Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| dna vaccination of pigs with open reading frame 1-7 of prrs virus. | we cloned all open reading frames of a danish isolate of porcine reproductive and respiratory syndrome (prrs) virus in dna vaccination vectors. pigs were vaccinated using a gene gun with each single construct (orf1, orf2, orf3, orf4, orf5, orf6, or orf7) or combinations thereof. vaccination with orf7 consistently induced antibodies after three vaccinations, while antibodies were only sporadically detected in the remaining groups. after six vaccinations, all pigs were inoculated with prrs virus a ... | 2004 | 15315842 |
| characterization of heteroclite subgenomic rnas associated with prrsv infection. | in this study, porcine reproductive and respiratory syndrome virus (prrsv) heteroclite (uncommon forms) rnas were characterized. nucleotide sequencing of 11 additional defective rna species verified that heteroclites are formed between the 5' and 3' termini of prrsv at short stretches of identity, with variability seen between the junction sites utilized. northern blot and rt-pcr analyses indicated that heteroclite rna species were likely to be packaged into purified virions. to study whether he ... | 2004 | 15325083 |
| interferon type i response in porcine reproductive and respiratory syndrome virus-infected marc-145 cells. | infection by porcine reproductive and respiratory syndrome virus (prrsv) results in a weak induction of the innate immune response. there are many genes that collectively comprise this response and the extent to which each gene responds to prrsv infection is unclear and warrants further investigation. to this end, we have utilized real-time pcr using sybr green i dye-based detection to quantify transcript abundance of the type i interferons (ifn-alpha and -beta) and ifn-beta transcriptional enha ... | 2004 | 15338318 |
| an assessment of sanitation protocols for commercial transport vehicles contaminated with porcine reproductive and respiratory syndrome virus. | the objective of this study was to develop and test a rapid (< 2 h) sanitation protocol designed for porcine reproductive and respiratory syndrome virus (prrsv) positive commercial transport vehicles involving cold water washing and disinfection via fumigation using scale models of weaned pig trailers. the study consisted of 2 phases. following experimental contamination of model trailers with prrsv mn 30-100 (5 x 10(5)tcid50), phase 1 evaluated the presence or absence of prrsv rna by polymerase ... | 2004 | 15352546 |
| increased production of proinflammatory cytokines following infection with porcine reproductive and respiratory syndrome virus and mycoplasma hyopneumoniae. | induction of the proinflammatory cytokines interleukin-1 (il-1) (alpha and beta), il-6, il-8, il-10, il-12, and tumor necrosis factor alpha (tnf-alpha) in pulmonary alveolar macrophages (pams) was assessed following experimental infection with porcine reproductive and respiratory syndrome virus (prrsv) and/or mycoplasma hyopneumoniae by using in vivo and in vitro models. the in vivo model consisted of pigs infected with prrsv and/or m. hyopneumoniae and necropsied at 10, 28, or 42 days postinfec ... | 2004 | 15358650 |
| detection of u.s., lelystad, and european-like porcine reproductive and respiratory syndrome viruses and relative quantitation in boar semen and serum samples by real-time pcr. | transmission of porcine reproductive and respiratory syndrome virus (prrsv) via boar semen has been documented. since semen is widely disseminated for artificial insemination and the virus can cause significant health and economic consequences, it is essential to have well-validated, rapid diagnostic techniques to detect and quantitate the virus for diagnostic and research purposes. previously, boar semen was tested by a nested pcr (npcr) assay which was compared to the "gold standard" swine bio ... | 2004 | 15472293 |
| instability of the restriction fragment length polymorphism pattern of open reading frame 5 of porcine reproductive and respiratory syndrome virus during sequential pig-to-pig passages. | restriction fragment length polymorphism (rflp) analysis is one of the tools commonly used to study the molecular epidemiology of porcine reproductive and respiratory syndrome viruses (prrsvs). as prrsvs are genetically variable, the stability of the rflp pattern of a prrsv during in vivo replication was evaluated by carrying out 13 sequential pig-to-pig passages (p1 to p13) of prrsv atcc vr-2332 in three independent pig lines for a total of 727 days. during p1 the pigs were inoculated with a ho ... | 2004 | 15472294 |
