• Journal of Veterinary Science
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• 제21권5호
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• pp.78.1-78.15
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• 2020

Background: Enteritis is one of the most frequently reported symptoms in piglets infected with porcine circovirus type 2 (PCV2), but the immunopathogenesis has not been reported. Objectives: This study examined the effect of a PCV2 infection on the intestinal mucosal immune function through morphological observations and immune-related molecular detection. Methods: Morphological changes within the ileum of piglets during a PCV2 infection were observed. The expression of the related-molecules was analyzed using a gene chip. The immunocyte subsets were analyzed by flow cytometry. The secretory immunoglobulin A (SIgA) content was analyzed by enzyme-linked immunosorbent assay. Results: The PCV2 infection caused ileal villus damage, intestinal epithelial cells exfoliation, and an increase in lymphocytes in the lamina propria at 21 days post-infection. Differentially expressed genes occurred in the defense response, inflammatory response, and the complement and coagulation cascade reactions. Most of them were downregulated significantly at the induction site and upregulated at the effector site. The genes associated with SIgA production were downregulated significantly at the induction site. In contrast, the expression of the Toll-like receptor-related genes was upregulated significantly at the effector site. The frequencies of dendritic cells, B cells, and CD8⁺T cells were upregulated at the 2 sites. The SIgA content decreased significantly in the ileal mucosa. Conclusions: PCV2 infections can cause damage to the ileum that is associated with changes in immune-related gene expression, immune-related cell subsets, and SIgA production. These findings elucidated the molecular changes in the ileum after a PCV2 infection from the perspective of intestinal mucosal immunity, which provides insights into a further study for PCV2-induced enteritis.

• 대한수의학회지
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• 제48권3호
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• pp.267-274
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• 2008

This study was to evaluate the efficacy of single dose Mycoplasma hyopneumoniae (M. hyo)-vaccination in the swine farms which had different serological patterns of porcine reproductive and respiratory syndrome virus (PRRSV) and porcine circovirus type 2 (PCV2). A minimum of 240 pigs from each farm was applied, allocating M. hyo vaccinated and control groups. The PRRSV and PCV2 infections were analyzed by serological method (commercial ELISA kit). After administrating pigs a single dose of M. hyo vaccine or control saline at 3 weeks of age, serum antibodies to M. hyo, PRRSV and PCV2 were monitored at 4, 10, 16 and 22 weeks of age. Mortality, weight changes, feed conversion ratio (FCR) and lung score were also evaluated. A single-dose vaccination of M. hyo bacterin was efficacious to reduce mycoplasmal lung lesions and induce good humoral immune response. However, FCR was improved only in one of the three farms where showed seronegative status to both PRRSV and PCV2 in the period from 4 to 16 weeks of age. These results might imply that M. hyo vaccine alone could not overcome the PRRSV and PCV2 infection-associated wasting in the field condition. Therefore, the control of PRRSV and PCV2 should be considered to obtain the better effects of M. hyo vaccination.

• International Journal of Automotive Technology
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• 제8권2호
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• pp.219-224
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• 2007

Recently, atmospheric contaminations has become worse due to the increased number of automobile. The PCV (Positive Crankcase Ventilation) valve acts as a flow control to allow re-combustion of blow-by gas by having it flow from a crankcase to an inlet manifold suction tube. Also, during the fabrication of the PCV valve, micro cracks may occur in the valve body and be extended under operation. The excessive stress distribution and crack initiation on the PCV valve body would bring an unstable blow-by gas flow rate control and would cause valve failure. The purpose of this study is to examine the crack affects on the stress and strain variations on the PCV valve according to the inlet and outlet manifold under differential pressures. From the results, we can explain the behavior of the crack extension for a safe condition of PCV valve.

• Clinical and Experimental Pediatrics
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• 제57권2호
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• pp.55-66
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• 2014

The 7-valent pneumococcal protein conjugate vaccine (PCV7) has been shown to be highly efficacious against invasive pneumococcal diseases and effective against pneumonia and in reducing otitis media. The introduction of PCV7 has resulted in major changes in the epidemiology of pneumococcal diseases. However, pneumococcal vaccines induce serotype-specific immunity, and a relative increase in non-vaccine serotypes has been reported following the widespread use of PCV7, leading to a need for extended serotype coverage for protection. PCV10 and PCV13 have been licensed on the basis of noninferiority of immunogenicity compared to a licensed conjugate vaccine. In this article, we aimed to review important data regarding the efficacy and effectiveness of the extended-coverage PCVs published or reported thus far and to discuss future implications for pneumococcal vaccines in Korea. After the introduction of PCV10 and PCV13, within a short period of time, evidence of protection conferred by these vaccines against invasive and mucosal infections caused by most of the serotypes included in the vaccines is accumulating. The choice of vaccine should be based on the changes in the dynamics of pneumococcal serotype distribution and diseases in the region where the vaccines are to be used. Continuous surveillance is essential for the appropriate use of pneumococcal vaccines and evaluation of the impact of PCVs on pneumococcal diseases.

