Comparison of two genetically distant type 2 porcine reproductive and respiratory syndrome virus (PRRSV) modified live vaccines against Vietnamese highly pathogenic PRRSV

Vaccination is the best way to prevent economic losses from highly pathogenic porcine reproductive and respiratory syndrome virus (hp-PRRSV) disease. However, the commercially available vaccines need to periodically evaluate their efficacy against infections caused by new hp-PRRSV variants. Therefore, the objective of this study was to evaluate the efficacy of four (two modified live vaccines (MLV) and two inactivated) PRRSV commercial vaccines in piglets challenged with QH-08 and to estimate the genetic distance of the vaccine strains from recently isolated (QH-08) filed strain. Randomly, piglets (n = 5) allocated in groups 1–4 were immunized with Ingelvac PRRS MLV, CH-1a, JXA1, and JXA1-RMLV vaccines, whereas the infected and non-infected control piglets in groups 5 and 6 (n = 3), respectively, were subjected to PBS. Results indicated that JXA1 and JXA1-R MLV vaccines showed complete protection, but Ingelvac PRRS MLV and CH-1α vaccines revealed partial protection against the QH-08 PRRSV challenge. Similarly, vaccinated and challenged pigs showed lower macroscopic and microscopic lesions than the pigs in group 5. Our findings demonstrated a new insight that the variation in ORF1a and 1b coding sequence could significantly affect PRRSV vaccines efficacy. In conclusion, QH-08 is a good candidate for the design and development of an innovative PRRSV vaccine that ultimately helps in the control and prevention strategies.

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The 30-Amino-Acid Deletion in the Nsp2 of Highly Pathogenic Porcine Reproductive and Respiratory Syndrome Virus Emerging in China Is Not Related to Its Virulence

Journal of Virology ◽

10.1128/jvi.02678-08 ◽

2009 ◽

Vol 83 (10) ◽

pp. 5156-5167 ◽

Cited By ~ 194

Author(s):

Lei Zhou ◽

Jialong Zhang ◽

Jingwen Zeng ◽

Shuoyan Yin ◽

Yanhua Li ◽

...

Keyword(s):

Amino Acid ◽

Parental Virus ◽

Respiratory Syndrome Virus ◽

Cdna Clones ◽

Coding Region ◽

Amino Acid Deletion ◽

Highly Pathogenic ◽

Specific Pathogen ◽

Prrsv Strain ◽

Highly Pathogenic Prrsv

ABSTRACT During the past 2 years, an atypical clinical outbreak, caused by a highly pathogenic porcine reproductive and respiratory syndrome virus (PRRSV) with a unique 30-amino-acid deletion in its Nsp2-coding region, was pandemic in China. In this study, we generated four full-length infectious cDNA clones: a clone of the highly virulent PRRSV strain JXwn06 (pWSK-JXwn), a clone of the low-virulence PRRSV strain HB-1/3.9 (pWSK-HB-1/3.9), a chimeric clone in which the Nsp2 region containing the 30-amino-acid deletion was replaced by the corresponding region of the low-virulence PRRSV strain HB-1/3.9 (pWSK-JXwn-HB1nsp2), and a mutated HB-1/3.9 clone with the same deletion in Nsp2 as JXwn06 (pWSK-HB1-ND30). We also investigated the pathogenicities of the rescued viruses (designated RvJXwn, RvJXwn-HB1nsp2, RvHB-1/3.9, and RvHB1-ND30, respectively) in specific-pathogen-free piglets in order to determine the role of the 30-amino-acid deletion in the virulence of the highly pathogenic PRRSV. All the rescued viruses could replicate stably in MARC-145 cells. Our findings indicated that RvJXwn-HB1nsp2 retained high virulence for piglets, like RvJXwn and the parental virus JXwn06, although the survival time of piglets infected with RvJXwn-HB1nsp2 was obviously prolonged. RvHB1-ND30 exhibited low virulence for piglets, like RvHB-1/3.9 and the parental virus HB-1/3.9. Therefore, we conclude that the 30-amino-acid deletion is not related to the virulence of the highly pathogenic PRRSV emerging in China.

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Immunity against a Japanese local strain of porcine reproductive and respiratory syndrome virus decreases viremia and symptoms of a highly pathogenic strain

BMC Veterinary Research ◽

10.1186/s12917-021-02863-4 ◽

2021 ◽

Vol 17 (1) ◽

Author(s):

Hiroshi Iseki ◽

Kenji Kawashima ◽

Tomoyuki Shibahara ◽

Masaji Mase

Keyword(s):

Amino Acid ◽

Local Strain ◽

Daily Weight Gain ◽

Respiratory Syndrome Virus ◽

Nucleotide Sequence Analysis ◽

Amino Acid Deletion ◽

Highly Pathogenic ◽

Group 3 ◽

Group 2

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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An infectious cDNA clone of a highly pathogenic porcine reproductive and respiratory syndrome virus variant associated with porcine high fever syndrome

Journal of General Virology ◽

10.1099/vir.0.2008/001529-0 ◽

2008 ◽

Vol 89 (9) ◽

pp. 2075-2079 ◽

Cited By ~ 52

Author(s):

Jian Lv ◽

Jianwu Zhang ◽

Zhi Sun ◽

Weiquan Liu ◽

Shishan Yuan

Keyword(s):

