Same Dosages of rPRV/XJ5-gI−/gE−/TK− Prototype Vaccine or Bartha-K61 Vaccine Similarly Protects Growing Pigs Against Lethal Challenge of Emerging vPRV/XJ-5 Strain

Ren, Qinghai; Li, Lin; Pan, Haochun; Wang, Xiaobo; Gao, Qingqing; Huan, Changchao; Wang, Jin; Zhang, Wei; Jiang, Lianhe; Gao, Song; Kai, Yan; Chen, Changhai

doi:10.3389/fvets.2022.896689

Cited by 6 publications

(2 citation statements)

References 25 publications

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“…Recently, two publications from China have documented a PRV variant XJ5; inoculation of this strain at a dose of 2 × 10 6 TCID 50 /pig intranasally could also induce respiratory symptoms as well as CNS symptoms and death in 11-12week-old pigs [26,27]. Tese characterization of abovementioned PRV variants may suggest the emergence of PRV with increased virulence in China.…”

Section: Discussionmentioning

confidence: 97%

Characterization of Pseudorabies Virus Associated with Severe Respiratory and Neuronal Signs in Old Pigs

Chen

Fan

Xie

et al. 2023

Transboundary and Emerging Diseases

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Pseudorabies virus (PRV) represents a leading threat to the global pig industry. Generally, pigs exhibit a pronounced age resistance against PRV, and the virus generally does not cause severe clinical signs and even death in old pigs. However, we characterized two PRV strains (HeN21 and HuB20) associated with severe respiratory and neuronal signs in old pigs. Among these two strains, HeN21 was isolated from the tonsil of a 24-week-old pig that died from severe neuronal and respiratory signs in a PRV-outbreak farm where a commercial PRV attenuated vaccine developed based on a PRV variant was used; while, HuB20 was isolated from the lung and lymph node of a 20-week-old with symptoms in another farm where Bartha-K61 vaccine was used. In vitro evaluations in different cell models demonstrated that HeN21 and HuB20 led to similar cytotoxic effects to those caused by PRV variants on PK-15, Vero, and SK-N-SH cells after 30 hours of inoculation. However, HeN21 possessed a higher titer than the other PRV variants from the first to the fifth passage on PK-15 cells and induced plaques with larger size. In vivo assessments in mouse and fattening pig models showed that inoculations of HeN21 and HuB20 caused higher morbidity and mortality and severe pathological damages in tested animals. In particular, challenge of HeN21 led to severe respiratory and neuronal signs in 90-day-old pigs. These two strains displayed higher virus loads on the main organs of challenged mice and pigs. Phylogenetic analysis revealed that HeN21 and HuB20 belonged to genotype II. In addition, recombinant events were identified in the genomes of HeN21 and HuB20, and several events were located within genes associated with PRV virulence. Our data herein may suggest the emergence of novel PRV strains in China.

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Section: Discussionmentioning

confidence: 97%

Characterization of Pseudorabies Virus Associated with Severe Respiratory and Neuronal Signs in Old Pigs

Chen

Fan

Xie

et al. 2023

Transboundary and Emerging Diseases

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“…PR control in China had been relatively stable until the emergence of PRV variant strains in 2011 where infections occurred in pigs even though the animals had been immunized with the Bartha-K61 strain [ 5 , 6 ]. The Bartha-K61 vaccine appeared to provide only suboptimal protection against these variants [ 7 , 8 ], although other studies do show adequate protection against such variants by the Bartha-K61 vaccine strain [ 9 , 10 ]. Irrespective, the generation of vaccines that antigenically more closely match emerging variant PRV strains may represent an added value to control these infections.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of immunogenicity of gene-deleted and subunit vaccines constructed against the emerging pseudorabies virus variants

