Somatostatin (SS) is a hormone that inhibits the secretion of growth hormone. Immunization against SS can promote thegrowth of animals. This paper described the effects of DNA immunization on the growth and antibody r...Somatostatin (SS) is a hormone that inhibits the secretion of growth hormone. Immunization against SS can promote thegrowth of animals. This paper described the effects of DNA immunization on the growth and antibody response in miceand pigs immunized with a plasmid DNA encoding SS fused with GP5 of porcine reproductive and respiratory syndromevirus (PRRSV). A fragment of 180 bp encoding partial SS gene was amplified by PCR from the genomic DNA of peripheralblood mononuclear cells of pigs, and cloned as a fusion gene with PRRSV GP5 in plasmid pISGRTK3. Three times ofimmunization with the resulting plasmid pISG-SS/GP5 induced anti-GP5 antibodies in BALB/c mice and pigs, as demonstratedby GP5-specific ELISA and immunoblotting. Compared with pigs immunized with empty vector pISGRTK3, the growthperformance of pigs immunized with pISG-SS/GP5 was increased by 11.1% on the 13th week after the last vaccination. Theresults indicated the plasmid DNA encoding SS and PRRSV GP5 fusion gene elicited anti-GP5 antibodies and improvedthe growth performance of immunized pigs.展开更多
Porcine reproductive and respiratory syndrome virus(PRRSV) infection is the leading cause of economic casualty in swine industry worldwide. The virus can cause reproductive failure, respiratory disease, and growth ret...Porcine reproductive and respiratory syndrome virus(PRRSV) infection is the leading cause of economic casualty in swine industry worldwide. The virus can cause reproductive failure, respiratory disease, and growth retardation in the pigs. This review deals with current status of commercial PRRS vaccines presently used to control PRRS. The review focuses on the immunogenicity, protective efficacy and safety aspects of the vaccines. Commercial PRRS modified-live virus(MLV) vaccine elicits delayed humoral and cell-mediated immune responses following vaccination. The vaccine confers late but effective protection against genetically homologous PRRSV, and partial protection against genetically heterologous virus. The MLV vaccine is of concern for its safety as the vaccine virus can revert to virulence and cause diseases. PRRS killed virus(KV) vaccine, on the other hand, is safe but confers limited protection against either homologous or heterologous virus. The KV vaccine yet helps reduce disease severity when administered to the PRRSV-infected pigs. Although efforts have been made to improve the immunogenicity, ef-ficacy and safety of PRRS vaccines, a better vaccine is still needed in order to protect against PRRSV.展开更多
A multiplex reverse transcriptase-polymerase chain reaction(multiplex RT-PCR) assay was developed and subsequently evaluated for its efficacy in the detection of multiple viral infections simultaneously,in swine.Speci...A multiplex reverse transcriptase-polymerase chain reaction(multiplex RT-PCR) assay was developed and subsequently evaluated for its efficacy in the detection of multiple viral infections simultaneously,in swine.Specific primers for each of the 3 RNA viruses,North American genotype porcine reproductive and respiratory syndrome virus,Japanese encephalitis virus,and swine influenza virus,were used in the testing procedure.The assay was shown to be highly sensitive because it could detect as little as 10-5 ng of each of the respective amplicons in a single sample containing a composite of all 3 viruses.The assay was also effective in detecting one or more of the same viruses in various combinations in specimens,including lymph nodes,lungs,spleens,and tonsils,collected from clinically ill pigs and in spleen specimens collected from aborted pig fetuses.The results from the multiplex RT-PCR were confirmed by virus isolation.The relative efficiency(compared to the efficiency of separate assays for each virus) and apparent sensitivity of the multiplex RT-PCR method show that this method has potential for application in routine molecular diagnostic procedures.展开更多
Since May 2006,a highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV) variant characterized by 30 amino acids deletion within its NSP2-coding region emerged and caused extensive economic lo...Since May 2006,a highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV) variant characterized by 30 amino acids deletion within its NSP2-coding region emerged and caused extensive economic losses to China's pig industry.To investigate the in vivo pathogenicity and immune responses of the newly emerging PRRSV,3 groups of 60-d-old conventional piglets were inoculated intranasally with a representative strain of the HP-PRRSV variant HuN4 with 3 different infection doses (3×103-3×105 TCID50).The results revealed that the virus variant caused severe disease in piglets and the significant clinical characteristics consisted of persistently high fever (41.0-41.9oC) and high morbidity and mortality (60-100%),the marked clinical signs of PRRS and severe histopathogenic damages in multiple organs.It induced rapid and intense humoral immune responses and seroconversion was detected in most infected pigs at 7 d post-infection (DPI).The virus vigorously replicated in vivo and the highest virus average titer was 9.7 log copies mL-1 serum at 7 DPI.Elevated levels of IFN-g and IL-10 cytokine production in serum in this study were also observed.Taken together,our results demonstrated that the HP-PRRSV variant HuN4 strain is highly pathogenic for piglets and suitable to be a reference strain of highly virulent PRRSV for evaluating the efficacy of the new vaccines.展开更多
In this study,a panel of monoclonal antibodies (mAbs) against Porcine reproductive and respiratory syndrome virus(PRRSV),named as 8C9 and4B4,were produced by fusing SP2/0 myeloma cells and spleen cells of BALB/c mice ...In this study,a panel of monoclonal antibodies (mAbs) against Porcine reproductive and respiratory syndrome virus(PRRSV),named as 8C9 and4B4,were produced by fusing SP2/0 myeloma cells and spleen cells of BALB/c mice immunized with the PRRSV (TCID50=5.5),screened by the indirect ELISA and subjected to several limiting dilutions.mAbs were then identified by biological characterization.Among the two fusion cell strains,8C9 belonged to the IgG1 subclass and 4B4 belonged to the IgG2a subclass.The titers in cell culture supernatant and abdomen liquor reached to 1:104and 1:105,respectively.The specificity test indicated that the two cells had specific reactions for the PRRSV and GP5 protein respectively,and no reaction with Classical swine fever virus (CSFV) or Swine vesicular disease virus (SVDV).The molecular weights of the heavy chain and light chain were about 45.0 kDa and 25.0 kDa,respectively.In neutralization activity tests,the results showed that the prepared mAb 4B4 can protect 50% of cells with no CPE in dilution up to 1:512,but mAB 8C9 has no neutralization activities to PRRSV.展开更多
