Reproductive Respiratory Syndrome Virus Research Articles

CXCL-10/CXCR3 in macrophages regulates tissue repair by controlling the expression of Arg1, VEGFa and TNFα.

Macrophages have been reported to participate in inflammation, tissue homeostasis and tissue repair. The detailed mechanism of macrophage-mediated tissue repair is not clear. CXCL-10, secreted by monocytes, endothelial cells and fibroblasts, mediates immune response and angiogenesis by binding to CXCR3. In this study, the expression of CXCL-10 and CXCR3 in porcine lung injury induced by porcine reproductive and respiratory syndrome virus (PRRSV) infection was firstly examined. The results showed that the expression of both CXCL-10 and CXCR3 increased in the infected pig lungs. In addition, the increased expression of CXCL-10 and CXCR3 in macrophage treated by poly (I:C) was also observed, suggesting the autocrine system existed in macrophages. Furthermore, CXCL-10 treatment induced upregulation of Arg1 and VEGFa, and downregulation of TNFα in macrophage, and CXCR3 antagonist AMG487 treatment presented the contrary effects on the expression of Arg1, VEGFa, and TNFα. CXCL- 10-stimulated effects were dependent on PI3K/Akt signaling pathway. Wound-healing assay showed that CXCL-10 treatment macrophage conditioned medium promoted the healing process of endothelial cells. Our results suggested that CXCL-10/CXCR3 in macrophage may mediate tissue repair by regulating the macrophage expression of Arg1, VEGFa and TNFα. Modulation of CXCL-10/CXCR3 axis in macrophage may be a potential therapeutic strategy for tissue injury and repair.

Correction: Developing a Triple Transgenic Cell Line for High-Efficiency Porcine Reproductive and Respiratory Syndrome Virus Infection.

[This corrects the article DOI: 10.1371/journal.pone.0154238.].

112 Genetic parameters and genomic regions associated with piglet response to vaccination for porcine reproductive and respiratory syndrome (PRRS) virus and co-infection with PRRS virus and porcine circovirus type 2b (PCV2b)

Citation: Dunkelberger, J. R., Serao, N. V. L., Kerrigan, M. A., Lunney, J. K., Rowland, R. R. R., & Dekkers, J. C. M. (2016). Genetic parameters and genomic regions associated with piglet response to vaccination for porcine reproductive and respiratory syndrome (PRRS) virus and co-infection with PRRS virus and porcine circovirus type 2b (PCV2b). Journal of Animal Science, 94, 52-53. doi:10.2527/msasas2016-112

Evidence of porcine reproductive and respiratory syndrome virus antibodies in commercial pig husbandry in Nigeria: a preliminary study

Livestock production is one of the main economic resources of developing countries. In Nigeria, pig farming contributes significantly to the livestock sub-sector and accounts for about 30% of total pig production in Africa. Many infectious diseases never described before in this region may be responsible for production and productivity losses. A preliminary investigation to detect antibodies to porcine reproductive and respiratory syndrome (PRRS), an emerging disease of pigs, in a commercial pig husbandry complex with history of respiratory and reproductive disorders was conducted in Lagos, Nigeria. Two hundred and twenty-one sera randomly collected over six months from slaughtered pigs were analysed for PRRS virus antibodies by enzyme-linked immunosorbent assay (ELISA) according to the protocol described by the Office International des Epizooties. Only three specimens from breeding boars (1.4%) out of the total samples analysed were positive for antibodies to the virus. Though the sero-prevalence is low, it is yet an evidence of infection with a virus not previously reported in Nigeria and an indication of its possible contribution to the clinical syndrome observed in the piggery complex. This report, to our knowledge, represents the first serologic evidence of porcine reproductive and respiratory syndrome in Nigeria. It underscores the need for further serological and virological investigations to establish the actual burden of the disease and inform the institution of appropriate control measures to forestall associated production losses in the pig industry.Keywords: Porcine reproduction, Respiratory syndrome, Antibodies, Pigs, ELISA

Recombinant chimeric vaccine composed of PRRSV antigens and truncated Pseudomonas exotoxin A (PE-K13)

A Pseudomonas exotoxin (PE-KDEL)-based chimeric subunit vaccine system was recently developed using a reverse vaccinology technique. In this study, the plasmids containing PE-PRRS chimeric subunits were constructed that composed of porcine reproductive and respiratory syndrome virus (PRRSV) antigen moieties, a ligand moiety and a Pseudomonas exotoxin A deleted domain III (PE (ΔIII)), and a carboxyl terminal moiety that includes a polypeptide with amino acid sequence KDEL (K3). The PE-PRRS combination vaccine can effectively induce not only PRRSV-specific INF-γ cellular immunity but also a slow-reacting and complement-requiring type serum neutralizing antibody in pigs. In a specific pathogen free (SPF) pig challenge model, body temperature (colonic temperature), occurrence of PRRSV viremia, nasal excretions, gross and histopathological appearances of pneumonia, and serum antibody activity (IFA and SN) titers significantly differed between the immunized group and the control group. The survey showed that a 0.3mg/dose PE-PRRS vaccine formula conferred protection against PRRSV. A field trial of PE-PRRS vaccine was performed to study the immune response of pregnant sows after vaccination in a PRRSV persist farm. The RT-PCR analysis of viremia and serological titers showed that the PE-PRRS vaccine not only increased sow reproductive performance and evoked its immune response to PRRS viremia, it also activated maternal immune protections to prevent piglets from inflicting viremia. In conclusion, we developed a novel and effective PRRS cytotoxic T-cells (CTLs)-based vaccine containing Pseudomonas exotoxin (PE-KDEL) carrier in combination with PRRSV conserved epitopes against PRRS virus.