| impact of genetic diversity of european-type porcine reproductive and respiratory syndrome virus strains on vaccine efficacy. | the aim of this study was to find out how efficiently pigs that are vaccinated with an attenuated porcine reproductive and respiratory syndrome virus (prrsv) vaccine based on a virus from the lelystad cluster are protected against a european wild-type strain from the same or another genetic cluster. two experiments were performed. in each experiment, 5-week-old prrsv-seronegative pigs were vaccinated intramuscularly with 10(4.5) tcid50 of a commercial vaccine based on a european virus strain fro ... | 2004 | 15474708 |
| spatial dispersal of porcine reproductive and respiratory syndrome virus-contaminated flies after contact with experimentally infected pigs. | to determine whether flies can acquire porcine reproductive and respiratory syndrome virus (prrsv) and disperse the virus throughout a designated area. | 2004 | 15478779 |
| the immune response to equine arteritis virus: potential lessons for other arteriviruses. | the members of the family arteriviridae, genus arterivirus, include equine arteritis virus (eav), porcine reproductive and respiratory syndrome virus (prrsv), lactate dehydrogenase-elevating virus (ldv) of mice, and simian hemorrhagic fever virus (shfv). prrsv is the newest member of the family (first isolated in north america and europe in the early 1990s), whereas the other three viruses were recognized earlier (eav in 1953, ldv in 1960, and shfv in 1964). although arterivirus infections are s ... | 2004 | 15507299 |
| apoptosis and porcine reproductive and respiratory syndrome virus. | despite numerous studies examining the possible induction of apoptosis in porcine reproductive and respiratory syndrome virus (prrsv)-infected cells, it remains unclear if prrsv infection results in direct apoptotic induction. there is clear evidence that apoptotic cells are present in tissues from prrsv-infected pigs. however, many of these studies have failed to show that the apoptotic cells are infected with prrsv. this has led some investigators to propose that "bystander" cells, not infecte ... | 2004 | 15507300 |
| infectious cdna clones of porcine reproductive and respiratory syndrome virus and their potential as vaccine vectors. | full-length infectious cdna clones have recently become available for both european and north american genotypes of porcine reproductive and respiratory syndrome virus (prrsv), and it is now possible to alter the prrsv genome and create genetically defined mutant viruses. among many possible applications of the prrsv infectious cdna clones, development of genetically modified vaccines is of particular interest. using infectious clones, the prrsv genome has been manipulated by changing individual ... | 2004 | 15507301 |
| role of neutralizing antibodies in prrsv protective immunity. | little has been known about the components of the immune system that are effective in the protection of a pig against prrsv infection. although antibodies were initially perceived as a deleterious, ineffective component of the prrsv-specific immune response, neutralizing antibodies (na) are now considered to be an important correlate of protective immunity against prrsv. this paper reviews the current knowledge on arterivirus-specific na, the role that na have in protection against infection wit ... | 2004 | 15507302 |
| the combination of prrs virus and bacterial endotoxin as a model for multifactorial respiratory disease in pigs. | this paper reviews in vivo studies on the interaction between porcine reproductive and respiratory syndrome virus (prrsv) and lps performed in the authors' laboratory. the main aim was to develop a reproducible model to study the pathogenesis of prrsv-induced multifactorial respiratory disease. the central hypothesis was that respiratory disease results from an overproduction of proinflammatory cytokines in the lungs. in a first series of studies, prrsv was shown to be a poor inducer of tnf-alph ... | 2004 | 15507303 |
| effect of virus-specific antibodies on attachment, internalization and infection of porcine reproductive and respiratory syndrome virus in primary macrophages. | porcine reproductive and respiratory syndrome virus (prrsv) induces respiratory distress in young pigs and reproductive failure in sows. in prrsv infected pigs, virus persists for several weeks to several months. although ipma antibodies are detected from 7 days post inoculation (pi), virus neutralizing (vn) antibodies are commonly detected starting from 3 weeks pi with an sn test on marc-145 cells. since infection of marc-145 cells is quite different compared to infection of macrophages, the in ... | 2004 | 15507304 |
| differential host cell gene expression regulated by the porcine reproductive and respiratory syndrome virus gp4 and gp5 glycoproteins. | the porcine reproductive and respiratory syndrome virus (prrsv) gp4 and gp5 proteins are two membrane-associated viral glycoproteins that have been shown to induce neutralizing antibodies. in the present study, the host cell gene expression profiles altered by the gp4 and gp5 proteins were investigated by the use of dna microarrays. sublines of marc-145 and hela cells were established by stable transfection with open reading frame (orf)4 and orf5 of prrsv, respectively, and differential gene exp ... | 2004 | 15507305 |