Background:Porcine reproductive and respiratory syndrome virus(PRRSV),and particularly its highly pathogenic genotype(HP-PRRSV),have caused massive economic losses to the global swine industry.Results:To rapidly ident...Background:Porcine reproductive and respiratory syndrome virus(PRRSV),and particularly its highly pathogenic genotype(HP-PRRSV),have caused massive economic losses to the global swine industry.Results:To rapidly identify HP-PRRSV,we developed a direct real-time reverse transcription polymerase chain reaction method(dRT-PCR) that could detect the virus from serum specimen without the need of RNA purification.Our dRT-PCR assay can be completed in 1.5 h from when a sample is received to obtaining a result.Additionally,the sensitivity of dRT-PCR matched that of conventional reverse transcription PCR(cRT-PCR) that used purified RNA.The lowest detection limit of HP-PRRSV was 6.3 TCID_(50) using dRT-PCR.We applied dRT-PCR assay to 144 field samples and the results showed strong consistency with those obtained by cRT-PCR.Moreover,the dRT-PCR method was able to tolerate 5-20%(v/v) serum.Conclusions:Our dRT-PCR assay allows for easier,faster,more cost-effective and higher throughput detection of HP-PRRSV compared with cRT-PCR methods.To the best of our knowledge,this is the first report to describe a real-time RT-PCR assay capable of detecting PRRSV in crude serum samples without the requirement for purifying RNA.We believe our approach has a great potential for application to other RNA viruses.展开更多
Porcine reproductive and respiratory syndrome virus (PRRSV) has been recognized as one of the most important pathogens of pigs throughout the world. In 2006, more than 10 provinces of China have experienced an epizoot...Porcine reproductive and respiratory syndrome virus (PRRSV) has been recognized as one of the most important pathogens of pigs throughout the world. In 2006, more than 10 provinces of China have experienced an epizootic outbreak of pig diseases characterized by high fever, reddened skin and high morbidity and mortality. From June 2006 to April 2007, we have investigated some clinical samples in Hubei province by RT-PCR and cloned several major genes, N, GP5 and NSP2 gene, shown in this study. Phylogenetic analysis of these genes revealed that the highly pathogenic PRRSV variant, ZB, was responsible for 2006 emergent outbreak of pig disease in Hubei province similar with those variants isolated from other provinces in China in 2006, and belongs to the NA-type PRRSV. In the PRRSV variants, the N and GP5 shear about 90% identity with prototypic ATCC VR-2332 and some typical NA-type Chinese isolates, except the 2850bp NSP2 gene (only shares 65% identity with ATCC VR-2332). But they all shear more than and 97% identity with other highly pathogenetic Chinese PRRSV strains. Additionally, there are extensive amino acid (aa) mutations in the GP5 protein and 2 deletions in the Nsp2 protein when compared with the previous isolates. Most of the variants found in 2006 epizootic outbreak of pig diseases in China were the farthest variants from the typical NA-type PRRSV in phylogenetic distance, and these diversities may be responsible for the differences in the pathogenicity observed between these variants and original Chinese PRRSV strains.展开更多
In the present study, 89 porcine reproductive and respiratory syndrome virus(PRRSV) isolates in China during 2007 to 2012 were randomly selected from the GenBank genetic sequence database. Evolutionary characteristics...In the present study, 89 porcine reproductive and respiratory syndrome virus(PRRSV) isolates in China during 2007 to 2012 were randomly selected from the GenBank genetic sequence database. Evolutionary characteristics of these isolates were analyzed based on the sequences of non-struc-tural protein 2(Nsp2) and glycoprotein 5(GP5). The genetic variations of the isolates were also compared with six representative strains. The results showed that a high degree of genetic diversity exists among the PRRSV population in China. Highly pathogenic PRRSV isolates, with a discon-tinuous deletion of a 30 amino acid residue in the Nsp2 region, remained the most dominant virus throughout 2007–2012 in China. Owing to the extensive use of representative vaccine strains, natu-ral recombination events occurred between strains. Three isolates – HH08, DY, and YN-2011 – were more closely related to vaccine strains than the other isolates. Both YN-2011 and DY were the evolu-tionary products of recombination events between strains SP and CH-1R. The results of the present study provide useful information for the epidemiology of PRRSV as well as for vaccine development.展开更多
The nonstructural protein 10(nsp10) of porcine reproductive and respiratory syndrome virus(PRRSV) encodes for helicase which plays a vital role in viral replication. In the present study, a truncated form of nsp10, te...The nonstructural protein 10(nsp10) of porcine reproductive and respiratory syndrome virus(PRRSV) encodes for helicase which plays a vital role in viral replication. In the present study, a truncated form of nsp10, termed nsp10 a, was found in PRRSV-infected cells and the production of nsp10 a was strain-specific. Mass spectrometric analysis and deletion mutagenesis indicated that nsp10 a may be short of about 70 amino acids in the N terminus of nsp10. Further studies by rescuing recombinant viruses showed that the Glu-69 in nsp10 was the key amino acid for nsp10 a production. Finally, we demonstrated that nsp10 a exerted little influence on the growth kinetics of PRRSV in vitro.展开更多
The genome of the isolate of porcine reproductive and respiratory syndrome virus (PRRSV) from China,designated HPBEDV,was sequenced and analyzed. The size of the genome of HPBEDV was 15 334 nucleotides (nt). Comparati...The genome of the isolate of porcine reproductive and respiratory syndrome virus (PRRSV) from China,designated HPBEDV,was sequenced and analyzed. The size of the genome of HPBEDV was 15 334 nucleotides (nt). Comparative analysis of HPBEDV with the genomic sequences of the domestic and other isolates (JXA1,HuN4,CH-1a,BJ-4,VR2332,and LV) revealed that HPBEDV shared 98.4,98.0,89.0,88.7,and 88.6% identity with the American strain JXA1,HuN4,CH-1a,BJ-4,and VR2332,respectively,but only 54.7% identity with the European reference strain Lelystad virus. The NSP2 gene had 2 850 nt and encoded 950 amino acids (aa),with two discontiguous deletions of 1 aa and 29 aa at positions 482 and 534-562,respectively,relative to VR-2332. Also,phylogenetic analysis with the published PRRSV genomic sequences indicated that the newly emerging isolate form a clade with the VR-2332 isolates. Therefore,HPBEDV was a novel strain with deletions in NSP2 gene.展开更多
[Objective] To diagnose swine diseases caused by CSFV (Classical swine fever virus),PRRSV (Porcine reproductive and respiratory syndrome virus) and PRV (Pseudo-rabies virus) and analyze the pathogenic characteristics....[Objective] To diagnose swine diseases caused by CSFV (Classical swine fever virus),PRRSV (Porcine reproductive and respiratory syndrome virus) and PRV (Pseudo-rabies virus) and analyze the pathogenic characteristics.[Method] The tissues and viscera of the diseased swine were collected from a hoggery in Fujian Province.DNA and RNA were extracted for PCR amplification and sequencing.ELISA method was used to determine CSFV,PRRSV and PRV infection.[Result] The sequencing analysis and ELISA results showed that the mixed infection was caused by CSFV,PRRSV and PRV.[Conclusion] The swine epidemic situation was mainly caused by CSFV and PRRSV.展开更多
