• Journal of Microbiology and Biotechnology
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• 제18권10호
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• pp.1709-1716
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• 2008

The porcine reproductive and respiratory syndrome Virus (PRRSV) is an infectious disease that causes abortions and respiratory disorders in swine. In this study, the interaction between PRRSV and porcine dendritic cells generated from $CD14^{+}$ monocytes in the presence of GM-CSF and IL-4 was examined. As a result, it was shown that immature and mature dendritic cells can be productively infected with PRRSV. When the expression of surface MHC molecules on infected dendritic cells was determined, MHC classes I and II were found to be downregulated when compared with un infected dendritic cells. With the exception of the IL-4 and IFN-$\gamma$ cytokines, the induction of the IL-10, IL-12, and TNF-$\alpha$ cytokines all increased in dendritic cells infected with PRRSV. A mixed lymphocyte reaction showed that peripheral blood mononuclear cells cocultured with PRRSV-infected dendritic cells were less stimulated than peripheral blood mononuclear cells cocultured with dendritic cells treated with PBS, LPS, or UV-inactivated PRRSV. Therefore, these results suggest that PRRSV would appear to modulate the immune stimulatory function of porcine dendritic cells.

• 한국동물위생학회지
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• 제37권3호
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• pp.143-150
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• 2014

Porcine reproductive and respiratory syndrome virus (PRRSV) is the etiological agent of PRRS characterized by reproductive losses in sows and respiratory disorders in piglets. The PRRSV is a small enveloped virus containing a positive-sense, single-stranded RNA genome and divided into two genotype, type 1 (European) and type 2 (North American), respectively, by nucleotide identity. In this study, ORF7 gene of the type 1 and type 2 PRRSV was cloned and expressed in Baculovirus expression system. Also, monoclonal antibodies (MAbs) against ORF7 were produced and characterized. The expressed ORF7 proteins in the recombinant virus were confirmed by indirect fluorescence antibody (IFA) test using His6 and PRRSV-specific antiserum. A total of eight MAbs were produced and characterized. One (3G12) MAb was type 1 PRRSV ORF7-specific and two (6B10 and 16H8) were type 2 PRRSV ORF7-specific. Other five (1A1, 2A4, 4B4, 12C4 and 13F11) MAbs reacted with both type 1 and type 2 PRRSV. Some PRRSV ORF7-specific MAbs recognized the porcine tissues infected with PRRSV by IFA or immunohistochemistry (IHC) assay. From this experiment, it was confirmed that MAbs produced in this study were PRRSV ORF7-specific and could be used as reliable reagents for type 1/type 2 PRRSV detection.

• 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.

• 대한수의학회지
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• 제44권4호
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• pp.561-569
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• 2004

To detect viral agents and isolate porcine circovirus 2 (PCV2), 60 samples of lung and lymph node were collected from 5 to 12 week-old pigs that had showed clinical signs of postweaning multisystemic wasting syndrome (PMWS). Polymerase chain reactions (PCRs) were conducted to identify the viral pathogens including PCV1, PCV2, porcine parvovirus (PPV) and porcine reproductive and respiratory syndrome virus (PRRSV) that have been considered to be the causal agents of PMWS. Among 60 samples, PCV 2 was detected from 57 samples but no PCV 1 was detected. PRRSV and/or PPV were also detected from 27 (47.4%) samples and 1 (1.8%) sample of these 57 PCV 2-positive samples, respectively. Tissue homogenates were inoculated onto PCV-free PK-15 cell monolayers. Seven isolates were confirmed as PCV 2 by multiplex PCR, indirect immunofluorescence assay, and transmissible electron microscopy. These date suggest that PRRSV is a major cofactors causing PMWS in pigs that were infected with PCV2 in Korea.

