• 한국동물위생학회지
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• 제38권3호
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• pp.145-153
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• 2015

In this study, we developed a loop-mediated isothermal amplification (LAMP) with hydroxynaphtol blue dye (HNB) for rapid and direct visual detection of porcine circovirus 2 DNA with high sensitivity and specificity. The LAMP was completed in 40 min at $63^{\circ}C$, and the results of the LAMP can be confirmed by naked eye without any detection process. The sensitivity of the LAMP was 10-fold higher than that of the commercial PCR (cPCR) and real time PCR (rPCR) previously reported. In clinical application, the PCV2 detection rate of the LAMP was the same on porcine tissue samples (75.0%, 36/48) between porcine blood samples (75.0%, 39/52). The PCV2 detection rate (75.0%) of LAMP was higher than those of the cPCR and rPCR (67.3%, 35/52) in blood samples. In conclusion, the LAMP developed in the study could be an useful alternative method for the detection of PCV2 in the swine disease diagnostic laboratories.

• 생명과학회지
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• 제27권3호
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• pp.283-288
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• 2017

양돈산업에 있어 돼지 써코바이러스 2형(PCV2)의 복합감염으로 인한 이유자돈의 질병 피해가 막대하다. PCV2 감염에 대한 숙주의 민감도는 상이한 것으로 알려져 있으며, 따라서 숙주의 민감도를 구분하는 것은, 이를 이용한 숙주의 저항성 향상 연구에 필수이다. 본 연구의 목적은 이유자돈군의 혈액 내에서 PCV2 바이러스에 대한 숙주의 민감도를 구분 짓고 구명하는데 있었다. 본 연구에서는 자연적으로 바이러스에 감염된 10주령의 이유자돈군으로부터 혈청을 채취하여 PCV2 바이러스량과 항체가를 측정하고 혈구분석을 실시했다. 또한, 측정된 PCV2 바이러스량과 항체가를 기준으로 자돈군 내에서 저항성군과 민감성군을 선정하였고, 통계분석결과 저항성군에 비해 민감성군에서 백혈구 수가 현저히 줄어든 것을 확인하였다. 본 연구를 통해서 PCV2 감염에 대한 돼지의 민감도를 구분짓기 위한 PCV2 바이러스량과 항체가를 이용한 복합기준을 제시할 수 있었으며, 이유자돈군의 PCV2 관련 질병저항성 및 백혈구감소증을 확인할 수 있는 방법을 마련하였다.

• 대한수의학회지
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• 제47권2호
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• pp.175-185
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• 2007

This study was carried out to investigate the pathogenesis and pathogenicity of the porcine circovirus type 2 (PCV2) Korean isolate from weaned pigs. Twenty four weaned pigs, PCV2, porcine reproductive and respiratory syndrome virus (PRRSV) and porcine parvovirus (PPV) antibodies free, were allocated to 4 groups (n = 6). Six pigs were inoculated intranasally with PCV2 alone, 6 with PCV2 and PRRSV, 6 with the combined PCV2/PRRSV/PPV inoculum, and 6 were remained as a uninoculated negative control. Pigs were killed 3 and 6 weeks after inoculation and tissue samples examined for gross and microscopic lesions and for the presence of PCV2 antigens and nucleic acids. Experimentally inoculated pigs were evaluated for 3 considerations: 1. development of postweaning multisystemic wasting syndrome (PMWS), 2. distribution of viral antigens by immunohistochemistry and polymerase chain reaction (PCR), and 3. cytokine mRNA levels in lymph nodes. Pigs inoculated with PCV2/PRRSV/PPV showed typical clinical signs, gross findings, and histopathologic characteristics of PMWS. In the PCV2/PRRSV/PPV inoculated group, the PCV2 antigen was widely distributed in various parenchymal organs such as brain, spinal cord, tonsil, lymph nodes, lung, heart, liver, kidney, spleen, and peyer's patch. Lymph node mRNA expression of IL-$1{\alpha}$, IL-2R and IL-8 was determined by real-time PCR. The pigs of PCV2/PRRSV and PCV2/PRRSV/PPV inoculation group, the mRNA expression was characterized by a decrease of IL-$1{\alpha}$, IL-2R and IL-8. The decrease of cytokine mRNA represent the state of T cell immuno-suppression in pig, and nicely support the evidence for the impairment of immune system in pigs with PMWS. In conclusion, PCV2 infection and some additional infectious causes such as PRRSV and/or PPV are warranted for the presence of PMWS in weaned pigs in Korea.