The primary objective of this study was to evaluation the immune efficacy of native inactivated vaccine against porcine reproductive and respiratory syndrome virus. The experimental design included 60 gilts and 9 boar...The primary objective of this study was to evaluation the immune efficacy of native inactivated vaccine against porcine reproductive and respiratory syndrome virus. The experimental design included 60 gilts and 9 boars equal distribution in two farms free of antibody for PRRSV at the beginning of the experiment for two consecutive months. These gilts and boars were randomly assigned to three treatment groups equally designated as groupsⅠ～Ⅲ. GroupⅠwas inoculated intramuscularly with RespPRRSV/Repro vaccine. Group Ⅱ was inoculated intramuscularly with native multivalent inactivated vaccine. Group Ⅲ was sham-inoculated intramuscularly with saline as control. Gilts and boars were inoculated again at six months intervals during the consecutive 2 years. The neonatal piglets of three groups were inoculated the same vaccine as their parents one week before weaning (piglets were 25 days). Then antibody anti-PRRSV was detected in sera obtained from gilts, boars and piglets. Biological tissue samples were collected from the recently deceased or sacrificed pigs which presented with similar PRRS symptoms. Virus isolation and viral RNA using RT-nPCR were carried through in collected tissue samples, sera and semen. Productive performances of pigs were also evaluated in this project. The results showed all the indexes in groupⅡwere very similar to that of groupⅠexcept the virus isolation and viral RNA detection. Control group had more virus isolates and viral RNA detection than inoculated groups. The rate of piglets surviving, born dead and postnatal deaths and fattening differed significantly (P<(0.05)) between experiment groups and control. This was implied that pigs inoculated with native inactivated vaccine had the similarity immune efficacy to that of pigs inoculated attenuated vaccine. This is the first large-scale to evaluation the immune efficacy of native multivalent inactivated vaccine against PRRSV in field trial. Inoculating native inactivated multivalent vaccine is also an effective measure to prevent PRRS in Shanghai pig farms and this can reduce the risk of vaccine virus shedding because of inoculating the attenuated vaccine.展开更多
Porcine reproductive and respiratory syndrome virus(PRRSV)GP4 protein was prokaryotically expressed,and used as an antigen to immunize six-week-old BALB/c female mice.With conventional cell fusion method,an anti-PRRSV...Porcine reproductive and respiratory syndrome virus(PRRSV)GP4 protein was prokaryotically expressed,and used as an antigen to immunize six-week-old BALB/c female mice.With conventional cell fusion method,an anti-PRRSV GP4 protein monoclonal antibody(Mab)5F12 was successfully prepared.It was identified as IgG2b subclass and had better stability and specificity,which not only responded with recombinant PRRSV GP4 protein,but also with PRRSV.Phage display technique had varieties of applications,in particular,the identification of key antigen epitopes for the development of therapeutic and diagnostic reagents and vaccines.In this study,Mab-5F12 was used as the target for biopanning a 12-mer phage random peptide library.After four rounds of biopanning,two phage-displayed peptides,named P-A and P-G(AKFEVCSPVVLG and GVNQENMLHFSF)were identified that recognized Mab-5F12 specifically.Sequence analysis showed that one or more of the peptides exhibited partial sequence similarity to the native GP4 protein sequence,which corresponded to 69-80 and 84-95 aa segments of the HP-PRRSV GP4 protein.Furthermore,real-time quantitative RT-PCR and indirect immunofluorescence assay indicated consistently the abilities of P-A and P-G to block viral infection in Marc-145 cells and they could function as antiviral agents for PRRSV.展开更多
To develop a modified live vaccine (MLV) against porcine reproductive and respiratory syndrome virus (PRRSV), virulent CH-1a strain was attenuated by serial passages up to 130 passage (P130) in Marc-145 cells. The vir...To develop a modified live vaccine (MLV) against porcine reproductive and respiratory syndrome virus (PRRSV), virulent CH-1a strain was attenuated by serial passages up to 130 passage (P130) in Marc-145 cells. The virulence and immune efficacy of the attenuated CH-1a were evaluated in pigs. The results showed that animals inoculated with P130 did not develop any clinical sign of the disease, but produced rapid and effective humoral immune responses against PRRSV challenge, indicating that attenuated CH-1a P130 is the candidate as the effective vaccine against PRRSV. To define the potential mutations in the attenuated CH-1a genome, we sequenced and analyzed the ORF5 gene of CH-1a strain of different passages (P39, P55, P65, P70, P85, P100, P115, P120, P125, and P130) and found that three mutations (C5Y, H38Q and L146Q) which may be related with the attenuation of CH-1a. In addition, we also found a unique restriction enzyme site (TspEI) in the ORF5 gene of attenuated CH-1a, which can be used as a genetic marker to distinguish original and attenuated CH-1a.展开更多
The lack of validated tools to predict how long sow farms will remain PRRS virus-free following successful elimination of the virus has deterred veterinarians and producers from attempting to eliminate the PRRS virus ...The lack of validated tools to predict how long sow farms will remain PRRS virus-free following successful elimination of the virus has deterred veterinarians and producers from attempting to eliminate the PRRS virus from sow farms. The aim of this study was to use the database of PRRS Risk Assessments for the Breeding Herd in PADRAP to develop and validate an objective risk scoring system for predicting the likelihood of virus introduction in PRRS virus-free sow farms in the US. To overcome the challenges of dealing with a large number of variables, group lasso for logistic regression (GLLR) was applied to a retrospective dataset of PRRS Risk Assessment for the Breeding Herd surveys completed for 704 farms to develop the risk scoring system. The validity of the GLLR risk scoring system was then evaluated by testing its predictive ability on a dataset from a long-term prospective study of 196 sow farms to assess risk factors associated with how long PRRS virus-free sow farms remained PRRS virus-free. Receiver operator characteristic(ROC) curves were estimated to compare the performance of the GLLR risk scoring system to the risk scoring system based on expert opinion (EO), currently used in the PRRS Risk Assessment for the Breeding Herd, for predicting whether herds remained PRRS virus-free for 130 weeks. The GLLR risk scoring system (AUC, 0.76;95% CI, 0.67 - 0.84) performed significantly better than the EO risk scoring system (AUC, 0.36;95% CI, 0.27 - 0.46) for predicting whether to sow farms in the prospective study survived for 130 weeks (p 0.001). Dividing farms into 3 risk groups (low, medium and high) using a low and high cutoff values for the GLLR risk score was informative as the differences in the KM survival curves for the 3 groups were both clinically meaningful and statistically significant. The GLLR risk scoring system used in conjunction with the PRRS Risk Assessment for the Breeding Herd survey delivered through PADRAP appears to have the potential to help veterinarians predict the likelihood of virus introduction in PRRS virus-free sow farms in the US.展开更多