• 한국수의병리학회지
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• 제1권2호
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• pp.125-134
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• 1997

Porcine Reproductive and Respiratory Syndrome Virus infection (PRRSV) was confirmed by serology histopathology immunohistochemistry and bacteriologic examination in young pigs. Four suckling and six weaned piglets submitted from three different farms showed coughing sneezing labored rapid abdominal respiration lethargy and anorexia. Grossly apical and cardiac lung lobes appeared mottled with pale to dark tan discoloration. Submandibular and bronchial lymph nodes were tan and enlarged. All piglets were seropositive for PRRSV antibodies by the indirect immunofluorescent antibody(IFA) test. Microscopically lung lesions were characterized by hyperplasia and hypertrophy of type 2 pneumocytes infiltration of mononuclear cells in alveolar intersitium accumulation of necrotic debris in alveolar spaces accompanied by proliferation of alveolar multinucleated syncytial cells. Using immunohistochemical technique PRRSV antigens were demonstrated in alveolar macrophages and type 2 pneumocytes in histologic lung tissue sections. Also PRRSV antigens were detected in brain lymph nodes spleen and heart. Additionally piglets showed nonsuppurative meningoencephalitis mandibular necrotic lymphadenopathy splenic atrophy and myocardial necrosis.

• 한국동물위생학회지
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• 제41권3호
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• pp.133-139
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• 2018

Porcine circovirus type 2 (PCV2) and porcine reproductive and respiratory syndrome virus (PRRSV) are known as significant immunosuppressive viruses in pigs. In this study, we investigated the correlation of PCV2 and PRRSV in enteric lesions of porcine salmonellosis. A total of 64 cases were classified into four pig groups as group A (24 cases, S. Typhimurium), group B (11 cases, S. Typhimurium+PCV2), group C (16 cases, S. Typhimurium+PRRSV) and group D (13 cases, S. Typhimurium+PCV2+PRRSV). Comparing with group A, ulcerative enteritis in large intestine was little more prevalent in the PCV2 infected pigs in group B and D. And lymphoid depletion in gut-associated lymphatic tissue (GALT) of large intestine was also detected in PCV2 positive group B (36.4%) and D (30.8%). According to the results of immunohistochemistry (IHC), PCV2 antigens (83.3%) were more prevalently distributed in the intestinal lesions of porcine salmonellosis than PRRSV antigens (10.3%). PCV2 were also detected in the lymphoid depleted GALT of the large intestine from 7 of the 8 pigs (87.5%), but PRRSV were not found in all cases. It may explain that PCV2 can play a certain immunological role to enhance secondary bacterial infection in porcine alimentary tracts.

• Journal of Veterinary Science
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• 제22권6호
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• pp.87.1-87.12
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• 2021

Background: African swine fever virus (ASFV), classical swine fever virus (CSFV), and porcine reproductive and respiratory syndrome virus (PRRSV) are still prevalent in many regions of China. Co-infections make it difficult to distinguish their clinical symptoms and pathological changes. Therefore, a rapid and specific method is needed for the differential detection of these pathogens. Objectives: The aim of this study was to develop a multiplex real-time quantitative reverse transcription polymerase chain reaction (multiplex qRT-PCR) for the simultaneous differential detection of ASFV, CSFV, and PRRSV. Methods: Three pairs of primers and TaqMan probes targeting the ASFV p72 gene, CSFV 5' untranslated region, and PRRSV ORF7 gene were designed. After optimizing the reaction conditions, including the annealing temperature, primer concentration, and probe concentration, multiplex qRT-PCR for simultaneous and differential detection of ASFV, CSFV, and PRRSV was developed. Subsequently, 1,143 clinical samples were detected to verify the practicality of the assay. Results: The multiplex qRT-PCR assay could specifically and simultaneously detect the ASFV, CSFV, and PRRSV with a detection limit of 1.78 × 10⁰ copies for the ASFV, CSFV, and PRRSV, but could not amplify the other major porcine viruses, such as pseudorabies virus, porcine circovirus type 1 (PCV1), PCV2, PCV3, foot-and-mouth disease virus, porcine parvovirus, atypical porcine pestivirus, and Senecavirus A. The assay had good repeatability with coefficients of variation of intra- and inter-assay of less than 1.2%. Finally, the assay was used to detect 1,143 clinical samples to evaluate its practicality in the field. The positive rates of ASFV, CSFV, and PRRSV were 25.63%, 9.36%, and 17.50%, respectively. The co-infection rates of ASFV+CSFV, ASFV+PRRSV, CSFV+PRRSV, and ASFV+CSFV+PRRSV were 2.45%, 2.36%, 1.57%, and 0.17%, respectively. Conclusions: The multiplex qRT-PCR developed in this study could provide a rapid, sensitive, specific diagnostic tool for the simultaneous and differential detection of ASFV, CSFV, and PRRSV.

