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The Monoclonal Antibody Recognized the Open Reading Frame Protein in Porcine Circovirus Type 2-Infected Peripheral Blood Mononuclear Cells. Viruses 2020; 12:v12090961. [PMID: 32872497 PMCID: PMC7551997 DOI: 10.3390/v12090961] [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: 08/17/2020] [Accepted: 08/25/2020] [Indexed: 12/17/2022] Open
Abstract
The purpose of this study in the context of the open reading frame 3 (ORF3) protein of porcine circovirus type 2 (PCV2) was especially its location and its relation to the capsid protein and the apoptosis protein in PCV2-infected porcine peripheral blood mononuclear cells (PBMCs). To detect the ORF3 protein, monoclonal antibodies (mAbs) were generated in this study. The mAb 7D3 binds to the ORF3 peptide (residues 35–66) and the native ORF3 protein in PCV2-infected PBMCs, as shown by immunofluorescence assay (IFA). The data show that 3–5% of PBMCs were positive for ORF3 protein or p53 protein. Further, 78–82% of PBMCs were positive for the capsid. This study confirmed the ORF3 protein not only colocalized with the capsid protein but also colocalized with the p53 protein in PBMCs. Immunoassays were conducted in this study to detect the capsid protein, the ORF3 protein, anti-capsid IgG, and anti-ORF3 IgG. The data show the correlation (r = 0.758) of the ORF3 protein and the capsid protein in the blood samples from the PCV2-infected herd. However, each anti-viral protein IgG had a different curve of the profile in the same herd after vaccination. Overall, this study provides a blueprint to explore the ORF3 protein in PCV2-infected PBMCs.
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Schlub TE, Buchmann JP, Holmes EC. A Simple Method to Detect Candidate Overlapping Genes in Viruses Using Single Genome Sequences. Mol Biol Evol 2019; 35:2572-2581. [PMID: 30099499 PMCID: PMC6188560 DOI: 10.1093/molbev/msy155] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Overlapping genes in viruses maximize the coding capacity of their genomes and allow the generation of new genes without major increases in genome size. Despite their importance, the evolution and function of overlapping genes are often not well understood, in part due to difficulties in their detection. In addition, most bioinformatic approaches for the detection of overlapping genes require the comparison of multiple genome sequences that may not be available in metagenomic surveys of virus biodiversity. We introduce a simple new method for identifying candidate functional overlapping genes using single virus genome sequences. Our method uses randomization tests to estimate the expected length of open reading frames and then identifies overlapping open reading frames that significantly exceed this length and are thus predicted to be functional. We applied this method to 2548 reference RNA virus genomes and find that it has both high sensitivity and low false discovery for genes that overlap by at least 50 nucleotides. Notably, this analysis provided evidence for 29 previously undiscovered functional overlapping genes, some of which are coded in the antisense direction suggesting there are limitations in our current understanding of RNA virus replication.
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Affiliation(s)
- Timothy E Schlub
- Sydney School of Public Health, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
| | - Jan P Buchmann
- Marie Bashir Institute for Infectious Diseases and Biosecurity, Charles Perkins Centre, School of Life and Environmental Sciences and Sydney Medical School, The University of Sydney, Sydney, NSW , Australia
| | - Edward C Holmes
- Marie Bashir Institute for Infectious Diseases and Biosecurity, Charles Perkins Centre, School of Life and Environmental Sciences and Sydney Medical School, The University of Sydney, Sydney, NSW , Australia
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Liu X, Ouyang T, Ma T, Ouyang H, Pang D, Ren L. Immunogenicity evaluation of inactivated virus and purified proteins of porcine circovirus type 2 in mice. BMC Vet Res 2018; 14:137. [PMID: 29685143 PMCID: PMC5913788 DOI: 10.1186/s12917-018-1461-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 04/16/2018] [Indexed: 01/08/2023] Open
Abstract
Background Vaccination is considered as an effective and economical way to against PCV2 infection. However, some of commercial available vaccines are based on inactivated viruses, while the others are based on purified protein of PCV2. In the present study, we aimed to compare the immunogenicity of inactivated virus and purified proteins of porcine circovirus type 2 in mice. Results The results showed that positive antiserum titers were significantly increased after second, third and fourth immunization using inactivated PCV2 or purified proteins as coating antigen. Moreover, the inactivated PCV2 induced significantly higher levels of PCV2-specific antibodies than that of PCV2 subunit proteins. After PCV2 wild strain challenged, the average daily gain was comparable with that of mice in the mock group, and the sera from both inactivated PCV2-immunized animals and subunit protein Cap+ORF3 + Rep immunized animals had significantly higher neutralizing antibody titers than that of the PBS group. As expected, the neutralizing antibody in the inactivated PCV2 group was significantly higher than that of the subunit protein group. These results indicated that positive antiserum induced by the inactivated PCV2 had a better reactivity and specificity than that of the positive antiserum induced by the purified proteins. Conclusions The results in the present study demonstrated inactivated PCV2 is more effective than PCV2 subunit proteins in stimulating immune response to against PCV2 infection.
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Affiliation(s)
- Xiaohui Liu
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University, Changchun, Jilin, 130062, China
| | - Ting Ouyang
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University, Changchun, Jilin, 130062, China
| | - Teng Ma
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University, Changchun, Jilin, 130062, China
| | - Hongsheng Ouyang
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University, Changchun, Jilin, 130062, China
| | - Daxin Pang
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University, Changchun, Jilin, 130062, China
| | - Linzhu Ren
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University, Changchun, Jilin, 130062, China.