Abstract Porcine reproductive and respiratory syndrome(PRRS)is the severest disease of pigs worldwide,caused by a highly genetically diverse RNA virus,called Porcine reproductive and respiratory syndrome virus(PRRSV)....Abstract Porcine reproductive and respiratory syndrome(PRRS)is the severest disease of pigs worldwide,caused by a highly genetically diverse RNA virus,called Porcine reproductive and respiratory syndrome virus(PRRSV).The research summarized the genome characteristics of PRRSV particles and the most updated knowledge of structure protein function,and introduced the intellectual of PRRSV transmission and host immune response,which is very important for prevention and control for PRRS.A report showed that mass vaccination can stabilize the immunity of the entire herd,and this is the first required step for a PRRS eradication plan.However,the attenuated live vaccines may not achieve a valid prevention.The final goal of the EU project is to develop new generation,efficacious and safe maker vaccines that can be adapted to temporary changes and geographical differences.Robinson reported that broadly antibodies could neutralize all rapidly evolving typeⅠand typeⅡviruses,while further studies are expected to elucidate mechanisms of neutralizing antibody production and maturation and to investigate conserved epitope targets of cross-neutralization in this rapidly evolving virus.展开更多
Porcine reproductive and respiratory syndrome(PRRS)caused by PRRS virus(PRRSV)has been regarded as a persistent challenge for the swine farms worldwide.microRNAs(miRNAs)play key roles in regulating almost every import...Porcine reproductive and respiratory syndrome(PRRS)caused by PRRS virus(PRRSV)has been regarded as a persistent challenge for the swine farms worldwide.microRNAs(miRNAs)play key roles in regulating almost every important biological process,including virus-host interaction.In this study,we found that miR-204 was highly expressed in cells that were not permissive to PRRSV infection compared with cells susceptible to PRRSV infection.Subsequently,we demonstrated that overexpression of miR-204 significantly inhibited PRRSV replication in porcine alveolar macrophages(PAMs).Through bioinformatic analysis,we found that there existed a potential binding site of miR-204 on the 30UTR of microtubule associated protein 1 light chain 3B(MAP1LC3B,LC3B),a hallmark of autophagy.Applying experiments including luciferase reporter assay and UV cross-linking and immunoprecipitation(CLIP)assay,we demonstrated that miR-204 directly targeted LC3B,thereby downregulating autophagy.Meanwhile,we investigated the interplay between autophagy and PRRSV replication in PAMs,confirming that PRRSV infection induces autophagy,which in turn facilitates viral replication.Overall,we verify that miR-204 suppresses PRRSV replication via inhibiting LC3B-mediated autophagy in PAMs.These findings will provide a novel potential approach for us to develop antiviral therapeutic agents and controlling measures for future PRRSV outbreaks.展开更多
Porcine reproductive and respiratory syndrome virus(PRRSV)is characterized by its genetic variation and limited cross protection among heterologous strains.Even though several viral structural proteins have been regar...Porcine reproductive and respiratory syndrome virus(PRRSV)is characterized by its genetic variation and limited cross protection among heterologous strains.Even though several viral structural proteins have been regarded as inducers of neutralizing antibodies(NAs)against PRRSV,the mechanism underlying limited cross-neutralization among heterologous strains is still controversial.In the present study,examinations of NA cross reaction between a highly pathogenic PRRSV(HP-PRRSV)strain,JXwn06,and a low pathogenic PRRSV(LP-PRRSV)strain,HB-1/3.9,were conducted with viral neutralization assays in MARC-145 cells.None of the JXwn06-hyperimmuned pigs’sera could neutralize HB-1/3.9 in vitro and vice versa.To address the genetic variation between these two viruses that are associated with limited crossneutralization,chimeric viruses with coding regions swapped between these two strains were constructed.Viral neutralization assays indicated that variations in nonstructural protein 2(nsp2)and structural proteins together contribute to weak cross-neutralization activity between JXwn06 and HB-1/3.9.Furthermore,we substituted the nsp2-,glycoprotein2(GP2)-,GP3-,and GP4-coding regions together,or nsp2-,GP5-,and membrane(M)protein-coding regions simultaneously between these two viruses to construct chimeric viruses to test cross-neutralization reactivity with hyperimmunized sera induced by their parental viruses.The results indicated that the swapped nsp2 and GP5-M viruses increased the neutralization reactivity with the donor strain antisera in MARC-145 cells.Taken together,these results show that variations in nsp2 and GP5-M correlate with the limited neutralization reactivity between the heterologous strains HP-PRRSV JXwn06 and LP-PRRSV HB-1/3.9.展开更多
Porcine reproductive and respiratory syndrome(PRRS) is an important infectious disease caused by porcine reproductive and respiratory syndrome virus(PRRSV), leading to significant economic losses in swine industry wor...Porcine reproductive and respiratory syndrome(PRRS) is an important infectious disease caused by porcine reproductive and respiratory syndrome virus(PRRSV), leading to significant economic losses in swine industry worldwide. Although several studies have shown that PRRSV can affect the cell cycle of infected cells, it is still unclear how it manipulates the cell cycle to facilitate its proliferation. In this study, we analyzed the mRNA expression profiles of transcription factors in PRRSV-infected 3D4/21 cells by RNA-sequencing. The result shows that the expression of transcription factor DP2(TFDP2) is remarkably upregulated in PRRSV-infected cells. Further studies show that TFDP2 contributes to PRRSV proliferation and the PRRSV nucleocapsid(N) protein induces TFDP2 expression by activating C/EBPb. TFDP2 positively regulates cyclin A expression and triggers a less proportion of cells in the S phase, which contributes to PRRSV proliferation. This study proposes a novel mechanism by which PRRSV utilizes host protein to regulate the cell cycle to favor its infection. Findings from this study will help us for a better understanding of PRRSV pathogenesis.展开更多
Porcine reproductive and respiratory syndrome virus(PRRSV)is a major pathogen that causes reproductive failure and respiratory disease in pigs,resulting in devastating economic losses worldwide[1].Porcine alveolar mac...Porcine reproductive and respiratory syndrome virus(PRRSV)is a major pathogen that causes reproductive failure and respiratory disease in pigs,resulting in devastating economic losses worldwide[1].Porcine alveolar macrophages(PAMs)are the primary target cells of PRRSV[2],and the putative receptors,including CD163,CD169,and CD151,play key roles during infection[3–6].However,the understanding of PRRSV infection and pathogenesis is展开更多
基金This study was supported by the National Basic Research Priorities Programme （973 Program） of China （G1999011902） the National Natural Science Foundation of China （30470072）.
