.05.031] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 05/30/2017] [Accepted: 05/31/2017] [Indexed: 12/15/2022]
Abstract
Porcine reproductive and respiratory syndrome reproductive virus is a devastating pathogen causing tremendous economic losses to swine production worldwide. Emergence of novel and variant PRRSV strains always leads to variable protection efficacy of modified-live virus (MLV) vaccines. Prevalence of PRRSV NADC30-like recently emerging in China has brought about clinical outbreaks of the disease. In the present study, the pathogenicity of a NADC30-like strain CHsx1401 for piglets was analyzed, and the potential cross-protective efficacy of three MLV vaccines including two commercial MLV vaccines and an attenuated low pathogenic PRRSV against this virus was further evaluated in piglets. The NADC30-like CHsx1401 was shown to cause fever, respiratory clinical signs, and lung gross and microscopic lesions of the inoculated piglets, suggesting that this virus is moderate virulent for piglets. Vaccination of piglets with the MLV vaccines could not reduce the clinical signs and lung lesions, and was partially efficacious in the reduction of viral loads in sera upon NADC30-like CHsx1401 challenge, indicating that these three MLV vaccines provide extremely limited cross-protection efficacy against the NADC30-like virus infection. Additionally, Ingelvac PRRS MLV appeared to exert some beneficial efficiency in shortening the period of clinical fever and in improving the growth performance of the challenged pigs. Our findings give valuable guidance for the choice and use of PRRSV MLV vaccines to control NADC30-like virus infection in the field.
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Affiliation(s)
- Lei Zhou
- Key Laboratory of Animal Epidemiology and Zoonosis of Ministry of Agriculture, College of Veterinary Medicine and State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing, People's Republic of China
| | - Beina Yang
- Key Laboratory of Animal Epidemiology and Zoonosis of Ministry of Agriculture, College of Veterinary Medicine and State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing, People's Republic of China
| | - Lei Xu
- Key Laboratory of Animal Epidemiology and Zoonosis of Ministry of Agriculture, College of Veterinary Medicine and State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing, People's Republic of China
| | - Huan Jin
- Key Laboratory of Animal Epidemiology and Zoonosis of Ministry of Agriculture, College of Veterinary Medicine and State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing, People's Republic of China
| | - Xinna Ge
- Key Laboratory of Animal Epidemiology and Zoonosis of Ministry of Agriculture, College of Veterinary Medicine and State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing, People's Republic of China
| | - Xin Guo
- Key Laboratory of Animal Epidemiology and Zoonosis of Ministry of Agriculture, College of Veterinary Medicine and State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing, People's Republic of China
| | - Jun Han
- Key Laboratory of Animal Epidemiology and Zoonosis of Ministry of Agriculture, College of Veterinary Medicine and State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing, People's Republic of China
| | - Hanchun Yang
- Key Laboratory of Animal Epidemiology and Zoonosis of Ministry of Agriculture, College of Veterinary Medicine and State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing, People's Republic of China.
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Do HQ, Trinh DT, Nguyen TL, Vu TTH, Than DD, Van Lo T, Yeom M, Song D, Choe S, An DJ, Le VP. Molecular evolution of type 2 porcine reproductive and respiratory syndrome viruses circulating in Vietnam from 2007 to 2015. BMC Vet Res 2016; 12:256. [PMID: 27855667 PMCID: PMC5112882 DOI: 10.1186/s12917-016-0885-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 11/10/2016] [Indexed: 11/24/2022] Open
Abstract