• 대한수의학회지
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• 제53권4호
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• pp.245-251
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• 2013

Porcine circovirus type 2 (PCV2) and porcine reproductive and respiratory syndrome virus (PRRSV) have been suspected to have immunosuppressive effects on pigs. To investigate the correlation between these virus infection and the lesions of lymph nodes including sub-mandibular and inguinal lymph node, 44 pigs (PCV2 single, n = 14; PRRSV single, n = 10; PCV2/PRRSV, n = 14; negative control, n = 6) were examined by histopathology and immunohistochemistry. Histopathologically, granulomatous lymphadenitis characterized by lymphoid depletion with histiocytic cells infiltration was observed in PCV-2 single and PCV-2/PRRSV group. Immunohistochemically, there were significant reduction of B and T lymphocytes in lymph nodes of these groups, while the number of macrophages was increased. In only PRRSV infected group, germinal center hypertrophy and lymphoid necrosis were observed. Immunohistochemically, the number of CD3+ T lymphocytes was slightly increased. Severe lymphocytic depletion in PCV-2 infection-related lymph nodes might be associated with producing immunocompromised state in pig. Comparing with PCV-2 infected group, PRRSV produced minor effects on the changes in immune cell population in the lymph nodes of pigs. PRRSV may increase susceptibility of the disease in pigs by disruption of the first defense lines in target organs, such as the alveolar macrophages in lungs.

• 한국동물위생학회지
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• 제32권4호
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• pp.299-306
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• 2009

Assay for the detection and quantification of porcine circovirus type 2 (PCV 2) with the real-time PCR were developed. TaqMan probe real-time using a set of primer/probe was developed for detection of PCV 2. In this study we applied real-time PCR assay to 320 samples, collected from pig farms. In 151 of 320 samples, PCV 2 DNA was detected by conventional PCR assay. All samples positive for PCV 2 DNA in conventional PCR assay were also positive in Real-time PCR assay, but 69 of 169 samples that tested negative for PCV 2 DNA in conventional assay were tested positive in TaqMan probe real-time PCR assay. The test of TaqMan probe real-time PCR resulted in detection and quantification limits of 101 copies per sample. TaqMan probe real-time PCR assay increased the number of samples in which PCV 2 was detected by 21%. TaqMan probe real-time PCR assay is very efficient method in contrast to the conventinal PCR, becoming increasingly important method for gene analysis.

• 미생물학회지
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• 제17권1호
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• pp.42-48
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• 1979

Pemicillum chrysogenum의 건전균(PC)과 바이러스감염균(PCV)을 사용하여 cellulase의 존재여부와 그 활성 정도를 알아보기 위해 밀기울에 배양하여 효소액으로 만들어 균의 생장에 따른 배양액의 최적 pH와 최적 배양일 및 Na-CMC 기질액을 이용하여 효소액의 활성에 미치는 최적 pH, 온도, 및 효소농도를 알아보고자 본 실험에 착수하여 다음과 같은 결과를 얻었기에 이에 보고하는 바이다. 1) PC외 PCV균의 생장에 따른 배양액의 최적 pH는 균주 접종전 배지와 작은 pH6.4로 나타났다. 2) 최적 배양일은 최적 pH를 나타낸 배양6일이 가장 높은 활성을 나타냈고, PCV는 PC의 50%의 활성이었다. 3) PC균 배양 효소액이 기질과 반응시 효소활성이 가장 높은 최적 pH는 pH5.0으로 나타났고, PCV 균 배양 효소액에서는 pH 6.0으로 나타났다. 4) PC와 PCV균 배양효소액 모두 기질과 반응시 효소 활성이 가장 높은 최적 온도는 $50^{\circ}C$로나타났다. 이상의 결과에서 cellulase의 활성도는 PC건전균이 PCV감입균보다 높은 활성을 나타낸 것을 알 수 있었다.

• 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.

• 한국동물위생학회지
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• 제45권1호
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• pp.63-69
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• 2022

Proliferative and necrotizing pneumonia (PNP) is a form of interstitial pneumonia that occurs in post-weaning pigs. In this study, we investigated the presence of swine influenza virus (SIV), porcine reproductive and respiratory syndrome virus (PRRSV), porcine circovirus type 2 (PCV2) and Aujeszky's disease virus (ADV) in PNP lesions in Jeju pigs. Based on the histopathologic criteria for PNP, a total of 50 cases were selected in Jeju pigs between 2008 and 2010. Coupled with histopathological examinations, the presence of ADV and SIV by polymerase chain reaction (PCR) and reverse transcription PCR (RT-PCR) and PRRSV and PCV2 by immunohistochemical (IHC) methods were investigated. Based on the PCR and RT-PCR methods, ADV and SIV nucleic acids were not detected in all cases. According to IHC, PRRSV was detected in 38 of the 50 cases examined (76%) and PCV2 in 25 cases (50%). PRRSV or PCV2 were detected in 19 (38%) or 6 (12%) cases, respectively. Both PRRSV and PCV2 were identified in other 19 cases (38%). Antigens of PRRSV and PCV2 were commonly observed in the cytoplasm of macrophages and clusters of necrotic cells in alveolar cavities. The results of the present study demonstrate that PRRSV is predominantly associated with PNP in Jeju pigs. Co-infection with PRRSV and PCV2 may enhance the severity of PNP lesions in affected pigs.

• 동력기계공학회지
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• 제10권2호
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• pp.68-74
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• 2006

In the development of new automobiles, the efforts to reduce environmental problems like air pollution have been risen. Blowby gas consists of about $20{\sim}35%$ of total amount of Hydrocarbon (HC), one of dangerous pollutants issuing from automobiles. A PCV valve is a very small component in an automotive engine but it is a very important part. Because that a PCV valve is used to control blowby gas and to recirculate it into a manifold automatically. Although it has very simple operating principle, designing a PCV valve is so difficult due to interaction between fluid and solid. In this study, our purpose is to develop a design program for a PCV valve and to verify its efficiency. Both Bernoulli equation and 4th order Runge-Kutta method were adopted to predict spool displacements and flow patterns. Comparing with experiments, it was found that both spool diameters and displacements were predicted well, however, flow rates showed a little differences because of the assumption of non viscous flow.