文摘Somatostatin (SS) is a hormone that inhibits the secretion of growth hormone. Immunization against SS can promote thegrowth of animals. This paper described the effects of DNA immunization on the growth and antibody response in miceand pigs immunized with a plasmid DNA encoding SS fused with GP5 of porcine reproductive and respiratory syndromevirus (PRRSV). A fragment of 180 bp encoding partial SS gene was amplified by PCR from the genomic DNA of peripheralblood mononuclear cells of pigs, and cloned as a fusion gene with PRRSV GP5 in plasmid pISGRTK3. Three times ofimmunization with the resulting plasmid pISG-SS/GP5 induced anti-GP5 antibodies in BALB/c mice and pigs, as demonstratedby GP5-specific ELISA and immunoblotting. Compared with pigs immunized with empty vector pISGRTK3, the growthperformance of pigs immunized with pISG-SS/GP5 was increased by 11.1% on the 13th week after the last vaccination. Theresults indicated the plasmid DNA encoding SS and PRRSV GP5 fusion gene elicited anti-GP5 antibodies and improvedthe growth performance of immunized pigs.
文摘Porcine reproductive and respiratory syndrome virus(PRRSV) infection is the leading cause of economic casualty in swine industry worldwide. The virus can cause reproductive failure, respiratory disease, and growth retardation in the pigs. This review deals with current status of commercial PRRS vaccines presently used to control PRRS. The review focuses on the immunogenicity, protective efficacy and safety aspects of the vaccines. Commercial PRRS modified-live virus(MLV) vaccine elicits delayed humoral and cell-mediated immune responses following vaccination. The vaccine confers late but effective protection against genetically homologous PRRSV, and partial protection against genetically heterologous virus. The MLV vaccine is of concern for its safety as the vaccine virus can revert to virulence and cause diseases. PRRS killed virus(KV) vaccine, on the other hand, is safe but confers limited protection against either homologous or heterologous virus. The KV vaccine yet helps reduce disease severity when administered to the PRRSV-infected pigs. Although efforts have been made to improve the immunogenicity, ef-ficacy and safety of PRRS vaccines, a better vaccine is still needed in order to protect against PRRSV.
基金supported by a grant from the Out-standing Person Innovation Foundation of Henan,China(0621002100)
文摘A multiplex reverse transcriptase-polymerase chain reaction(multiplex RT-PCR) assay was developed and subsequently evaluated for its efficacy in the detection of multiple viral infections simultaneously,in swine.Specific primers for each of the 3 RNA viruses,North American genotype porcine reproductive and respiratory syndrome virus,Japanese encephalitis virus,and swine influenza virus,were used in the testing procedure.The assay was shown to be highly sensitive because it could detect as little as 10-5 ng of each of the respective amplicons in a single sample containing a composite of all 3 viruses.The assay was also effective in detecting one or more of the same viruses in various combinations in specimens,including lymph nodes,lungs,spleens,and tonsils,collected from clinically ill pigs and in spleen specimens collected from aborted pig fetuses.The results from the multiplex RT-PCR were confirmed by virus isolation.The relative efficiency(compared to the efficiency of separate assays for each virus) and apparent sensitivity of the multiplex RT-PCR method show that this method has potential for application in routine molecular diagnostic procedures.
基金supported by grants from the National Basic Research Program of China (973 Program,2005CB523200)the National High-Tech Research and Development Program of China (863 Program,2006AA10A20 4)+1 种基金the National Key Technology R&D Program (2006BAD 06A04/18/01/03)the National Natural Science Foundation of China (30470072)
文摘Since May 2006,a highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV) variant characterized by 30 amino acids deletion within its NSP2-coding region emerged and caused extensive economic losses to China's pig industry.To investigate the in vivo pathogenicity and immune responses of the newly emerging PRRSV,3 groups of 60-d-old conventional piglets were inoculated intranasally with a representative strain of the HP-PRRSV variant HuN4 with 3 different infection doses (3×103-3×105 TCID50).The results revealed that the virus variant caused severe disease in piglets and the significant clinical characteristics consisted of persistently high fever (41.0-41.9oC) and high morbidity and mortality (60-100%),the marked clinical signs of PRRS and severe histopathogenic damages in multiple organs.It induced rapid and intense humoral immune responses and seroconversion was detected in most infected pigs at 7 d post-infection (DPI).The virus vigorously replicated in vivo and the highest virus average titer was 9.7 log copies mL-1 serum at 7 DPI.Elevated levels of IFN-g and IL-10 cytokine production in serum in this study were also observed.Taken together,our results demonstrated that the HP-PRRSV variant HuN4 strain is highly pathogenic for piglets and suitable to be a reference strain of highly virulent PRRSV for evaluating the efficacy of the new vaccines.
基金Chinese National Technology Researchand Development Program (863 Program,2006AA10A204)
文摘In this study,a panel of monoclonal antibodies (mAbs) against Porcine reproductive and respiratory syndrome virus(PRRSV),named as 8C9 and4B4,were produced by fusing SP2/0 myeloma cells and spleen cells of BALB/c mice immunized with the PRRSV (TCID50=5.5),screened by the indirect ELISA and subjected to several limiting dilutions.mAbs were then identified by biological characterization.Among the two fusion cell strains,8C9 belonged to the IgG1 subclass and 4B4 belonged to the IgG2a subclass.The titers in cell culture supernatant and abdomen liquor reached to 1:104and 1:105,respectively.The specificity test indicated that the two cells had specific reactions for the PRRSV and GP5 protein respectively,and no reaction with Classical swine fever virus (CSFV) or Swine vesicular disease virus (SVDV).The molecular weights of the heavy chain and light chain were about 45.0 kDa and 25.0 kDa,respectively.In neutralization activity tests,the results showed that the prepared mAb 4B4 can protect 50% of cells with no CPE in dilution up to 1:512,but mAB 8C9 has no neutralization activities to PRRSV.