Background Porcine respiratory and reproductive syndrome (PRRS) virus is one of the most economically significant pathogens in the Vietnamese swine industry. ORF5, which participates in many functional processes, including virion assembly, entry of the virus into the host cell, and viral adaptation to the host immune response, has been widely used in molecular evolution and phylogeny studies. Knowing of molecular evolution of PRRSV fields strains might contribute to PRRS control in Vietnam. Results The results showed that phylogenetic analysis indicated that all strains belonged to sub-lineages 8.7 and 5.1. The nucleotide and amino acid identities between strains were 84.5–100% and 82–100%, respectively. Furthermore, the results revealed differences in nucleotide and amino acid identities between the 2 sub-lineage groups. N-glycosylation prediction identified 7 potential N-glycosylation sites and 11 glycotypes. Analyses of the GP5 sequences, revealed 7 sites under positive selective pressure and 25 under negative selective pressure. Conclusions Phylogenetic analysis based on ORF5 sequence indicated the diversity of PRRSV in Vietnam. Furthermore, the variance of N-glycosylation sites and position under selective pressure were demonstrated. This study expands existing knowledge on the genetic diversity and evolution of PRRSV in Vietnam and assists the effective strategies for PRRS vaccine development in Vietnam. Electronic supplementary material The online version of this article (doi:10.1186/s12917-016-0885-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Hai Quynh Do
- Faculty of Veterinary Medicine, Vietnam National University of Agriculture, Hanoi, Vietnam
| | - Dinh Thau Trinh
- Faculty of Veterinary Medicine, Vietnam National University of Agriculture, Hanoi, Vietnam
| | - Thi Lan Nguyen
- Faculty of Veterinary Medicine, Vietnam National University of Agriculture, Hanoi, Vietnam
| | - Thi Thu Hang Vu
- Research and Development Laboratory, Avac Vietnam Company Limited (AVAC), Hung Yen, Vietnam
| | - Duc Duong Than
- Research and Development Laboratory, Avac Vietnam Company Limited (AVAC), Hung Yen, Vietnam
| | - Thi Van Lo
- Research and Development Laboratory, Avac Vietnam Company Limited (AVAC), Hung Yen, Vietnam
| | - Minjoo Yeom
- College of Pharmacy, Korea University, Sejong, Republic of Korea
| | - Daesub Song
- College of Pharmacy, Korea University, Sejong, Republic of Korea
| | - SeEun Choe
- Animal and Plant Quarantine Agency, Gyeonggi-do, Gimcheon, Gyeongsangbukdo, Republic of Korea
| | - Dong-Jun An
- Animal and Plant Quarantine Agency, Gyeonggi-do, Gimcheon, Gyeongsangbukdo, Republic of Korea
| | - Van Phan Le
- Faculty of Veterinary Medicine, Vietnam National University of Agriculture, Hanoi, Vietnam.
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Madapong A, Temeeyasen G, Saeng-Chuto K, Tripipat T, Navasakuljinda W, Boonsoongnern A, Tantituvanont A, Nilubol D. Humoral immune responses and viral shedding following vaccination with modified live porcine reproductive and respiratory syndrome virus vaccines. Arch Virol 2016; 162:139-146. [PMID: 27695957 DOI: 10.1007/s00705-016-3084-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 09/20/2016] [Indexed: 11/26/2022]
Abstract
The antibody response and pattern of shedding of vaccine virus following vaccination with modified live genotype I or II porcine reproductive and respiratory syndrome virus (PRRSV) vaccines (MLVs) were investigated. Ninety PRRSV-free pigs were divided randomly seven, groups including the NEG, EU1, EU2, US1, US2, US3 and US4 groups. The NEG group was unvaccinated. The EU1, EU2, US1, US2, US3 and US4 groups were vaccinated with the following MLVs: AMERVAC® PRRS, Porcillis® PRRS, Fostera™ PRRS, Ingelvac® PRRS MLV, Ingelvac® PRRS ATP, and PrimePac™ PRRS+ , respectively. Sera were quantitatively assayed for viral RNA using qPCR. Antibody responses were measured using Idexx ELISA and serum neutralization (SN). Shedding of vaccine virus was investigated using sentinel pigs and by detection of viral RNA in tonsil scrapings. Antibody responses were detected by ELISA at 7-14 days post-vaccination (DPV) and persisted at high titers until 84 DPV in all MLV groups. The SN titers were delayed and isolate-specific. SN titers were higher for the homologous virus than for heterologous viruses. Age-matched sentinel pigs introduced into the EU2, US2 and US3 groups at 60 DPV seroconverted. In contrast, sentinel pigs introduced at 84 DPV remained negative in all of the MLV groups. Vaccine viral RNA was detected in tonsil scrapings from the EU2, US2 and US3 groups at 84-90 DPV. No viral RNA was detected beyond 70 DPV in the EU1, US1 and US4 groups. In conclusion, all MLV genotypes induced rapid antibody responses, which were measured using ELISA. The development of SN antibodies was delayed and isolate-specific. However, the shedding pattern was variable and depended on the by virus isolate used to manufacture the vaccine.
