Demonstration of Porcine Circovirus Type 2 Inactivation by the Low pH Step of the Trypsin Manufacturing Process Using a New Infectivity Assay

Background:Porcine circovirus and Mycoplasma hyopneumoniae can cause respiratory diseases in pigs, which cause serious economic loss in the worldwide pig industry. Currently, these infections are mainly prevented and controlled by vaccination. The new vaccines on the market are mainly composed of subunits and inactivated vaccines but usually have lower antigenicity than traditional live vaccines. Thus, there is an increasing need to develop new adjuvants that can cause rapid and long-lasting immunity to enhance the antigenic efficacy for vaccines. Studies have shown that meningococcal porin PorB can act as a ligand to combine with Toll-like receptors to activate the production of immunological projections and act as a vaccine immunological adjuvant.Objective:In this article, we expressed and purified the recombinant PorB protein and verified its immunogenicity against porcine circovirus type 2 and Mycoplasma hyopneumoniae genetically engineered vaccine.Methods:In this article, we used prokaryotic expression to express and purify recombinant PorB protein, four different concentrations of PorB protein, Freund's adjuvant with two genetically engineered vaccines were combined with subcutaneous immunization of mice.Results:Our study shows that the appropriate dose of the recombinant protein PorB can enhance the levels of humoral and cellular responses induced by two genetically engineered vaccines in a short period of time in mice. The PorB adjuvant group may cause statistically higher antibody titers for both genetically engineered vaccines compared to Freund's commercial adjuvant (P<0.001).Conclusion:The recombinant protein PorB may be a good candidate adjuvant for improving the protective effect of vaccines against porcine circovirus type 2 and Mycoplasma hyopneumoniae, and the protein can be used for future practical applications.

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A 14 bp indel polymorphism in the promoter region is associated with different responses to porcine circovirus type 2 infection by regulating MRC1 transcription

Veterinary Immunology and Immunopathology ◽

10.1016/j.vetimm.2021.110202 ◽

2021 ◽

Vol 234 ◽

pp. 110202

Author(s):

Hao Liu ◽

Changying Wang ◽

Gen Liu ◽

Yanping Li ◽

Li Kang ◽

...

Keyword(s):

Promoter Region ◽

Porcine Circovirus Type ◽

Porcine Circovirus Type 2 ◽

Porcine Circovirus ◽

Indel Polymorphism

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A Comparison of Virulence of Three Porcine Circovirus Type 2 (PCV2) Genotypes (a, b, and d) in Pigs Singularly Inoculated with PCV2 and Dually Inoculated with PCV2 and Porcine Reproductive and Respiratory Syndrome Virus

Pathogens ◽

10.3390/pathogens10070891 ◽

2021 ◽

Vol 10 (7) ◽

pp. 891

Author(s):

Jeongmin Suh ◽

Taehwan Oh ◽

Keehwan Park ◽

Siyeon Yang ◽

Hyejean Cho ◽

...

Keyword(s):

Porcine Circovirus Type ◽

Porcine Circovirus Type 2 ◽

Daily Weight Gain ◽

Porcine Circovirus ◽

Respiratory Syndrome Virus ◽

Average Daily Weight Gain ◽

Significant Difference ◽

Lesion Severity ◽

Severe Lung

The aim of this study was to compare the virulence of porcine circovirus type 2 (PCV2) genotypes in dually inoculated pigs with both three genotypes (a, b, and d) of PCV2 and porcine reproductive and respiratory syndrome virus-2 (PRRSV-2) versus pigs singularly inoculated with the same three PCV2 genotypes (a, b, and d). Differences in this comparison were found in PCV2 viremia levels, lung and lymphoid lesion severity, and the amount of PCV2 antigen within the lymphoid lesions. Regardless of PCV2 genotypes, pigs that were dually inoculated with PCV2/PRRSV had significantly higher clinical scores, less average daily weight gain, higher levels of PCV2 viremia, and more severe lug and lymphoid lesions compared to pigs singularly inoculated with PCV2. Among the dually infected pig groups, pigs infected with PCV2d/PRRSV-2 had significantly higher levels of PCV2 viremia, more severe lung and lymphoid lesions, and more PCV2-positive cells within lymphoid lesions compared to pigs dually inoculated with PCV2a/PRRSV-2 and PCV2b/PRRSV-2. The results of this study demonstrated significant differences in the virulence among dual inoculation of PCV2a/PRRSV-2, PCV2b/PRRSV-2, and PCV2d/PRRSV-2. A significant difference in the virulence among PCV2a, PCV2b, and PCV2d single-inoculated pig groups was not found with respect to the levels of PCV2 viremia and production of PCV2-associated lymphoid lesions.