基金supported in part by the National Basic Research Program of China(973 Program,2012CB124701)National Natural Science Foundation of China No.81170047,81370151(to DG)+6 种基金Shenzhen overseas high-level talentsinnovation program No.YFZZ20111009(to DG)Shenzhen Nanshan Core Technology Program No.KC2013JSJS0020AShenzhen Municipal Basic Research Program No.JCYJ20130329120507746(to KK)Postdoctoral Science Foundation of China No.2013 M542203(to KK)Hubei Province Research and Development Project No.2011BBB080(to KY)Project supported by the Key Natural Science Foundation of Hubei Province,China No.2012FFA067(to YT)the Opening Subject of Hubei Key Laboratory of Animal Embryo and Molecular Breeding No.2012ZD156(to KY)
文摘Background:Porcine reproductive and respiratory syndrome virus(PRRSV),and particularly its highly pathogenic genotype(HP-PRRSV),have caused massive economic losses to the global swine industry.Results:To rapidly identify HP-PRRSV,we developed a direct real-time reverse transcription polymerase chain reaction method(dRT-PCR) that could detect the virus from serum specimen without the need of RNA purification.Our dRT-PCR assay can be completed in 1.5 h from when a sample is received to obtaining a result.Additionally,the sensitivity of dRT-PCR matched that of conventional reverse transcription PCR(cRT-PCR) that used purified RNA.The lowest detection limit of HP-PRRSV was 6.3 TCID_(50) using dRT-PCR.We applied dRT-PCR assay to 144 field samples and the results showed strong consistency with those obtained by cRT-PCR.Moreover,the dRT-PCR method was able to tolerate 5-20%(v/v) serum.Conclusions:Our dRT-PCR assay allows for easier,faster,more cost-effective and higher throughput detection of HP-PRRSV compared with cRT-PCR methods.To the best of our knowledge,this is the first report to describe a real-time RT-PCR assay capable of detecting PRRSV in crude serum samples without the requirement for purifying RNA.We believe our approach has a great potential for application to other RNA viruses.
基金supported in part by a National Key Technologies R&D Program (2006BAD06A01) National "973 Project" (2005CB523000, 2006CB- 933102) from the Ministry of Science and Technology, People’s Republic of China.
文摘Porcine reproductive and respiratory syndrome virus (PRRSV) has been recognized as one of the most important pathogens of pigs throughout the world. In 2006, more than 10 provinces of China have experienced an epizootic outbreak of pig diseases characterized by high fever, reddened skin and high morbidity and mortality. From June 2006 to April 2007, we have investigated some clinical samples in Hubei province by RT-PCR and cloned several major genes, N, GP5 and NSP2 gene, shown in this study. Phylogenetic analysis of these genes revealed that the highly pathogenic PRRSV variant, ZB, was responsible for 2006 emergent outbreak of pig disease in Hubei province similar with those variants isolated from other provinces in China in 2006, and belongs to the NA-type PRRSV. In the PRRSV variants, the N and GP5 shear about 90% identity with prototypic ATCC VR-2332 and some typical NA-type Chinese isolates, except the 2850bp NSP2 gene (only shares 65% identity with ATCC VR-2332). But they all shear more than and 97% identity with other highly pathogenetic Chinese PRRSV strains. Additionally, there are extensive amino acid (aa) mutations in the GP5 protein and 2 deletions in the Nsp2 protein when compared with the previous isolates. Most of the variants found in 2006 epizootic outbreak of pig diseases in China were the farthest variants from the typical NA-type PRRSV in phylogenetic distance, and these diversities may be responsible for the differences in the pathogenicity observed between these variants and original Chinese PRRSV strains.
基金supported by the Jilin Province Science and Technology Development Project(No.20140101123JC)the Fundamental Research Fund of Jilin Universitythe Program for Changjiang Scholars and Innovative Research Team in University(No.IRT1248)
文摘In the present study, 89 porcine reproductive and respiratory syndrome virus(PRRSV) isolates in China during 2007 to 2012 were randomly selected from the GenBank genetic sequence database. Evolutionary characteristics of these isolates were analyzed based on the sequences of non-struc-tural protein 2(Nsp2) and glycoprotein 5(GP5). The genetic variations of the isolates were also compared with six representative strains. The results showed that a high degree of genetic diversity exists among the PRRSV population in China. Highly pathogenic PRRSV isolates, with a discon-tinuous deletion of a 30 amino acid residue in the Nsp2 region, remained the most dominant virus throughout 2007–2012 in China. Owing to the extensive use of representative vaccine strains, natu-ral recombination events occurred between strains. Three isolates – HH08, DY, and YN-2011 – were more closely related to vaccine strains than the other isolates. Both YN-2011 and DY were the evolu-tionary products of recombination events between strains SP and CH-1R. The results of the present study provide useful information for the epidemiology of PRRSV as well as for vaccine development.
基金supported by the National Key Technology R&D Program of China (2015BAD12B01-2)the Major Program of National Natural Science Foundation of China (31490603)the earmarked fund for Modern Agroindustry Technology Research System of China (CARS-36)
文摘The nonstructural protein 10(nsp10) of porcine reproductive and respiratory syndrome virus(PRRSV) encodes for helicase which plays a vital role in viral replication. In the present study, a truncated form of nsp10, termed nsp10 a, was found in PRRSV-infected cells and the production of nsp10 a was strain-specific. Mass spectrometric analysis and deletion mutagenesis indicated that nsp10 a may be short of about 70 amino acids in the N terminus of nsp10. Further studies by rescuing recombinant viruses showed that the Glu-69 in nsp10 was the key amino acid for nsp10 a production. Finally, we demonstrated that nsp10 a exerted little influence on the growth kinetics of PRRSV in vitro.
基金supported by the National Natural Sci-ence Foundation of China (30671563,30700597)the Natural Science Foundation of Gansu Province,China (0803RJZA050)
文摘The genome of the isolate of porcine reproductive and respiratory syndrome virus (PRRSV) from China,designated HPBEDV,was sequenced and analyzed. The size of the genome of HPBEDV was 15 334 nucleotides (nt). Comparative analysis of HPBEDV with the genomic sequences of the domestic and other isolates (JXA1,HuN4,CH-1a,BJ-4,VR2332,and LV) revealed that HPBEDV shared 98.4,98.0,89.0,88.7,and 88.6% identity with the American strain JXA1,HuN4,CH-1a,BJ-4,and VR2332,respectively,but only 54.7% identity with the European reference strain Lelystad virus. The NSP2 gene had 2 850 nt and encoded 950 amino acids (aa),with two discontiguous deletions of 1 aa and 29 aa at positions 482 and 534-562,respectively,relative to VR-2332. Also,phylogenetic analysis with the published PRRSV genomic sequences indicated that the newly emerging isolate form a clade with the VR-2332 isolates. Therefore,HPBEDV was a novel strain with deletions in NSP2 gene.
