• Title/Summary/Keyword: PRRSV

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Protection provided by a commercial modified-live porcine reproductive and respiratory syndrome virus (PRRSV) 1 vaccine (PRRSV1-MLV) against a Japanese PRRSV2 field strain

  • Joel Miranda;Salvador Romero;Lidia de Lucas;Fumitoshi Saito;Mar Fenech;Ivan Diaz
    • Journal of Veterinary Science
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    • v.24 no.5
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    • pp.54.1-54.13
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    • 2023
  • Background: Porcine reproductive and respiratory syndrome virus (PRRSV) vaccines do not provide full cross-protection, mainly due to the virus genetic variability. Despite this, vaccines based on modified-live PRRSV (PRRSV-MLV) reduce the disease impact. Objectives: To assess the efficacy of two commercial vaccines-one based on PRRSV1 (PRRSV1-MLV) and another on PRRSV2 (PRRSV2-MLV)-against a Japanese PRRSV2 field strain. Methods: Two groups of three-week-old piglets were vaccinated (G1: PRRSV1-MLV; G2: PRRSV2-MLV) and two were kept as non-vaccinated (INF and CTRL). One month later, G1, G2, and INF were challenged with a PRRSV2 field strain. Results: After the challenge, clinical signs were only observed in INF. Moreover, the highest rectal temperatures and values for the area under the curve (AUC) were observed in INF. Regarding viral detection, both AUC and the proportion of positive samples in blood were higher in INF. In G1, viremic animals never reached 100%. At necropsy (21 d after the challenge), differences for titers among groups were only found in tonsils (G1 < G2 and INF). One animal (belonging to G1) was negative in all tissues. Regarding humoral responses, G1 and G2 seroconverted after vaccination, as detected in the corresponding enzyme-linked immunosorbent assay. Specific neutralizing antibodies (NA) against PRRSV1-MLV were already detected at 14 d after vaccination in G1, showing a significant booster after the challenge, while PRRSV2-MLV NA were detected in G2 at the end of the experiment. Conclusions: Despite genetic differences, PRRSV1-MLV has been demonstrated to confer partial protection against a Japanese PRRSV2 strain, at least as good as PRRSV2-MLV.

Comparison of PRRSV and antibody detection in oral fluid and serum samples from different age categories of PRRSV endemic farms (PRRS 양성농장의 사육단계별 구강액과 혈액을 이용한 PRRSV와 항체 검출 비교)

  • Kim, Jung-Hee;Son, Jae Guk;Kim, Won-Il
    • Korean Journal of Veterinary Service
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    • v.43 no.3
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    • pp.173-179
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    • 2020
  • The objective of this study was to evaluate the usefulness of detection of PRRSV and PRRSV-specific antibodies in oral fluids for monitoring of PRRSV infection in endemic farms. The level of PRRSV and anti-PRRSV antibodies in serum and oral fluids was evaluated in five age groups of pigs (6, 9, 12, 16 weeks of age and gilts). The samples (25 serums and 5 oral fluids/per a farm) were collected from 5 different farms endemically infected by PRRSV. Both serum and oral fluid samples were tested for PRRSV by quantitative reverse-transcription polymerase chain reaction (qRT-PCR) and for anti-PRRSV antibodies by two commercial PRRSV ELISA kits. ELISA mean s/p ratios (2.98 vs 1.63) and positive rate (84.0% vs 68.8%) of the oral fluid samples showed significantly higher levels but had similar patterns to the seroprofile of the blood samples. The PRRSV positive rate of oral fluid and serum samples was 40.0% and 44.0% respectively. In conclusion, the use of oral fluids for PRRS monitoring in endemic farms is strongly recommended.

Expression of porcine reproductive and respiratory syndrome virus (PRRSV) ORF7 gene and monoclonal antibody production (돼지생식기호흡기증후군바이러스 ORF7 유전자 발현 및 단크론항체 생산)

  • Lee, Seung-Chul;Park, Ga-Hye;Lee, Kyeong-Won;Ryu, Min-Sang;Kang, Shien-Young
    • Korean Journal of Veterinary Service
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    • v.37 no.3
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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.

Serological and genetic characterization of the European strain of the porcine reproductive and respiratory syndrome virus isolated in Korea

  • Kim, June-Youp;Lee, Seung-Yoon;Sur, Jung-Hyang;Lyoo, Young S.
    • Korean Journal of Veterinary Research
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    • v.46 no.4
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    • pp.363-370
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    • 2006
  • Porcine reproductive and respiratory syndrome (PRRS) is an economically important disease of swine that occurs all over the swine industry worldwide. It was first observed in the Unite States in 1987 then in Europe in 1990. It has been described in Japan and in Korea in 1993. PRRS virus is divided into two distinct types, North American and European, genetically. Based on our limited knowledge there has been no report on the existence of European PRRSV. But according to the government's Korea Customs Service there has been many importations of breeding pigs from Europe. These seem to make an estimate that European PRRSV could be introduced in Korea by inflow of European breeding pigs. We first detected the European PRRSV could be introduced in Korean pig farms by using polymerase chain reaction (PCR). Further, it is also identified that there are not only North American PRRSV antibody but also a European PRRSV antibody. According to the genetical and serological experiment results, the presence of established North American PRRSV in Korea is due to the use of live vaccines made of North American PRRSV strain as well field virus infection, and the European PRRSV is possibly introduced from imported breeding stock.