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Discriminating the eight genotypes of the porcine circovirus type 2 with TaqMan-based real-time PCR

Virology Journal ◽

10.1186/s12985-021-01541-z ◽

2021 ◽

Vol 18 (1) ◽

Author(s):

Ellen Kathrin Link ◽

Matthias Eddicks ◽

Liangliang Nan ◽

Mathias Ritzmann ◽

Gerd Sutter ◽

...

Keyword(s):

Real Time ◽

Real Time Pcr ◽

Porcine Circovirus Type ◽

Porcine Circovirus Type 2 ◽

Diagnostic Sensitivity ◽

Locked Nucleic Acid ◽

Porcine Circovirus ◽

Amplification Efficiency ◽

Pcr Assays

Abstract Background The porcine circovirus type 2 (PCV2) is divided into eight genotypes including the previously described genotypes PCV2a to PCV2f and the two new genotypes PCV2g and PCV2h. PCV2 genotyping has become an important task in molecular epidemiology and to advance research on the prophylaxis and pathogenesis of PCV2 associated diseases. Standard genotyping of PCV2 is based on the sequencing of the viral genome or at least of the open reading frame 2. Although, the circovirus genome is small, classical sequencing is time consuming, expensive, less sensitive and less compatible with mass testing compared with modern real-time PCR assays. Here we report about a new PCV2 genotyping method using qPCR. Methods Based on the analysis of several hundred PCV2 full genome sequences, we identified PCV2 genotype specific sequences or single-nucleotide polymorphisms. We designed six TaqMan PCR assays that are specific for single genotypes PCV2a to PCV2f and two qPCRs targeting two genotypes simultaneously (PCV2g/PCV2d and PCV2h/PCV2c). To improve specific binding of oligonucleotide primers and TaqMan probes, we used locked nucleic acid technology. We evaluated amplification efficiency, diagnostic sensitivity and tested assay specificity for the respective genotypes. Results All eight PCV2 genotype specific qPCRs demonstrated appropriate amplification efficiencies between 91 and 97%. Testing samples from an epidemiological field study demonstrated a diagnostic sensitivity of the respective genotype specific qPCR that was comparable to a highly sensitive pan-PCV2 qPCR system. Genotype specificity of most qPCRs was excellent. Limited unspecific signals were obtained when a high viral load of PCV2b was tested with qPCRs targeting PCV2d or PCV2g. The same was true for the PCV2a specific qPCR when high copy numbers of PCV2d were tested. The qPCR targeting PCV2h/PCV2c showed some minor cross-reaction with PCV2d, PCV2f and PCV2g. Conclusion Genotyping of PCV2 is important for routine diagnosis as well as for epidemiological studies. The introduced genotyping qPCR system is ideal for mass testing and should be a valuable complement to PCV2 sequencing, especially in the case of simultaneous infections with multiple PCV2 genotypes, subclinically infected animals or research studies that require large sample numbers.

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Epidemiological investigation of porcine circovirus type 2 and its coinfection rate in Shandong province in China from 2015 to 2018

BMC Veterinary Research ◽

10.1186/s12917-020-02718-4 ◽

2021 ◽

Vol 17 (1) ◽

Author(s):

Zicheng Ma ◽

Mengda Liu ◽

Zhaohu Liu ◽

Fanliang Meng ◽

Hongyu Wang ◽

...