| deciphering the involvement of innate immune factors in the development of the host response to prrsv vaccination. | the natural response of pigs to porcine reproductive and respiratory syndrome virus (prrsv) infections and vaccinations needs to be altered so that better protection is afforded against both homologous and heterologous challenges by this pathogen. to address this problem, real-time gene expression assays were coupled with cytokine elispot and protein analyses to assess the nature of the anti-prrsv response of pigs immunized with modified live virus (mlv) vaccine. although t helper 1 (th1) immuni ... | 2004 | 15507306 |
| porcine reproductive and respiratory syndrome virus field isolates differ in in vitro interferon phenotypes. | type i interferons (ifn-alpha and -beta) play an important role in the innate host defense against viral infection by inducing antiviral responses. in addition to direct antiviral activities, type i ifn serves as an important link between the innate and adaptive immune response through multiple mechanisms. therefore, the outcome of a viral infection can be affected by ifn induction and the ifn sensitivity of a virus. north american porcine reproductive and respiratory syndrome virus (prrsv) fiel ... | 2004 | 15507307 |
| pathogenic and humoral immune responses to porcine reproductive and respiratory syndrome virus (prrsv) are related to viral load in acute infection. | although much research has been performed on porcine reproductive and respiratory syndrome virus (prrsv), little quantitative information is available on the relationships between virulence and in vivo virus replication, among isolates recovered at different times in the history of prrs, or the relative levels of virulence associated with individual virus isolates. in this study, the in vivo growth properties of virulent field isolates and attenuated prrsv isolates were compared. the results sho ... | 2004 | 15507308 |
| monoclonal antibody analysis of porcine reproductive and respiratory syndrome virus epitopes associated with antibody-dependent enhancement and neutralization of virus infection. | enhanced infection and replication of porcine reproductive and respiratory syndrome (prrs) virus in the presence of specific antibody has been demonstrated in vitro and in vivo, a phenomenon known as antibody-dependent enhancement (ade). ade is considered to be a significant obstacle to developing effective vaccines for many viruses for which ade has been reported, since virus-specific antibodies of maternal origin or those conferred by vaccination can facilitate the entry of the virus into targ ... | 2004 | 15507309 |
| the primary gp5 neutralization epitope of north american isolates of porcine reproductive and respiratory syndrome virus. | i have used indirect elisa with overlapping synthetic peptides representing the gp5 ectodomain to study the generation and specificity of peptide-binding abs in pigs that were infected in utero with porcine reproductive and respiratory syndrome virus (prrsv) strain vr2332 and in north american field sera submitted for prrsv infection diagnosis. peptide-binding abs appeared in sera of the vr2332-infected pigs within about 30 days post-farrowing (dpf), reaching maximum titers 100-200 dpf and then ... | 2004 | 15507310 |
| construction and evaluation of genetically engineered replication-defective porcine reproductive and respiratory syndrome virus vaccine candidates. | porcine reproductive and respiratory syndrome virus (prrsv) is an emerging pathogen causing significant economic losses in the swine industry worldwide. two novel gene-deleted viruses were constructed and evaluated as vaccine candidates. using the full-length infectious cdna clone of north american prrs isolate p129, the orf2 and orf4 genes (which encoded minor structural glycoproteins gp2a/2b and gp4, respectively) were individually deleted from the viral genome. both deletion mutants were non- ... | 2004 | 15507311 |
| immune responses of swine following dna immunization with plasmids encoding porcine reproductive and respiratory syndrome virus orfs 5 and 7, and porcine il-2 and ifngamma. | in the present study, five eukaryotic double-gene expression plasmids containing porcine reproductive and respiratory syndrome virus (prrsv) orf5 and orf7 genes combined with cdnas encoding porcine ifngamma and il-2 were constructed for evaluation as prrsv vaccine candidates. after immunization and viral challenge, two of three pigs immunized with piresorf5/ifngamma, one of three pigs immunized with piresorf5/il-2 and one of three pigs immunized with piresorf7/il-2 were protected from lung lesio ... | 2004 | 15507312 |