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Affiliation(s)
- Adthakorn Madapong
- Department of Veterinary Microbiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Gun Temeeyasen
- Department of Veterinary Microbiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Kepalee Saeng-Chuto
- Department of Veterinary Microbiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Thitima Tripipat
- Department of Veterinary Microbiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, 10330, Thailand
| | | | - Alongkot Boonsoongnern
- Department of Farm Resources and Production Medicine, Faculty of Veterinary Medicine Kamphaeng Saen Campus, Kasetsart University, Nakhon Pathom, Thailand
| | - Angkana Tantituvanont
- Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Dachrit Nilubol
- Department of Veterinary Microbiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, 10330, Thailand.
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Chen Y, He S, Sun L, Luo Y, Sun Y, Xie J, Zhou P, Su S, Zhang G. Genetic variation, pathogenicity, and immunogenicity of highly pathogenic porcine reproductive and respiratory syndrome virus strain XH-GD at different passage levels. Arch Virol 2015; 161:77-86. [PMID: 26483282 DOI: 10.1007/s00705-015-2597-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 09/02/2015] [Indexed: 02/01/2023]
Abstract
Porcine reproductive and respiratory syndrome (PRRS) is one of the most economically important infectious diseases of swine worldwide. Immunization with an attenuated vaccine is considered an effective method for reducing the economic losses resulting from porcine reproductive and respiratory syndrome virus (PRRSV) infection. Several studies have shown that PRRSV can be attenuated by passage in Marc-145 cells, but it is still not clear whether this attenuation influences the immunogenicity of PRRSV and what the mechanism of attenuation is. In order to study the mechanism of attenuation and immunogenicity of highly pathogenic (HP) PRRSV, the HP-PRRSV strain XH-GD was serially 122 times passaged in Marc-145 cells. Genomic sequence comparisons were made at selected passages. To explore the differences in pathogenicity and immunogenicity at different passages, three passages (P5, P62 and P122) were selected for an animal challenge experiment, which showed that passage in Marc-145 cells resulted in attenuation of the virus. After 122 passages, 35 amino acid changes were observed in the structural proteins and non-structural proteins. The animal challenge experiment showed that pathogenicity decreased with increasing passage number. The N antibody level and specific neutralizing (SN) antibody titers also decreased with increasing passage number in the late stage of the animal experiment. This study indicated that the virulence of XH-GD was decreased by passage in Marc-145 cells and that overattenuation might influence the immunogenicity of virus. These results might contribute to our understanding of the mechanism of attenuation.
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Affiliation(s)
- Yao Chen
- MOA Key Laboratory of Animal Vaccine Development, Ministry of China, College of Veterinary Medicine, South China Agricultural University, 483 Wushan Road, Tianhe District, Guangzhou, 510642, China
| | - Shuyi He
- MOA Key Laboratory of Animal Vaccine Development, Ministry of China, College of Veterinary Medicine, South China Agricultural University, 483 Wushan Road, Tianhe District, Guangzhou, 510642, China
| | - Long Sun
- MOA Key Laboratory of Animal Vaccine Development, Ministry of China, College of Veterinary Medicine, South China Agricultural University, 483 Wushan Road, Tianhe District, Guangzhou, 510642, China
| | - Yongfeng Luo
- MOA Key Laboratory of Animal Vaccine Development, Ministry of China, College of Veterinary Medicine, South China Agricultural University, 483 Wushan Road, Tianhe District, Guangzhou, 510642, China
| | - Yankuo Sun
- MOA Key Laboratory of Animal Vaccine Development, Ministry of China, College of Veterinary Medicine, South China Agricultural University, 483 Wushan Road, Tianhe District, Guangzhou, 510642, China
| | - Jiexiong Xie
- MOA Key Laboratory of Animal Vaccine Development, Ministry of China, College of Veterinary Medicine, South China Agricultural University, 483 Wushan Road, Tianhe District, Guangzhou, 510642, China
| | - Pei Zhou
- Guangdong Provincial Key Laboratory of Prevention and Control for Severe Clinical Animal Diseases, College of Veterinary Medicine, South China Agricultural University, 483 Wushan Road, Tianhe District, Guangzhou, 510642, China
| | - Shuo Su
- Guangdong Provincial Key Laboratory of Prevention and Control for Severe Clinical Animal Diseases, College of Veterinary Medicine, South China Agricultural University, 483 Wushan Road, Tianhe District, Guangzhou, 510642, China
| | - Guihong Zhang
- MOA Key Laboratory of Animal Vaccine Development, Ministry of China, College of Veterinary Medicine, South China Agricultural University, 483 Wushan Road, Tianhe District, Guangzhou, 510642, China.
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