• 대한수의학회지
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• 제58권1호
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• pp.9-16
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• 2018

A preliminary study into the protective mechanisms of adaptive immunity against porcine reproductive and respiratory syndrome virus (PRRSV) in piglets (n = 9) born to a gilt challenged intranasally with a type-2 PRRSV. Immune parameters (neutralizing antibodies, $CD3^+CD4^+$, $CD3^+CD8^+$, $CD3^+CD4^+CD8^+$ T-lymphocytes, and PRRSV-specific interferon $(IFN)-{\gamma}$ secreting T-lymphocytes) were compared with infection parameters (macro- and microscopic lung lesion, and PRRSV-infected porcine alveolar macrophages ($CD172{\alpha}^+PRRSV-N^+\;PAM$) as well as with plasma and lymphoid tissue viral loads. Percentages of three T-lymphocyte phenotypes in 14-days post-birth (dpb) peripheral blood mononuclear cell (PBMC) had significant negative correlations with percentages of $CD172{\alpha}^+PRRSV-N^+\;PAM$ (p < 0.05) as well as with macroscopic lung lesion (p < 0.01). Plasma and tissue viral loads had significant (p < 0.05) negative correlations with $CD3^+CD4^+CD8^+$ T-lymphocyte percentage in PBMC. Frequencies of $CD3^+CD8^+$ and $CD3^+CD4^+$ T-lymphocytes in 14-dpb PBMC had significant negative correlations with of lymph node (p = 0.04) and lung (p = 0.002) viral loads. $IFN-{\gamma}$-secreting T-lymphocytes frequency had a significant negative correlation with gross lung lesion severity (p = 0.002). However, neutralizing antibody titers had no significant negative correlation (p > 0.1) with infection parameters. The results indicate that T-lymphocytes contribute to controlling PRRSV replication in young piglets born after in-utero infection.

• 대한수의학회지
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• 제58권3호
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• pp.137-141
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• 2018

The efficacy of the CA-2-MP120 vaccine, a cell culture-attenuated strain of virulent porcine reproductive and respiratory syndrome virus (PRRSV), was assessed in pigs. Despite the persistence of viremia in all vaccinated animals during the immunization period, the virus was not detected in vaccinated pigs following challenge. Furthermore, no pigs in the vaccinated group shed PRRSV nasally, orally or rectally throughout the experiment. Moreover, histopathological lung and lymph node lesions in the immunized group were much milder than those in the unimmunized and challenged group. These results indicated that CA-2-MP120 can provide effective protection against virulent wild-type PRRSV-2.

• 한국동물위생학회지
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• 제39권2호
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• pp.117-124
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• 2016

In this study, the virucidal efficacy of a fumigant containing 20% ortho-phenylphenol against classical swine fever virus (CSFV) and porcine reproductive and respiratory syndrome virus (PRRSV) was examined. After each carrier deposited with CSFV and PRRSV suspensions was exposed to the fumigant in a $25-m^3$ test room for 15 h, all carriers were neutralized and diluted, and each diluted suspension was inoculated into each proper cell line. After incubation, CSFV and PRRSV viability in each cell line was examined and 50% tissue culture infectious dose $(TCID_{50})/mL$ was calculated. In the results, the concentration of viable virus in all of pathogen control-carriers was more than $2{\times}10^5TCID_{50}/mL$, and there were no cytotoxicity in all of toxicity control-carriers. In addition, the fumigant inactivated ${\geq}4.8{\log}_{10}(TCID_{50}/mL)$ of both CSFV and PRRSV. These findings will be useful for preventing the spread of CSFV and PRRSV infection.