| cytokines and synthetic double-stranded rna augment the t helper 1 immune response of swine to porcine reproductive and respiratory syndrome virus. | immunization of pigs with a modified live porcine reproductive and respiratory syndrome virus (prrsv) vaccine initially elicits a weak interferon (ifn)-gamma response. to improve the immune response, an adjuvant consisting of plasmid encoding either porcine interleukin (il)-12 or ifn-alpha was co-administered during vaccination. in the presence of either adjuvant, at least a three-fold increase in the primary virus-specific ifn-gamma response was observed. while this enhancement was only transie ... | 2004 | 15507313 |
| beta-glucan enhancement of t cell ifngamma response in swine. | beta-glucan has been shown to enhance anti-tumor and anti-infection functions in animals. pigs at 4 months of age were infected with porcine reproductive and respiratory syndrome virus (prrsv), and peripheral blood monocytes (pbmc) were isolated for the detection of interferon gamma (ifngamma)-producing cells. we found that soluble high molecular weight beta-glucan could increase ifngamma-producing cell frequency in a dose-dependent manner in the enzyme-linked immunospot assay (elispot) in the a ... | 2004 | 15507314 |
| humoral immune response induced by oral administration of s. typhimurium containing a dna vaccine against porcine reproductive and respiratory syndrome virus. | the orfs-encoded major envelope glycoprotein (gp5) of porcine reproductive and respiratory syndrome virus (prrsv) is one of the major structural proteins of this virus. in this report, we described the induction of a prrsv gp5-specific immune response by oral vaccination of mice with eukaryotic expression vectors containing the gp5 gene of prrsv (pcdna3-gp5), delived by attenuated salmonella typhimurium aroa. it demonstrated that oral administration of the transformants resulted in expression of ... | 2004 | 15507315 |
| oral immunization induces local and distant mucosal immunity in swine. | transmission of porcine reproductive and respiratory syndrome virus (prrsv) in semen and reproductive disease in pregnant swine might be reduced by vaccines that induce mucosal immunity in the reproductive tract. cholera toxin (ct), when delivered orally, is a potent mucosal adjuvant and immunogen in swine. to determine if oral immunization additionally elicits immunity at distant mucosal surfaces, we examined antibody responses to ct-b subunit in the reproductive tract and oral cavity. orally a ... | 2004 | 15507316 |
| encephalomalacic lesions in pigs dually infected with porcine reproductive and respiratory syndrome virus and pseudorabies virus. | four pigs (group 1) were infected with an aerosol containing porcine reproductive and respiratory syndrome virus (prrsv) followed 7 days later by pseudorabies virus (prv). three further pigs (group 2) received prrsv alone, two (group 3) received prv alone, and two (group 4) remained as uninfected controls. despite the admittedly small numbers of animals, the experiment appeared to throw light on aspects of synergy. thus, the group 1 pigs showed severe neurological signs characterized by ataxia a ... | 2004 | 15511536 |
| decreased protein accretion in pigs with viral and bacterial pneumonia is associated with increased myostatin expression in muscle. | chronic respiratory infections reduce growth in pigs but protein accretion (pa) during an ongoing multifactorial respiratory infection has not been determined, and the mechanisms underlying growth inhibition are largely unknown. the objectives of this study were to determine whether viral and bacterial pneumonia in young pigs decrease pa, increase serum il-1beta and il-6, and increase myostatin (mstn) mrna in biceps femoris and triceps muscles. mycoplasma hyopneumoniae (mh) or medium was given i ... | 2004 | 15514274 |
| significance of the oligosaccharides of the porcine reproductive and respiratory syndrome virus glycoproteins gp2a and gp5 for infectious virus production. | the arterivirus porcine reproductive and respiratory syndrome virus (prrsv) contains four glycoproteins, gp(2a), gp(3), gp(4) and gp(5), the functions of which are still largely unresolved. in this study, the significance of the n-glycosylation of the gp(2a) and gp(5) proteins of prrsv strain lv was investigated. both glycoproteins contain two predicted n-glycosylation sites that are highly conserved between north american-type and european-type prrsv. using site-directed mutagenesis, single and ... | 2004 | 15557245 |
| replication kinetics of different porcine circovirus 2 strains in pk-15 cells, fetal cardiomyocytes and macrophages. | in this in vitro study, the replication kinetics of porcine circovirus type 2 (pcv2) in porcine alveolar macrophages (pam) and fetal cardiomyocytes (fcm), two target cells in vivo, was compared with that in pk-15 cells. cultures were inoculated with either the postweaning multisystemic wasting syndrome (pmws)-associated strain stoon-1010 or the abortion-associated strain 1121. viral proteins were visualized and virus production was determined. in pk-15 cells, the capsid protein was expressed bet ... | 2004 | 15578238 |