基金funded by the Major Project of Regional Science and Technology of Fujian Province (2009N3013)the Innovation Platform Construction Project of the Science and Technology Department of Fujian Province (2008N2005)
文摘[Objective] To diagnose swine diseases caused by CSFV (Classical swine fever virus),PRRSV (Porcine reproductive and respiratory syndrome virus) and PRV (Pseudo-rabies virus) and analyze the pathogenic characteristics.[Method] The tissues and viscera of the diseased swine were collected from a hoggery in Fujian Province.DNA and RNA were extracted for PCR amplification and sequencing.ELISA method was used to determine CSFV,PRRSV and PRV infection.[Result] The sequencing analysis and ELISA results showed that the mixed infection was caused by CSFV,PRRSV and PRV.[Conclusion] The swine epidemic situation was mainly caused by CSFV and PRRSV.
文摘The primary objective of this study was to evaluation the immune efficacy of native inactivated vaccine against porcine reproductive and respiratory syndrome virus. The experimental design included 60 gilts and 9 boars equal distribution in two farms free of antibody for PRRSV at the beginning of the experiment for two consecutive months. These gilts and boars were randomly assigned to three treatment groups equally designated as groupsⅠ～Ⅲ. GroupⅠwas inoculated intramuscularly with RespPRRSV/Repro vaccine. Group Ⅱ was inoculated intramuscularly with native multivalent inactivated vaccine. Group Ⅲ was sham-inoculated intramuscularly with saline as control. Gilts and boars were inoculated again at six months intervals during the consecutive 2 years. The neonatal piglets of three groups were inoculated the same vaccine as their parents one week before weaning (piglets were 25 days). Then antibody anti-PRRSV was detected in sera obtained from gilts, boars and piglets. Biological tissue samples were collected from the recently deceased or sacrificed pigs which presented with similar PRRS symptoms. Virus isolation and viral RNA using RT-nPCR were carried through in collected tissue samples, sera and semen. Productive performances of pigs were also evaluated in this project. The results showed all the indexes in groupⅡwere very similar to that of groupⅠexcept the virus isolation and viral RNA detection. Control group had more virus isolates and viral RNA detection than inoculated groups. The rate of piglets surviving, born dead and postnatal deaths and fattening differed significantly (P<(0.05)) between experiment groups and control. This was implied that pigs inoculated with native inactivated vaccine had the similarity immune efficacy to that of pigs inoculated attenuated vaccine. This is the first large-scale to evaluation the immune efficacy of native multivalent inactivated vaccine against PRRSV in field trial. Inoculating native inactivated multivalent vaccine is also an effective measure to prevent PRRS in Shanghai pig farms and this can reduce the risk of vaccine virus shedding because of inoculating the attenuated vaccine.
基金Supported by the National Natural Science Foundation of China(31372438,31200122)
文摘Porcine reproductive and respiratory syndrome virus(PRRSV)GP4 protein was prokaryotically expressed,and used as an antigen to immunize six-week-old BALB/c female mice.With conventional cell fusion method,an anti-PRRSV GP4 protein monoclonal antibody(Mab)5F12 was successfully prepared.It was identified as IgG2b subclass and had better stability and specificity,which not only responded with recombinant PRRSV GP4 protein,but also with PRRSV.Phage display technique had varieties of applications,in particular,the identification of key antigen epitopes for the development of therapeutic and diagnostic reagents and vaccines.In this study,Mab-5F12 was used as the target for biopanning a 12-mer phage random peptide library.After four rounds of biopanning,two phage-displayed peptides,named P-A and P-G(AKFEVCSPVVLG and GVNQENMLHFSF)were identified that recognized Mab-5F12 specifically.Sequence analysis showed that one or more of the peptides exhibited partial sequence similarity to the native GP4 protein sequence,which corresponded to 69-80 and 84-95 aa segments of the HP-PRRSV GP4 protein.Furthermore,real-time quantitative RT-PCR and indirect immunofluorescence assay indicated consistently the abilities of P-A and P-G to block viral infection in Marc-145 cells and they could function as antiviral agents for PRRSV.
基金supported by the National High Technology Research and Development Program of China(2011AA10A213)the Key Technology R&D Program of Harbin, China(2010AA6AN083)the Excellent Youth Foundation of Heilongjiang Province of China(JC201020)
文摘To develop a modified live vaccine (MLV) against porcine reproductive and respiratory syndrome virus (PRRSV), virulent CH-1a strain was attenuated by serial passages up to 130 passage (P130) in Marc-145 cells. The virulence and immune efficacy of the attenuated CH-1a were evaluated in pigs. The results showed that animals inoculated with P130 did not develop any clinical sign of the disease, but produced rapid and effective humoral immune responses against PRRSV challenge, indicating that attenuated CH-1a P130 is the candidate as the effective vaccine against PRRSV. To define the potential mutations in the attenuated CH-1a genome, we sequenced and analyzed the ORF5 gene of CH-1a strain of different passages (P39, P55, P65, P70, P85, P100, P115, P120, P125, and P130) and found that three mutations (C5Y, H38Q and L146Q) which may be related with the attenuation of CH-1a. In addition, we also found a unique restriction enzyme site (TspEI) in the ORF5 gene of attenuated CH-1a, which can be used as a genetic marker to distinguish original and attenuated CH-1a.
文摘The lack of validated tools to predict how long sow farms will remain PRRS virus-free following successful elimination of the virus has deterred veterinarians and producers from attempting to eliminate the PRRS virus from sow farms. The aim of this study was to use the database of PRRS Risk Assessments for the Breeding Herd in PADRAP to develop and validate an objective risk scoring system for predicting the likelihood of virus introduction in PRRS virus-free sow farms in the US. To overcome the challenges of dealing with a large number of variables, group lasso for logistic regression (GLLR) was applied to a retrospective dataset of PRRS Risk Assessment for the Breeding Herd surveys completed for 704 farms to develop the risk scoring system. The validity of the GLLR risk scoring system was then evaluated by testing its predictive ability on a dataset from a long-term prospective study of 196 sow farms to assess risk factors associated with how long PRRS virus-free sow farms remained PRRS virus-free. Receiver operator characteristic(ROC) curves were estimated to compare the performance of the GLLR risk scoring system to the risk scoring system based on expert opinion (EO), currently used in the PRRS Risk Assessment for the Breeding Herd, for predicting whether herds remained PRRS virus-free for 130 weeks. The GLLR risk scoring system (AUC, 0.76;95% CI, 0.67 - 0.84) performed significantly better than the EO risk scoring system (AUC, 0.36;95% CI, 0.27 - 0.46) for predicting whether to sow farms in the prospective study survived for 130 weeks (p 0.001). Dividing farms into 3 risk groups (low, medium and high) using a low and high cutoff values for the GLLR risk score was informative as the differences in the KM survival curves for the 3 groups were both clinically meaningful and statistically significant. The GLLR risk scoring system used in conjunction with the PRRS Risk Assessment for the Breeding Herd survey delivered through PADRAP appears to have the potential to help veterinarians predict the likelihood of virus introduction in PRRS virus-free sow farms in the US.