Isolation and identification of porcine reproductive and respiratory syndrome virus from serum samples collected from swine farms (돼지 농장으로부터 수집한 혈청가검물에서 돼지생식기 호흡기증 바이러스의 분리 및 동정)

  • Kim, Hyun-Soo;Kong, Sin-Koog
    • Korean Journal of Veterinary Service
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    • v.22 no.4
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    • pp.363-370
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    • 1999
  • Isolation of PRRSV was attempted from 646 swine sera collected from swine farms. The MARC-145 cell, which is highly permissive to PRRSV, was used for virus isolation, propagation, IFA test, and VN test. Total 36 cytopathic viruses to MARC-145 cells were isolated. The virus isolates were identified as a PRRSV by the IFA test and VN test using the reference sera prepared by experimental infection of reference PRRSV CNV-1 into 30 day-old pig. In addition to serological conformation, ORF5 of genomic RNA of 6 selected cytopathic viruses were amplified by the RT-PCR. The resulting PCR products were examined by electrophoresis in 1.2% agarose gel. An appropriate bands of about 680bp including the flanking sequence of total 80bp were seen on agarose gel.

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Comparative evaluation of two commercial ELISA kits for detection of PRRS antibodies using sera collected from pigs in various stages of PRRSV infection (다양한 PRRSV 감염상태에 있는 돼지 혈청을 이용한 PRRS 항체 ELISA 키트들의 비교 평가)

  • Seo, Byoung-Joo;Kim, Hyoun-Il;Kim, Won-Il
    • Korean Journal of Veterinary Service
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    • v.37 no.3
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    • pp.151-156
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    • 2014
  • Porcine reproductive and respiratory syndrome virus (PRRSV) causes major economic losses to the Korean pig industry. ELISA tests using recombinant nucleocapsid protein of PRRSV have been most commonly used for PRRS diagnostics. In the current study, two commercial PRRSV ELISA kits (Bionote PRRSV Antibody ELISA and IDEXX 3XR PRRS Antibody ELISA) have been compared using sera collected from 19 swine farms in various stages of PRRSV infection confirmed by professional diagnostic centers. Thus 130 sera collected from 5 different farms with active PRRSV infection, 130 sera from 6 different farms with PRRS-stabilized status, and 140 sera from 8 different farms with PRRS-free status were evaluated to determine the correlation of test results between those ELISA kits. Both ELISA kits showed a good correlation [PRRSV-positive farms ($R^2$=0.6375) and stabilized farms ($R^2$=0.8928)] in sample-to-positive (S/P) ratio va lues. Among the 140 sera from negative farms, one sample was falsely positive by either of the ELISA kits. In conclusion, both of the ELISA kits showed a good correlation when applied on field samples collected from farms at various stages of PRRSV infection. Bionote ELISA or IDEXX ELISA gave a false positive result on 1 out of 140 negative samples so their specificity was calculated as 99.3%. Therefore, Bionote ELISA would be a good complementary and alternative method for IDEXX ELISA kit, and vice versa.

Characterization of Interaction Between Porcine Reproductive and Respiratory Syndrome Virus and Porcine Dendritic Cells

  • Park, Jie-Yeun;Kim, Hyun-Soo;Seo, Sang-Heui
    • Journal of Microbiology and Biotechnology
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    • v.18 no.10
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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.

Preliminary assessment of correlation between T-lymphocyte responses and control of porcine reproductive and respiratory syndrome virus (PRRSV) in piglets born after in-utero infection of a type 2 PRRSV

  • Cha, Sang-Ho;Bandaranayaka-Mudiyanselage, Carey;Bandaranayaka-Mudiyanselage, Chandima B.;Ajiththos, Dharani;Yoon, Kyoung-Jin;Gibson, Kathleen A.;Yu, Ji-Eun;Cho, In-Soo;Lee, Stephen S.;Chung, Chungwon J.
    • Korean Journal of Veterinary Research
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    • v.58 no.1
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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.

The correlation of porcine circovirus type 2 and porcine reproductive and respiratory syndrome virus in Salmonella Typhimurium enteritis (돼지 써코바이러스 2형 및 돼지 생식기 호흡기 증후군 바이러스가 Salmonella Typhimurium 장염에 미치는 영향)

  • Yang, Hyoung-Seok;Kim, Jae-Hoon
    • Korean Journal of Veterinary Service
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    • v.41 no.3
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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.

Enhanced expression of the structural protein of porcine reproductive and respiratory syndrome virus (PRRSV) by SUMO fusion

  • Koo, Hyun Na;Bae, Sung Min;Woo, Soo Dong
    • International Journal of Industrial Entomology
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    • v.32 no.2
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    • pp.90-97
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    • 2016
  • The major structural proteins of porcine reproductive and respiratory syndrome virus (PRRSV) are derived from ORFs 4, 5, and 6. They have been considered very important to arouse the humoral and cellular immune responses against PRRSV infection and proposed to be the excellent candidate proteins in the design of PRRS bioengineering vaccine. However, the PRRSV structural proteins are produced in low levels in the infected cells because it forms insoluble protein and possesses several transmembrane regions. To overcome this problem, we fused the ORF4, ORF5, and ORF6 with SUMO (small ubiquitin-related modifier). The resulting fusion protein SUMO-ORF4, -ORF5, and -ORF6 were highly expressed in Bm5 cells. The level of protein expression using the Bombyx mori larvae was higher than that using Bm5 cells. In addition, fusion to SUMOstar, which is not processed by native SUMO proteases, significantly enhanced protein expression levels compared to SUMO fusion. This study demonstrated that SUMO or SUMOstar, when fused with PRRSV structural proteins, was able to promote its soluble expression. This may be a better method to produce PRRSV structural proteins for vaccine development.