| evaluation of the presence of porcine reproductive and respiratory syndrome virus in pig meat and experimental transmission following oral exposure. | a study was performed to evaluate the presence of porcine reproductive and respiratory syndrome virus (prrsv) in pig meat collected at slaughterhouses and its potential transmission to pigs via pig meat. a total of 1039 blood samples were collected from pigs upon their arrival at the abattoir. the following day, meat samples (n = 1027) were collected from the carcasses of these same pigs. samples originated from 2 canadian slaughterhouses, 1 situated in the province of quebec and the other situa ... | 2004 | 15581220 |
| virological and immunological responses to porcine reproductive and respiratory syndrome virus in a large population of gilts. | porcine reproductive and respiratory syndrome virus (prrsv) causes a prolonged active infection followed by a persistent infection in lymphoid tissues lasting for several months. pigs develop both an antibody and cell-mediated immune response following prrsv infection, but the specific role of each type in the development of protective immunity and clearance of the virus is not yet known. the aims of this study were to characterize the dynamics of prrsv persistence from 0 to 135 d post infection ... | 2004 | 15581221 |
| a dna-launched reverse genetics system for porcine reproductive and respiratory syndrome virus reveals that homodimerization of the nucleocapsid protein is essential for virus infectivity. | reverse genetic systems were developed for a highly virulent 'atypical' porcine reproductive and respiratory syndrome virus (prrsv). the full-length genome of 15395 nucleotides was assembled as a single cdna clone and placed under either the prokaryotic t7 or eukaryotic cmv promoter. transfection of cells with the rna transcripts or the dna clone induced cytopathic effects and produced infectious progeny. the reconstituted virus was stable and grew to the titer of the parental virus in cells. up ... | 2005 | 15582652 |
| porcine reproductive and respiratory syndrome virus infection in the boar: a review. | porcine reproductive and respiratory syndrome (prrs) is caused by prrs virus, which, like other members of the arterividae family, has the ability to infect macrophages and to persist in tissues for at least several months after the acute stage of infection subsides. as a consequence, prrs has a complex epidemiologic profile and has been especially difficult to control under the usual conditions of commercial swine production. although vaccines are commonly used, vaccination is only one of sever ... | 2005 | 15589269 |
| [well attended symposium about prrs and haemophilus infection]. | 2004 | 15622898 | |
| viruses in boar semen: detection and clinical as well as epidemiological consequences regarding disease transmission by artificial insemination. | many viruses have been reported to be present in boar semen, particularly during the viremic phase of the diseases. some of them, such foot-and-mouth disease virus, porcine reproductive and respiratory syndrome virus, swine vesicular disease virus, porcine parvovirus, picornaviruses, adenoviruses, enteroviruses, japanese encephalitis virus, pseudorabies virus, african swine fever virus and reoviruses are of particular importance and accurate monitoring prior to and during the presence of boars i ... | 2005 | 15626416 |
| the origin and evolution of porcine reproductive and respiratory syndrome viruses. | porcine reproductive and respiratory syndrome viruses (prrsv) are divided into north american and european types, which show about 40% difference in their amino acid sequences. the divergence time of these two types has been estimated to be about 1980 from epidemiological data. this suggested that prrsv have evolved at a higher evolutionary rate (order of 10(-2)/site/year) compared with other rna viruses of 10(-3) to 10(-5)/site/year. here, to test the evolutionary history of prrsv speculated by ... | 2005 | 15659555 |
| epitope specificity of monoclonal antibodies to the n-protein of porcine reproductive and respiratory syndrome virus determined by elisa with synthetic peptides. | in an attempt to develop an alternate to elisas using recombinant n-proteins as antigen for the sero-diagnosis of porcine reproductive and respiratory syndrome virus (prrsv) infections of pigs i have measured the binding of nine anti-n-protein mabs, which had been previously generated by various investigators, to overlapping peptides encompassing amino acids 19-70 of the n-proteins of the north american prototype (vr2332) and the european prototype (lelystad virus, lv) of prrsv. i also measured ... | 2005 | 15661331 |