基金Supported by the Natural Science Research Subject of Minhang Center(2015MHZ041)
文摘Abstract Porcine reproductive and respiratory syndrome(PRRS)is the severest disease of pigs worldwide,caused by a highly genetically diverse RNA virus,called Porcine reproductive and respiratory syndrome virus(PRRSV).The research summarized the genome characteristics of PRRSV particles and the most updated knowledge of structure protein function,and introduced the intellectual of PRRSV transmission and host immune response,which is very important for prevention and control for PRRS.A report showed that mass vaccination can stabilize the immunity of the entire herd,and this is the first required step for a PRRS eradication plan.However,the attenuated live vaccines may not achieve a valid prevention.The final goal of the EU project is to develop new generation,efficacious and safe maker vaccines that can be adapted to temporary changes and geographical differences.Robinson reported that broadly antibodies could neutralize all rapidly evolving typeⅠand typeⅡviruses,while further studies are expected to elucidate mechanisms of neutralizing antibody production and maturation and to investigate conserved epitope targets of cross-neutralization in this rapidly evolving virus.
基金This study was supported by the National Natural Science Foundation of China(Grant No.31630076),Chinathe National Major Special Project on New Varieties Cultivation for Transgenic Organisms(grant no.2016ZX08009-003-006),China.
文摘Porcine reproductive and respiratory syndrome(PRRS)caused by PRRS virus(PRRSV)has been regarded as a persistent challenge for the swine farms worldwide.microRNAs(miRNAs)play key roles in regulating almost every important biological process,including virus-host interaction.In this study,we found that miR-204 was highly expressed in cells that were not permissive to PRRSV infection compared with cells susceptible to PRRSV infection.Subsequently,we demonstrated that overexpression of miR-204 significantly inhibited PRRSV replication in porcine alveolar macrophages(PAMs).Through bioinformatic analysis,we found that there existed a potential binding site of miR-204 on the 30UTR of microtubule associated protein 1 light chain 3B(MAP1LC3B,LC3B),a hallmark of autophagy.Applying experiments including luciferase reporter assay and UV cross-linking and immunoprecipitation(CLIP)assay,we demonstrated that miR-204 directly targeted LC3B,thereby downregulating autophagy.Meanwhile,we investigated the interplay between autophagy and PRRSV replication in PAMs,confirming that PRRSV infection induces autophagy,which in turn facilitates viral replication.Overall,we verify that miR-204 suppresses PRRSV replication via inhibiting LC3B-mediated autophagy in PAMs.These findings will provide a novel potential approach for us to develop antiviral therapeutic agents and controlling measures for future PRRSV outbreaks.
基金supported by the Major Program of National Natural Science Foundation of China (31490603, 31572549)the National Key Technology R & D Program of China (2015BAD12B01-2)
文摘Porcine reproductive and respiratory syndrome virus(PRRSV)is characterized by its genetic variation and limited cross protection among heterologous strains.Even though several viral structural proteins have been regarded as inducers of neutralizing antibodies(NAs)against PRRSV,the mechanism underlying limited cross-neutralization among heterologous strains is still controversial.In the present study,examinations of NA cross reaction between a highly pathogenic PRRSV(HP-PRRSV)strain,JXwn06,and a low pathogenic PRRSV(LP-PRRSV)strain,HB-1/3.9,were conducted with viral neutralization assays in MARC-145 cells.None of the JXwn06-hyperimmuned pigs’sera could neutralize HB-1/3.9 in vitro and vice versa.To address the genetic variation between these two viruses that are associated with limited crossneutralization,chimeric viruses with coding regions swapped between these two strains were constructed.Viral neutralization assays indicated that variations in nonstructural protein 2(nsp2)and structural proteins together contribute to weak cross-neutralization activity between JXwn06 and HB-1/3.9.Furthermore,we substituted the nsp2-,glycoprotein2(GP2)-,GP3-,and GP4-coding regions together,or nsp2-,GP5-,and membrane(M)protein-coding regions simultaneously between these two viruses to construct chimeric viruses to test cross-neutralization reactivity with hyperimmunized sera induced by their parental viruses.The results indicated that the swapped nsp2 and GP5-M viruses increased the neutralization reactivity with the donor strain antisera in MARC-145 cells.Taken together,these results show that variations in nsp2 and GP5-M correlate with the limited neutralization reactivity between the heterologous strains HP-PRRSV JXwn06 and LP-PRRSV HB-1/3.9.
基金This work was supported by the National Key Research and Development Program of China(2018YFD0500500)the National Natural Science Foundation of China(31272540)。
文摘Porcine reproductive and respiratory syndrome(PRRS) is an important infectious disease caused by porcine reproductive and respiratory syndrome virus(PRRSV), leading to significant economic losses in swine industry worldwide. Although several studies have shown that PRRSV can affect the cell cycle of infected cells, it is still unclear how it manipulates the cell cycle to facilitate its proliferation. In this study, we analyzed the mRNA expression profiles of transcription factors in PRRSV-infected 3D4/21 cells by RNA-sequencing. The result shows that the expression of transcription factor DP2(TFDP2) is remarkably upregulated in PRRSV-infected cells. Further studies show that TFDP2 contributes to PRRSV proliferation and the PRRSV nucleocapsid(N) protein induces TFDP2 expression by activating C/EBPb. TFDP2 positively regulates cyclin A expression and triggers a less proportion of cells in the S phase, which contributes to PRRSV proliferation. This study proposes a novel mechanism by which PRRSV utilizes host protein to regulate the cell cycle to favor its infection. Findings from this study will help us for a better understanding of PRRSV pathogenesis.
基金supported in part by the National Key Research and Development Program of China (2017YFA0104401)the National Natural Science Foundation of China (31422037 and 31571522)
文摘Porcine reproductive and respiratory syndrome virus(PRRSV)is a major pathogen that causes reproductive failure and respiratory disease in pigs,resulting in devastating economic losses worldwide[1].Porcine alveolar macrophages(PAMs)are the primary target cells of PRRSV[2],and the putative receptors,including CD163,CD169,and CD151,play key roles during infection[3–6].However,the understanding of PRRSV infection and pathogenesis is