Keyword(s):

Pseudorabies Virus ◽

Porcine Circovirus Type ◽

Porcine Circovirus Type 2 ◽

Shandong Province ◽

Porcine Circovirus ◽

Respiratory Syndrome Virus ◽

Limited Information ◽

Serum Samples ◽

Diarrhea Virus

Abstract Background Porcine circovirus type 2 (PCV2) is one of the crucial swine viral pathogens, caused porcine circovirus associated diseases (PCVAD). Shandong province is one of the most important pork producing areas and bears a considerable economic loss due to PCVAD. However, there is limited information on epidemiology and coinfection rate of PCV2 with other critical swine diseases in this area, such as porcine reproductive and respiratory syndrome virus (PRRSV), classical swine fever virus (CSFV), Pseudorabies virus (PRV), and porcine epidemic diarrhea virus (PEDV). Results Overall, 89.59% serum samples and 36.98% tissue samples were positive for PCV2 specified ELISA and PCR positive for PCV2, respectively. The coinfection rates of PCV2 with PRRSV, PRV, CSFV, and PEDV were 26.73%, 18.37%, 13.06%, and 3.47%, respectively. Moreover, genetic characteristic of PCV2 were analyzed based on the cap genes showing that PCV2d is the dominant sub-genotype circulating in the province. Conclusions Our findings reveal that PCV2d, as the dominant strain, is prevailing in pig farms in Shandong province at high levels. There was a high frequency of coinfection of PCV2 and PRRSV.

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Porcine circovirus type 2 (PCV2) infection in Hebei Province from 2016 to 2019: a retrospective study

Archives of Virology ◽

10.1007/s00705-021-05085-z ◽

2021 ◽

Author(s):

Lei Han ◽

Guang-fu Yuan ◽

Shao-jie Chen ◽

Fei Dai ◽

Lin-shan Hou ◽

...

Keyword(s):

Retrospective Study ◽

Porcine Circovirus Type ◽

Porcine Circovirus Type 2 ◽

Hebei Province ◽

Pcv2 Infection ◽

Porcine Circovirus

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Porcine Circovirus Type 2 Rep Enhances IL-10 Production in Macrophages via Activation of p38-MAPK Pathway

Viruses ◽

10.3390/v11121141 ◽

2019 ◽

Vol 11 (12) ◽

pp. 1141

Author(s):

Xingchen Wu ◽

Xiaoya Wang ◽

Tengfei Shi ◽

Le Luo ◽

Dan Qiao ◽

...

Keyword(s):

P38 Mapk ◽

Mapk Pathway ◽

Porcine Circovirus Type ◽

Porcine Circovirus Type 2 ◽

Pcv2 Infection ◽

Porcine Circovirus ◽

Rep Proteins ◽

Il10 Promoter ◽

Later Phase

Porcine circovirus type 2 (PCV2) is one of the major threats to pig farms worldwide. Although PCV2 has been identified to promote IL-10 production, the detailed regulatory roles of PCV2 Rep for IL-10 production remain unclear. Herein, we first found that PCV2 Rep, rather than PCV1 Rep, enhanced IL-10 expression at the later phase of PCV2 infection in porcine alveolar macrophages (PAMs). Furthermore, we found that PCV2 Rep directly activated the p38-MAPK pathway to promote transcription factors NF-κB p50 and Sp1 binding to the il10 promoter, but PCV1 Rep did not. During PCV2 infection, however, PCV2 Rep promoted the binding activities of NF-κB p50 and Sp1 with the il10 promoter only at the later phase of PCV2 infection, since Rep proteins only expressed at the later phase of the infection. Moreover, silence of the thymine DNA glycosylase (TDG), a Rep-binding protein, significantly reduced the binding activities of NF-κB p50 and Sp1 with il10 promoter, resulting in the reduction of IL-10 production in PCV2-inoculated PAMs at the later phase of infection. Taken together, our results demonstrate that Rep proteins enhance IL-10 production during PCV2 infection of PAMs via activation of p38-MAPK pathways, in which host TDG is a critical mediator.

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