Clinical Symptoms ◽

Animal Experiments ◽

High Fever ◽

Respiratory Syndrome Virus ◽

Cdna Clones ◽

Highly Pathogenic ◽

Virus Variant ◽

Recombinant Viruses ◽

Prrsv Strain ◽

Highly Pathogenic Prrsv

Since May 2006, a so-called ‘porcine high fever syndrome’ (PHFS) has spread all over China. The arterivirus porcine reproductive and respiratory syndrome virus (PRRSV) was believed to be the main causative agent, although the involvement of other pathogens was not formally excluded. The genome of a representative Chinese PRRSV strain, named JX143, was sequenced and used to develop infectious cDNA clones, pJX143 and pJX143M, with the latter containing an engineered MluI site that served as a genetic marker. In various virological assays, the rescued viruses, vJX143 and vJX143M, were indistinguishable from their parental virus. Animal experiments showed that these recombinant viruses retained the high pathogenicity and induced the typical clinical symptoms observed during PHFS outbreaks. This is the first report describing infectious cDNA clones of this highly pathogenic PRRSV. Our results unambiguously fulfil Koch's postulates and define highly pathogenic PRRSV as the aetiological agent of PHFS in China.

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Comparison of Two Commercial Type 1 Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) Modified Live Vaccines against Heterologous Type 1 and Type 2 PRRSV Challenge in Growing Pigs

Clinical and Vaccine Immunology ◽

10.1128/cvi.00001-15 ◽

2015 ◽

Vol 22 (6) ◽

pp. 631-640 ◽

Cited By ~ 29

Author(s):

Taeyeon Kim ◽

Changhoon Park ◽

Kyuhyung Choi ◽

Jiwoon Jeong ◽

Ikjae Kang ◽

...

Keyword(s):

Nucleic Acids ◽

Interleukin 10 ◽

Growing Pigs ◽

Respiratory Syndrome Virus ◽

Lung Lesions ◽

Live Vaccines ◽

Immunological Responses ◽

Ifn Γ

ABSTRACTThe objective of the present study was to compare the efficacy of two commercial type 1 porcine reproductive and respiratory syndrome virus (PRRSV) modified live vaccines against heterologous type 1 and type 2 PRRSV challenge in growing pigs. Vaccination with a type 1 PRRSV vaccine reduced the level of viremia after type 1 PRRSV challenge but did not reduce the level of viremia after the type 2 PRRSV challenge in pigs. Increased levels of interleukin-10 (IL-10) stimulated by type 2 PRRSV coincided with the low numbers of type 2 PRRSV-specific interferon gamma-secreting cells (IFN-γ-SC) in vaccinated pigs after type 2 PRRSV challenge, whereas low levels of IL-10 stimulated by type 1 PRRSV coincided with high numbers of type 1 PRRSV-specific IFN-γ-SC in vaccinated pigs after type 1 PRRSV challenge. Additionally, vaccination with the type 1 PRRSV vaccine effectively reduced the lung lesions and type 1 PRRSV nucleic acids in type 1 PRRSV-challenged pigs but did not reduce lung lesions and type 2 PRRSV nucleic acids in type 2 PRRSV-challenged pigs. There were no significant differences between two commercial type 1 PRRSV vaccines against type 1 and type 2 PRRSV challenge based on virological results, immunological responses, and pathological outcomes. This study demonstrates that vaccinating pigs with the type 1 PRRSV vaccine provides partial protection against respiratory disease with heterologous type 1 PRRSV challenge but no protection with heterologous type 2 PRRSV challenge.

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Porcine Reproductive and Respiratory Syndrome Virus Structural Protein GP3 Regulates Claudin 4 To Facilitate the Early Stages of Infection

Journal of Virology ◽

10.1128/jvi.00124-20 ◽

2020 ◽

Vol 94 (20) ◽

Author(s):

Guofei Ding ◽

Jiaqi Liu ◽

Qingyuan Shao ◽

Bin Wang ◽

Jian Feng ◽

...

Keyword(s):

Transcription Factor ◽

Respiratory Syndrome Virus ◽

Structural Protein ◽

Extracellular Loop ◽

Highly Pathogenic ◽

Early Stages ◽

Transcription Factor Sp1 ◽

Viral Particles ◽

Highly Pathogenic Prrsv ◽

Novel Therapeutic

ABSTRACT Claudins (CLDN) are a family of proteins that represent the most important components of tight junctions, where they establish the paracellular barrier that controls the flow of molecules in the intercellular space between epithelial cells. Several types of viruses make full use of CLDN to facilitate entry into cells. Porcine reproductive and respiratory syndrome virus (PRRSV) is one of the most important pathogens in the swine industry. In this study, we found that CLDN4 functions as an anti-PRRSV factor by blocking its absorption during the early stages of infection. The small extracellular loop (ECL2) of CLDN4 restricted the viral particles outside cells by binding to GP3. A novel function of GP3-mediated regulation of CLDN4 transcription was suggested. CLDN4 can be decreased through downregulating the level of CLDN4 transcription by ubiquitinating the transcription factor, SP1. The mechanism by which highly pathogenic PRRSV infects the epithelium was proposed. Importantly, ECL2 was found to block PRRSV absorption and infection and neutralize the virus. A more in-depth understanding of PRRSV infection is described, and novel therapeutic antiviral strategies are discussed. IMPORTANCE In the present study, the role of CLDN4 in PRRSV infection was studied. The results showed that CLDN4 blocked absorption into cells and restricted extracellular viral particles via the interaction between the CLDN4 small extracellular loop, ECL2, and the viral surface protein GP3. GP3 was found to downregulate CLDN4 through ubiquitination of the transcription factor SP1 to facilitate viral entry. The mechanism by which highly pathogenic PRRSV infects the epithelium is suggested. A novel function of GP3 in regulating gene transcription was discovered. Moreover, ECL2 could block PRRSV absorption and infection, as well as neutralizing the virus in the supernatant, which may lead to the development of novel therapeutic antiviral strategies.

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