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Ren L, Chen X, Ouyang H. Interactions of porcine circovirus 2 with its hosts. Virus Genes 2016; 52:437-44. [DOI: 10.1007/s11262-016-1326-x] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Accepted: 03/19/2016] [Indexed: 12/11/2022]
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Peng Z, Ma T, Pang D, Su D, Chen F, Chen X, Guo N, Ouyang T, Ouyang H, Ren L. Expression, purification and antibody preparation of PCV2 Rep and ORF3 proteins. Int J Biol Macromol 2016; 86:277-81. [PMID: 26812108 DOI: 10.1016/j.ijbiomac.2016.01.073] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2015] [Revised: 12/27/2015] [Accepted: 01/21/2016] [Indexed: 11/18/2022]
Abstract
Rep and ORF3 proteins are important functional proteins of porcine circovirus 2 (PCV2). Here, Rep and ORF3 genes were cloned, expressed and used to raise polyclonal antibodies. The result showed the recombinant plasmids of Rep and ORF3 genes constructed in this study were expressed efficiently in the prokaryotic system, and the recombinant proteins had antigenicity and immunogenicity. Furthermore, reactivity and specificity of the antiserums were characterized by western blot and indirect immunofluorescent assays. The results elucidated that polyclonal antiserum prepared with Rep or ORF3 had good reactivity and specificity against PCV2, or the Rep and ORF3 expressed in PK-15 cells, respectively. The Rep protein is promising for PCV2 antibody and vaccine development. These results will be helpful for further studies focusing on pathogenesis of PCV2 and serology diagnostic test or vaccine development against PCV2.
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Affiliation(s)
- Zhiyuan Peng
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University, Changchun, Jilin 130062, China
| | - Teng Ma
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University, Changchun, Jilin 130062, China
| | - Daxin Pang
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University, Changchun, Jilin 130062, China
| | - Dan Su
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University, Changchun, Jilin 130062, China
| | - Fuwang Chen
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University, Changchun, Jilin 130062, China
| | - Xinrong Chen
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University, Changchun, Jilin 130062, China
| | - Ning Guo
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University, Changchun, Jilin 130062, China
| | - Ting Ouyang
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University, Changchun, Jilin 130062, China
| | - Hongsheng Ouyang
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University, Changchun, Jilin 130062, China
| | - Linzhu Ren
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University, Changchun, Jilin 130062, China.
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Gu J, Wang L, Jin Y, Lin C, Wang H, Zhou N, Xing G, Liao M, Zhou J. Characterization of specific antigenic epitopes and the nuclear export signal of the Porcine circovirus 2 ORF3 protein. Vet Microbiol 2016; 184:40-50. [PMID: 26854343 DOI: 10.1016/j.vetmic.2016.01.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2015] [Revised: 12/22/2015] [Accepted: 01/05/2016] [Indexed: 12/19/2022]
Abstract
Porcine circovirus 2 (PCV2) is the etiological agent of postweaning multisystemic wasting syndrome. PCV2 ORF3 protein is a nonstructural protein known to induce apoptosis, but little is known about the biological function of ORF3 protein. Therefore, we undertook this study to map ORF3 protein epitopes recognized by a panel of monoclonal antibodies (mAbs) and to characterize putative nuclear localization (NLS) and nuclear export (NES) sequences in ORF3. The linear epitopes targeted by two previously published mAbs 3B1 and 1H3 and a novel mouse mAb 3C3 were defined using overlapping pools of peptides. Here, we find that ORF3 in PCV2 infected cells contains a conformational epitope targeted by the antibody 3C3, which is distinct from linear epitopes recognized by the antibodies 3B1 and 1H3 in recombinant ORF3 protein. These results suggest that the linear epitope recognized by 3B1 and 1H3 is masked in PCV2 infected cells, and that the conformational epitope is unique to PCV2 infection. Furthermore, we find that ORF3 protein expressed in cytoplasm in early stages of PCV2 infection and then accumulated in nucleus over time. Moreover, we localize a NES at the N-terminus (residues 1-35aa) of ORF3 which plays critical role in nuclear export activity. These findings provide a novel insight that deepens our understanding of the biological function of PCV2 ORF3.
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Affiliation(s)
- Jinyan Gu
- Institute of Immunity and College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, PR China
| | - Lun Wang
- Key Laboratory of Animal Virology, Ministry of Agriculture, Zhejiang University, Hangzhou 310058, PR China
| | - Yulan Jin
- Key Laboratory of Animal Virology, Ministry of Agriculture, Zhejiang University, Hangzhou 310058, PR China
| | - Cui Lin
- Key Laboratory of Animal Virology, Ministry of Agriculture, Zhejiang University, Hangzhou 310058, PR China
| | - Huijuan Wang
- Key Laboratory of Animal Virology, Ministry of Agriculture, Zhejiang University, Hangzhou 310058, PR China
| | - Niu Zhou
- Key Laboratory of Animal Virology, Ministry of Agriculture, Zhejiang University, Hangzhou 310058, PR China
| | - Gang Xing
- Institute of Immunity and College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, PR China
| | - Min Liao
- Key Laboratory of Animal Virology, Ministry of Agriculture, Zhejiang University, Hangzhou 310058, PR China.
| | - Jiyong Zhou
- Institute of Immunity and College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, PR China; Key Laboratory of Animal Virology, Ministry of Agriculture, Zhejiang University, Hangzhou 310058, PR China; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University, Hangzhou 310058, PR China.
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