Porcine reproductive and respiratory syndrome virus detection in Thailand during 2005–2010 in relation to clinical problems, pig types, regions, and seasons

The objectives of the present study were to determine the prevalence of porcine reproductive and respiratory syndrome virus (PRRSV) in Thailand between 2005 and 2010. The study was conducted by retrospectively investigating the detection of PRRSV from different pig types including boars, sows, piglets, nursery pigs, and fattening pigs from six regions of Thailand, i.e., the northern, eastern, northeastern, central, western, and southern parts. The data were obtained from cases submitted to the Chulalongkorn University Veterinary Diagnostic Laboratory for PRRSV detection between 2005 and 2010. Frequency analyses and generalized linear models were used to evaluate the prevalence of PRRSV in relation to various factors. In total, 2,273 tissues (n = 636), semen (n = 210) and serum (n = 1,427) samples were included. PRRSV was detected in 32.6% (740/2,273) of the pigs. The virus was found in 43.1%, 15.7%, and 30.3% in the tissues, semen, and serum samples, respectively (P < 0.001). The prevalence of PRRSV was highest in 2005 (43.6%) and lowest in 2009 (23.6%) (P < 0.001). The prevalence of PRRSV was highest in nursery pigs (43.7%) and lowest in boars (15.4%) (P < 0.001). The prevalence of PRRSV in the hot season (34.9%) was higher than that found in the cool season (28.1%, P = 0.018) but did not differ significantly compared to rainy season (34.0%, P = 0.486). The strain of PRRSV isolated in the present study was genotype 2 (54.5%), genotype 1 (31.0%), and mixed genotypes (14.5%). It can be concluded that PRRSV was detected in the tissue samples more frequently than the semen and serum samples. The prevalence of PRRSV was high in the nursery pigs. A high prevalence of PRRSV was found in the hot season, indicating that climatic factors may also contribute to the prevalence of PRRSV in Thailand. Of all the PRRSV detected, 31.0%, 54.5%, and 14.5% belonged to genotype 1, genotype 2, and mixed genotypes, respectively.

Genetic diversity analysis of the ORF5 gene in porcine reproductive and respiratory syndrome virus samples from South China

To understand the genetic diversity of porcine reproductive and respiratory syndrome virus (PRRSV) in South China, we collected 231 clinical samples from pigs with suspected PRRSV infection in Guangdong between 2007 and 2009. We found that 74 of 231 samples were positive by RT-PCR. The PCR products of the ORF5 gene of 35 isolates from different farms were sequenced and their DNA sequences were compared to 23 other PRRSV isolates in the GenBank. We found that the nucleotide similarity among all South China isolates ranged from 87.6% to 100%, and all belonged to the North American genotype. Most of them were classified into subgenotype I, but the rest mapped to subgenotypes III, V or VI. Those in subgenotypes I and III were found to be highly variable in the primary neutralising epitope (PNE) with a specific amino acid mutation (F39/L39→I39), and a few isolates in subgenotypes I and III isolates also had a mutation at L41 (L41→S41). PRRSV isolates in subgenotypes III, V and VI had less potential glycosylation sites than those in subgenotype I. Our data contribute to the understanding of molecular variation of PRRSV in South China.

New insights into RNA packaging in porcine reproductive and respiratory syndrome virus

While identifying whether the smallest packaged heteroclite subgenomic RNA (S9) of porcine reproductive and respiratory syndrome virus (PRRSV) contains a packaging signal, we found that S9 was capable of binding to the basic amino acid-rich domain (synthetic peptide of aa 34-53) of the packaging protein (N). In addition, by using truncations at the 5' and 3' ends of S9, a minimal binding region of 35 nt was found to be essential for binding to both the synthetic peptide and to the full-length N protein. Furthermore, by using cell-culture experiments, we found that S9 was capable of packaging non-viral RNA sequence into PRRSV particles and that the 35 nt region was essential for this activity. Taken together, our data suggest that this 35 nt region might be an important element for packaging PRRSV genomic RNA into virus particles.

Isolation and Genome Characterization of Porcine Reproductive and Respiratory Syndrome Virus in P. R. China

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Biochemical and molecular analysis of structural proteins of porcine reproductive and respiratory syndrome virus

Biochemical and molecular analysis of structural proteins of porcine reproductive and respiratory syndrome virus

Seroprevalence of antibody to porcine reproductive and respiratory syndrome virus using enzyme-linked immunosorbent assay in selected herds in Korea.

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