| cloning and expression of interferon-alpha/gamma from a domestic porcine breed and its effect on classical swine fever virus. | to further evaluate the clinical impact of recombinant poifn-alpha/gamma, poifn-alpha/gamma genes from a chinese domestic big-white porcine breed were cloned using pcr, and expressed in a high-level prokaryotic system. the antiviral activities of rpoifn-alpha/gamma on vesicular stomatitis virus (vsv), porcine reproductive and respiratory syndrome virus (prrsv), and classical swine fever virus (csfv) were investigated in different cell lines. the cloned poifn-alpha gene encodes a protein of 166 a ... | 2005 | 15661333 |
| real-time pcr for quantitation of porcine reproductive and respiratory syndrome virus and porcine circovirus type 2 in naturally-infected and challenged pigs. | real-time pcr assays were developed for quantitative detection of porcine reproductive and respiratory syndrome virus (prrsv) and porcine circovirus type 2 (pcv2). the established real-time pcr for the quantitation of prrsv cdna and pcv2 dna were found to be in the 9-log(10) linear dynamic range with excellent linearity and reliable reproducibility. using these techniques, the distribution and quantitation of prrsv and pcv2 in naturally infected and challenged pigs were investigated. the viral c ... | 2004 | 15664045 |
| cellular immune responses in the lungs of pigs infected in utero with prrsv: an immunohistochemical study. | the cellular response in the lungs of pigs transplacentally infected with porcine reproductive and respiratory syndrome virus (prrsv) was examined by immunohistochemistry. double staining for the t-cell marker antigen cd3 and prrsv demonstrated that the appearance and distribution of t-cells homing to the lungs of infected pigs correlated well with the presence and location of virusinfected cells. single stainings showed that cells positive for the cd2 and cd8 antigen were almost as numerous in ... | 2004 | 15671752 |
| temporary cd8+ t-cell depletion in pigs does not exacerbate infection with porcine reproductive and respiratory syndrome virus (prrsv). | several studies have demonstrated a consistent increase in the cd8+ t-cell subset of pigs following infection with porcine reproductive and respiratory virus (prrsv). consequently, it has been suggested that cd8+ t-cells may play an important role in protection against this infection. in order to test this hypothesis, we examined five 5-week-old pigs, which had been depleted for cd8+ t-cells by treatment with anti-cd8 mab injections, starting 2 days before inoculation with prrsv. virus-inoculate ... | 2004 | 15671757 |
| survival and infectivity of porcine reproductive and respiratory syndrome virus in swine lagoon effluent. | 2005 | 15675529 | |
| an evaluation of thermo-assisted drying and decontamination for the elimination of porcine reproductive and respiratory syndrome virus from contaminated livestock transport vehicles. | the purpose of this report is to validate a new protocol, the thermo-assisted drying and decontamination (tadd) system, for eliminating porcine reproductive and respiratory syndrome virus (prrsv) from contaminated transport vehicles. scale models of weaned pig trailers were used. the principle of tadd is to raise the interior temperature of trailers to 71 degrees c for 30 min to promote drying and degradation of prrsv. trailer interiors were artificially contaminated with 5 x 10(5) tcid50 of prr ... | 2005 | 15745224 |
| an evaluation of disinfectants for the sanitation of porcine reproductive and respiratory syndrome virus-contaminated transport vehicles at cold temperatures. | the objective of this study was to evaluate the efficacy of commercially available disinfectants to sanitize porcine reproductive and respiratory syndrome virus (prrsv) contaminated trailer models in cold climates (-20 degrees c and 4 degrees c). disinfectants evaluated included synergize, aseptol 2000, biophene, sentramax, virkon, tek trol, and dc&r. all products were applied to trailers via fumigation at 4 degrees c. following experimental contamination of model trailers with prrsv mn 30-100 ( ... | 2005 | 15745225 |
| eradication of porcine reproductive and respiratory syndrome virus by serum inoculation of naïve gilts. | the acclimatization program included exposure to serum and recovery. a continuous flow unit (nursery to finishing) from the same farm was selected as a potential source of porcine reproductive and respiratory syndrome virus (prrsv). negative gilts were inoculated 5 d after arrival by intramuscular injection of serum from selected animals. there was a significant reduction in seroprevalence in the sow herd 1 y after implementation of the gilt inoculation program (p < 0.05). at that time, all of t ... | 2005 | 15745226 |
| new insights into the genetic diversity of european porcine reproductive and respiratory syndrome virus (prrsv). | the complete orf5 sequences of 66 porcine reproductive and respiratory syndrome (prrs) field virus strains (1991-2001) and three european modified live vaccine strains were determined, as well as orfs 6 and 7 of 19 selected strains. the variability of the deduced orf5 amino acid sequences was analysed using statistical process control (spc), allowing for the objective assessment of variable and conserved regions. four variable and four conserved regions as well as five hypervariable amino acid p ... | 2005 | 15795076 |
