Generation of E. coli-derived virus-like particles of porcine circovirus type 2 and their use in an indirect IgG enzyme-linked immunosorbent assay

2016 ◽  
Vol 161 (6) ◽  
pp. 1485-1491 ◽  
Author(s):  
Yan Zhang ◽  
Zhanfeng Wang ◽  
Yang Zhan ◽  
Qian Gong ◽  
Wanting Yu ◽  
...  
2000 ◽  
Vol 12 (5) ◽  
pp. 400-405 ◽  
Author(s):  
Ian W. Walker ◽  
Carrie A. Konoby ◽  
Victoria A. Jewhurst ◽  
Irene McNair ◽  
Francis McNeilly ◽  
...  

We report the development of a competitive enzyme-linked immunosorbent assay (c-ELISA) for the detection of antibodies to porcine circovirus type 2 (PCV2), the agent associated with the recently described postweaning multisystemic wasting syndrome in pigs. At present, no method has been published describing a c-ELISA for the detection of antibodies to PCV2, and currently employed tests are impractical for use in some laboratories. The assay described here uses a cell culture isolate of porcine circovirus type 2 as antigen and a PCV2-specific monoclonal antibody as the competing reagent. Evaluation of the ELISA was performed by comparison with results obtained using an indirect immunofluorescent test on 484 sera from pig herds in the United Kingdom, Canada, France, and the USA and serial bleeds from pigs experimentally infected with porcine circoviruses. The sensitivity and specificity of the ELISA were determined as 99.58% and 97.14%, respectively, at 2 standard deviations (SD) from the mean or 95.81% and 100% at 3 SD from the mean. Using this ELISA, a serologic survey of 461 sera collected from commercial pig herds in Northern Ireland between 1973 and 1999 was undertaken. Analysis of the results of this survey demonstrated that the number of ELISA-positive sera detected in an individual year during this period ranged from 55% to 100%. This c-ELISA has applications for large-scale rapid diagnosis of PCV2 infection in pig populations worldwide and for immunoscreening of sera from other species for antibodies to PCV2.


Pathogens ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1564
Author(s):  
Haiqiao Bian ◽  
Chong Yu ◽  
Yanwu Wei ◽  
Li Feng ◽  
Changming Liu ◽  
...  

Porcine circovirus type 2 (PCV2) is a DNA virus without an envelope. The viral particle is icosahedral and has a diameter of approximately 17 nm. In order to obtain the purified virus, a broad-spectrum monoclonal antibody 3A5 against PCV2 was coupled to CNBr-activated SepharoseTM 4B, and an affinity chromatography was established for PCV2 purification. A total of 6.5 mg of purified PCV2a/LG with 97% purity was obtained from 120 mL of the viral culture medium, and only PCV2 was detected by electron microscopy. No significant changes in the antigenic characteristics of the purified virus were detected by a capture enzyme-linked immunosorbent assay (ELISA). Furthermore, the titer of the purified PCV2 was 100 times higher than that of the unpurified virus. This affinity chromatography method was also used to purify PCV2b/LN590516 and PCV2d/SD446F16, and the purified viruses were detected by electron microscopy, capture ELISA, and virus titration, respectively. The results showed that these two strains can be successfully purified, but the yield is lower than that of the PCV2a strain. In addition, the purified virus could be used to study the viral adsorption and invasion of PK15 cells using indirect immunofluorescence assays. A large number of PCV2 signals were detected to transfer from the cellular surface to the periphery of the nucleus of the PK15 cells after 30 min of adsorption of the PCV2 to the PK15 cells. The affinity chromatography is a simple and convenient tool to obtain PCV2 with high purity. It could be applied for virus structure analysis, antibody preparation, and viral adsorption and invasion research.


Author(s):  
Anastasia D. Titova ◽  
Kirill V. Kudzin ◽  
Vladimir A. Prokulevich

To improve expression of the porcine circovirus type 2 (PCV2) capsid protein in E. coli cells, the corresponding gene was optimized and two variants of the open reading frame were constructed, which encoded the full-sized and shortened capsid proteins as part of the expression vector. Rare codons were replaced, and in the case of a shortened version of the gene, the region corresponding to the N-terminal domain of the protein was deleted. A comparison was made of the expression level of the studied proteins. It was established that the highest level of expression in bacterial cells is achieved by simultaneously optimizing the codons and removing the initial (N-terminal) 108 base pair (bp) portion of the gene, which contains the nuclear localization signal.


2020 ◽  
Vol 16 (1) ◽  
Author(s):  
Yu Tao ◽  
Rui Yang ◽  
Jianhong Shu ◽  
Wenqian Zheng ◽  
Jian Chen ◽  
...  

Abstract Background Mycoplasma hyopneumoniae (Mhp) and porcine circovirus type 2 (PCV2) are two important pathogens causing Mycoplasma pneumonia of swine (MPS) and porcine circovirus diseases and porcine circovirus-associated diseases (PCVDs/PCVADs), respectively, and resulted in considerable economic loss to the swine industry worldwide. Currently, vaccination is one of the main measures to control these two diseases; however, there are few combination vaccines that can prevent these two diseases. To determine the effect of combination immunization, we developed capsid-derived (Cap) virus-like particles (VLPs) of PCV2 and a new recombinant chimera composed of the P97R1, P46, and P42 antigens of Mhp. Then we investigated the immune responses induced by the immunization with this combination vaccine in mice and piglets. Results The high level antibodies against three protein antigens (P97R1, P46, and P42 of Mhp) were produced after immunization, up to or higher than 1:400,000; the antibody levels in Pro group continuously increased throughout the 42 days for all the antigens tested. The lymphocyte proliferative response in PCV2 group was stronger than that in PBS, VP, Mhp CV in mice. The antibody levels for Cap remained stable and reached the peak at 35 DAI. The IFN-γ and IL-4 in sera were significantly enhanced in the Pro group than that in the negative control-VP group on Day 14 and 28 post-the first immunization in piglets. Conclusions Above all, the combination immunization could induce humoral and cellular immune responses against all four antigens in mice and piglets. Therefore, our approach is a simple and effective vaccination strategy to protect pigs against MPS and PCVD/PCVAD.


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