• 한국동물위생학회지
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• 제45권1호
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• pp.1-11
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• 2022

A novel porcine circovirus 4 (PCV4) was recently identified in Chinese and Korean pig herds. Although several conventional polymerase chain reaction (cPCR) and real-time PCR (qPCR) assays were used for PCV4 detection, more sensitive and reliable qPCR assay is needed that can simultaneously detect PCV4 and internal positive control (IPC) to avoid false-negative results. In the present study, a duplex qPCR (dqPCR) assay was developed using primers/probe sets targeting the PCV4 Cap gene and pig (glyceraldehyde-3-phosphate dehydrogenase) GAPDH gene as an IPC. The developed dqPCR assay was specifically detected PCV4 but not other PCVs and porcine pathogens, indicating that the newly designed primers/probe set is specific to the PCV4 Cap gene. Furthermore, GAPDH was stably amplified by the dqPCR in all tested viral and clinical samples containing pig cellular materials, indicating the high reliability of the dqPCR assay. The limit of detection of the assay 5 copies of the target PCV4 genes, but the sensitivity of the assay was higher than that of the previously described assays. The assay demonstrated high repeatability and reproducibility, with coefficients of intra-assay and inter-assay variation of less than 1.0%. Clinical evaluation using 102 diseased pig samples from 18 pig farms showed that PCV4 circulated in the Korean pig population. The detection rate of PCV4 obtained using the newly developed dqPCR was 26.5% (27/102), which was higher than that obtained using the previously described cPCR and TaqMan probe-based qPCR and similar to that obtained using the previously described SYBR Green-based qPCR. The dqPCR assay with IPC is highly specific, sensitive, and reliable for detecting PCV4 from clinical samples, and it will be useful for etiological diagnosis, epidemiological study, and control of the PCV4 infections.

• 한국수의병리학회:학술대회논문집
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• 한국수의병리학회 2003년도 추계학술대회초록집
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• pp.49-49
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• 2003

PMWS is characterised by weight loss and dyspnea combined with pathological findings of interstitial pneumonia and generalized enlarged lymph nodes. Typical histological lesions include multifocal granulomatous pneumonia, and lymphocyte depletion and multinucleated giant cell formation in lymph nodes[1,2]. (omitted)

• 한국수의병리학회:학술대회논문집
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• 한국수의병리학회 2005년도 Proceedings of The 2nd Asian Society of Veterinary Pathology Symposium(Vol.2) and 2005 Annual Meeting of The Korean Society of Veterinary Pathology(Vol.9)
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• pp.72.1-73
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• 2005

• 대한수의학회지
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• 제41권3호
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• pp.367-371
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• 2001

Multiplex PCR and immunohistochemistry were used to detect and differentiate between porcine circovirus (PCV) type-I and the PCV associated with postweaning multisystemic wasting syndrome (PMWS). Unique DNA product to PCV type-II was confirmed the some organs including lymph nodes, tonsil and spleen from eight pigs in Jeju by multiplex PCR. In this study, the samples were tested by a multiplex PCR assay to determine the type of PCV in each case; all cases were PCV type-II positive. PCV type-II was identified not only in typical PMWS cases, but also in field cases submitted with various clinical histories, some of which were not suggestive of PMWS. Immunohistochemically PCV type-II antigen was detected in macrophage-like cells in the tonsil, liver, lymph nodes and spleen, while some hepatocytes and renal tubular epithelial cells were also positive to the virus. This study suggested that PCV type-II is one of the causative agents of PMWS as well as the major type of PCV in the affected pigs in Jeju.