| porcine reproductive and respiratory syndrome virus infection increases cd14 expression and lipopolysaccharide-binding protein in the lungs of pigs. | porcine reproductive and respiratory syndrome virus (prrsv) is a respiratory virus of swine that plays an important role in multifactorial respiratory disease. european strains of prrsv cause mild or no respiratory signs on their own, but can sensitize the lungs for the production of proinflammatory cytokines and respiratory signs upon exposure to bacterial lipopolysaccharides (lps). the inflammatory effect of lps depends on the binding to the lps receptor complex. therefore, we quantified the l ... | 2005 | 15802956 |
| polyclonal hypergammaglobulinemia and formation of hydrophobic immune complexes in porcine reproductive and respiratory syndrome virus-infected and uninfected pigs. | infection of young conventional, domestic pigs with porcine reproductive and respiratory syndrome virus (prrsv) strains vr2332 and ja142 resulted in a rapid, progressive increase in serum igg reaching maximum levels of 20-30 mg/ml at about 3 weeks post infection (p.i.), which were maintained until at least 63 days p.i., whereas the level of serum igg remained at 4-6 mg/ml in sham infected pigs. in most of the vr2332 and ja142-infected pigs hypergammaglobulimenia was associated with the formation ... | 2005 | 15802958 |
| simultaneous detection of north american and european porcine reproductive and respiratory syndrome virus using real-time quantitative reverse transcriptase-pcr. | porcine reproductive and respiratory syndrome (prrs) is 1 of the most economically important diseases of swine. detection of the etiologic agent, prrs virus (prrsv), represents a diagnostic challenge due to the heterogeneity of field isolates as well as the propensity for swine to develop persistent infection in which virus is difficult to detect. recently european (eu) lineage prrsv isolates, which are genetically divergent from north american (na) isolates, have been introduced into na swine f ... | 2005 | 15825498 |
| analysis of porcine reproductive and respiratory syndrome virus attachment and internalization: distinctive roles for heparan sulphate and sialoadhesin. | heparan sulphate and sialoadhesin were previously identified on porcine macrophages as receptors for porcine reproductive and respiratory syndrome virus (prrsv). in this study, the exact role and cooperation of heparan sulphate and sialoadhesin during prrsv attachment and internalization was analysed. it was observed that both heparan sulphate and sialoadhesin mediate prrsv attachment and that only these two receptors are involved in attachment. analysis of attachment kinetics of prrsv to macrop ... | 2005 | 15831956 |
| laboratory model to evaluate the role of aerosols in the transport of porcine reproductive and respiratory syndrome virus. | the aim of this study was to develop a model to evaluate the aerosol transmission of porcine reproductive and respiratory disease virus (prrsv). prrsv (mn 30-100 strain, total dose 3 x 10(6) virus particles) was aerosolised and transported up to 150 m and a portable air sampler was used to collect air samples at 1, 30, 60, 90, 120 and 150 m (five replicates at each distance) and the air samples were tested by taqman pcr and virus isolation. the infectivity of the aerosolised prrsv was tested by ... | 2005 | 15833966 |
| the use of endogenous and exogenous reference rnas for qualitative and quantitative detection of prrsv in porcine semen. | semen is known to be a route of porcine reproductive and respiratory syndrome virus (prrsv) transmission. a method was developed for qualitative and quantitative detection of the seminal cell-associated prrsv rna in relation to endogenous and exogenous reference rnas. as endogenous control for one-step real-time reverse transcription (rt)-pcr ube2d2 mrna was selected. particularly for the analysis of persistent infections associated with low copy numbers of prrsv rna, ube2d2 mrna is an ideal con ... | 2005 | 15847915 |
| identification of viral pathogens in aborted fetuses and stillborn piglets from cases of swine reproductive failure in spain. | the objective of the present study was to determine the presence of recognised abortifacient viruses such as porcine reproductive and respiratory virus (prrsv), aujeszky's disease virus (adv), porcine parvovirus (ppv) and porcine circovirus type 2 (pcv2), in tissues from aborted fetuses and stillborn neonates in cases of late reproductive failure in swine. a total of 293 specimens (fetuses aborted in the last third of gestation and stillborn piglets) from 100 different cases of late-term abortio ... | 2005 | 15848788 |