Zhang

et al. 2023

Virol J

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Background Pseudorabies (PR) (also called Aujeszky’s disease, AD) is a serious infectious disease affecting pigs and other animals worldwide. The emergence of variant strains of pseudorabies virus (PRV) since 2011 has led to PR outbreaks in China and a vaccine that antigenically more closely matches these PRV variants could represent an added value to control these infections. Methods The objective of this study was to develop new live attenuated and subunit vaccines against PRV variant strains. Genomic alterations of vaccine strains were based on the highly virulent SD-2017 mutant strain and gene-deleted strains SD-2017ΔgE/gI and SD-2017ΔgE/gI/TK, which constructed using homologous recombination technology. PRV gB-DCpep (Dendritic cells targeting peptide) and PorB (the outer membrane pore proteins of N. meningitidis) proteins containing gp67 protein secretion signal peptide were expressed using the baculovirus system for the preparation of subunit vaccines. We used experimental animal rabbits to test immunogenicity to evaluate the effect of the newly constructed PR vaccines. Results Compared with the PRV-gB subunit vaccine and SD-2017ΔgE/gI inactivated vaccines, rabbits (n = 10) that were intramuscularly vaccinated with SD-2017ΔgE/gI/TK live attenuated vaccine and PRV-gB + PorB subunit vaccine showed significantly higher anti-PRV-specific antibodies as well as neutralizing antibodies and IFN-γ levels in serum. In addition, the SD-2017ΔgE/gI/TK live attenuated vaccine and PRV-gB + PorB subunit vaccine protected (90–100%) rabbits against homologous infection by the PRV variant strain. No obvious pathological damage was observed in these vaccinated rabbits. Conclusions The SD-2017ΔgE/gI/TK live attenuated vaccine provided 100% protection against PRV variant challenge. Interestingly, the subunit vaccines with gB protein linked to DCpep and PorB protein as adjuvant may also be a promising and effective PRV variant vaccine candidate.

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Molecular epidemiological and genetic characterization of pseudorabies virus in Guangxi, China

Huang,

Qin,

Wang

et al. 2023

Arch Virol

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Pseudorabies virus (PRV) is an important pathogen that can cause harm to the pig population. However, there have been a number of large-scale outbreaks of pseudorabies on Chinese farms where animals have been previously vaccinated with the Bartha-K61 vaccine since 2011. In order to understand the epidemiological trend and genetic variations of PRV in Guangxi province, China, 819 tissue samples were collected from swine farms suspected of PRV infection from 2013-2019. In this study, these were tested for infectious wild strains of PRV. The results showed a positive rate of PRV in Guangxi province of 28.21% (231/819). 36 wild-type PRV strains were successfully isolated from the PRV-positive tissue samples, and a genetic evolutionary analysis was performed based on the gB, gC, gD, gE and TK genes. 30 of the PRV strains were clustered with the Chinese variant strains, HeN1-China-2012 and HLJ8-China-2013. In addition, 5 PRV strains were genetically related to the Chinese classical strains, and one isolate was a recombinant strain of the PRV variant and the vaccine strain, Bartha-K61. Amino acid sequence analysis showed that all 36 PRV strains had characteristic variant sites in the amino acid sequences of the gB, gC, gD and gE proteins. Pathogenicity analysis showed that, compared to the PRV classical strains, the PRV variant strains had a stronger pathogenicity in mice together with a lower LD 50 . Taken together, our results showed that wild-type PRV infections are common in pig farms in the Guangxi province of China, and that the dominant prevalent strains were those of the PRV variants. The PRV variant strains also had a stronger pathogenicity in mice. Our data will provide a useful reference for understanding the prevalence and genetic evolution of PRV in China.

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Same Dosages of rPRV/XJ5-gI−/gE−/TK− Prototype Vaccine or Bartha-K61 Vaccine Similarly Protects Growing Pigs Against Lethal Challenge of Emerging vPRV/XJ-5 Strain

Cited by 6 publications

References 25 publications

Characterization of Pseudorabies Virus Associated with Severe Respiratory and Neuronal Signs in Old Pigs

Characterization of Pseudorabies Virus Associated with Severe Respiratory and Neuronal Signs in Old Pigs

Evaluation of immunogenicity of gene-deleted and subunit vaccines constructed against the emerging pseudorabies virus variants

Molecular epidemiological and genetic characterization of pseudorabies virus in Guangxi, China

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