• 한국동물위생학회지
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• 제34권1호
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• pp.13-18
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• 2011

The purpose of this study was to apply a nested-polymerase chain reaction (nPCR) assay to detect and differentiate PCV 2a and PCV 2b. The compared with nPCR and one-step PCR and nPCR showed more sensitive in the detection of PCV-2 from tissue and blood samples. The total of 52 tissue samples was collected from postweanning pigs from 2006 to 2010. All tissue samples showed positive for PCV-2 in one-step PCR and nPCR, followed by the nPCR in order to identify the genotypes of PCV-2. 2 samples (3.8%) showed positive for PCV 2a, and 35 samples were positive for PCV 2b (67.3%), 15 samples (28.9%) were positive the dual genotypes. In addition, 42 blood samples which were collected from the 5 different swine farms were compared figure out the detection rates of nPCR and one-step PCR. The PCV 2 was positive by one-step PCR in 21 samples (50.0%) and nPCR was positive in 37 samples (88.1%). The PCV 2 genotypes in blood samples and 32 samples (76.2%) were positive for PCV 2b and none were positive for PCV 2a, 5 samples (11.9%) were positive for dual genotypes. These results suggest that the nPCR is very efficient for genotyping blood samples and differentiating the genotypes of PCV-2 from field samples.

• Journal of Microbiology and Biotechnology
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• 제29권3호
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• pp.482-488
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• 2019

Porcine circovirus type 2 (PCV2) is the causative agent of postweaning multisystemic wasting syndrome (PMWS) in pigs. Replicase (Rep) proteins are considered essential for viral replication. Capsid (Cap) protein is the primary immunogenic protein that induces protective immunity. Little is known about comparison on the immunogenicity of PCV2 Rep and Cap fusion protein and Cap protein. In the present study, recombinant baculoviruses expressing the Rep-Cap fusion protein (Bac-Rep-Cap) and the Cap protein (Bac-Cap) of PCV2 were constructed and confirmed with western blot and indirect fluorescence assay. Immunogenicities of the two recombinant proteins were tested in mice. The titers of antibodies were determined with a PCV2-specific enzyme-linked immunosorbent assay (ELISA) and a serum neutralization assay. The $IFN-{\gamma}$ response of immunized mice was measured by ELISA. The mice immunized with the Bac-Rep-Cap and Bac-Cap successfully produced Cap-specific immunoreaction. The mice immunized with the Bac-Cap developed higher PCV2-specific neutralizing antibody titers than mice injected with the Bac-Rep-Cap. $IFN-{\gamma}$ in the Bac-Rep-Cap group was increased compared to those in the Bac-Cap group. Vaccination of mice with the Bac-Rep-Cap showed significantly decreased protective efficacy compared to the Bac-Cap. Our findings will indubitably not only lead to a better understanding of the immunogenicity of PCV2, but also improved vaccines.

• Journal of Veterinary Science
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• 제21권4호
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• pp.61.1-61.16
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• 2020

Background: Panax notoginseng saponins (PNS) are bioactive substances extracted from P. notoginseng that are widely used to treat cardiovascular and cerebrovascular diseases and interstitial diseases. PNS have the functions of scavenging free radicals, anti-inflammation, improving blood supply for tissue and so on. Objectives: The aim of this study was to investigate the effects of PNS on the oxidative stress of immune cells induced by porcine circovirus 2 (PCV2) infection in vitro and in vivo. Methods: Using an oxidative stress model of PCV2 infection in a porcine lung cell line (3D4/2 cells) and mice, the levels of nitric oxide (NO), reactive oxygen species (ROS), total glutathione (T-GSH), reduced glutathione (GSH), and oxidized glutathione (GSSG) and the activities of xanthine oxidase (XOD), myeloperoxidase (MPO) and inducible nitric oxide synthetase (iNOS) were determined to evaluate the regulatory effects of PNS on oxidative stress. Results: PNS treatment significantly reduced the levels of NO and ROS, the content of GSSG and the activities of XOD, MPO, and iNOS (p < 0.05), while significantly increasing GSH and the ratio of GSH/GSSG in infected 3D4/2 cells (p < 0.05).Similarly, in the in vivo study, PNS treatment significantly decreased the level of ROS in spleen lymphocytes of infected mice (p < 0.05), increased the levels of GSH and T-GSH (p < 0.05), significantly decreased the GSSG level (p < 0.05), and decreased the activities of XOD, MPO, and iNOS. Conclusions: PNS could regulate the oxidative stress of immune cells induced by PCV2 infection in vitro and in vivo.