| genetic variability of prrs virus in austria: consequences for molecular diagnostics and viral quantification. | porcine reproductive and respiratory syndrome virus is a virus with a relatively high level of sequence variation, especially between the european and the american-type strains. this high degree of sequence variations will influence the accuracy of results obtained by molecular diagnostic methods, especially if mutations are located in the primer or probe binding regions of pcr or real-time pcr based assays. in order to provide the basis for the development of an accurate, region-tailored assay ... | 2005 | 15863276 |
| prrsv planned exposure and the law. | 2005 | 15881989 | |
| alternative codon usage of prrs virus orf5 gene increases eucaryotic expression of gp(5) glycoprotein and improves immune response in challenged pigs. | pigs exposed to gp(5) protein of prrsv by means of dna immunization develop specific neutralizing and protecting antibodies. herein, we report on the consequences of codon bias, and on the favorable outcome of the systematic replacement of native codons of prrsv orf5 gene with codons chosen to reflect more closely the codon preference of highly expressed mammalian genes. therefore, a synthetic prrsv orf5 gene (synorf5) was constructed in which 134 nucleotide substitutions were made in comparison ... | 2005 | 15893859 |
| correlation of cell-mediated immunity against porcine reproductive and respiratory syndrome virus with protection against reproductive failure in sows during outbreaks of porcine reproductive and respiratory syndrome in commercial herds. | to determine whether cell-mediated immunity against porcine reproductive and respiratory syndrome (prrs) virus is correlated with protection against reproductive failure in sows during clinical outbreaks of prrs in commercial herds. | 2005 | 15906573 |
| evaluation of virus decontamination techniques for porcine embryos produced in vitro. | the objective of this study was to explore approaches to decontaminate embryos either contaminated naturally or under experimental conditions with different viruses. embryos were obtained from in vitro maturation and fertilisation of porcine oocytes. after 7 days of development, morula and blastocyst stages were exposed for 1 h to the following viruses: encephalomyocarditis virus (emcv), porcine circovirus type 2 (pcv2), porcine parvovirus (ppv), porcine reproductive and respiratory syndrome vir ... | 2005 | 15910918 |
| genetic variation and geographic distribution of porcine reproductive and respiratory syndrome virus in japan. | porcine reproductive and respiratory syndrome virus (prrsv) has two genotypes, the north american-type (na-type) and the european-type (eu-type), and each genotype is also genetically diverged. we sequenced the orf5 gene of 30 prrsvs isolated from 23 prefectures of japan during 1992 and 1993 and during 2000 and 2001. all of the isolates were of the na-type. phylogenetic analysis of the overall na-type viruses isolated from around the world identified five major genetic clusters. the 1992-1993 ja ... | 2005 | 15931465 |
| interleukin-12 (il-12) ameliorates the effects of porcine respiratory and reproductive syndrome virus (prrsv) infection. | porcine respiratory and reproductive syndrome virus (prrsv) disease, one of the most economically significant viral diseases in the swine industry, is characterized by miscarriages, premature farrowing, stillborn pigs, and respiratory disease associated with death and chronic poor performance of nursing and weaned pigs. interleukin-12 (il-12) is a key component in driving the development of cell-mediated immunity as well as stimulating interferon-gamma (ifn-gamma) production from t cells and nat ... | 2005 | 15936827 |
| reduction of porcine reproductive and respiratory syndrome virus (prrsv) infection in swine alveolar macrophages by porcine circovirus 2 (pcv2)-induced interferon-alpha. | two common viral pathogens of swine, namely, porcine circovirus type 2 (pcv2) and porcine reproductive and respiratory syndrome virus (prrsv), were investigated in regard to their effects on monolayer cultures of swine alveolar macrophages (ams). the purpose was to identify selected cellular changes and responses potentially associated with the clinical reactions of pigs infected with either or both of these viruses. measurements included the (1) absolute and relative numbers of infected, viable ... | 2005 | 15936905 |
| biological responses to porcine respiratory and reproductive syndrome virus in pigs of two genetic populations. | one hundred pigs from the ne index line (nei) and 100 hampshire-duroc cross pigs (hd) were inoculated intranasally with porcine respiratory and reproductive syndrome virus (prrsv 97-7895 strain) at 26 d of age to determine whether genetic variation in response to prrsv exists. an uninfected littermate to each infected pig served as a control. pigs were from 163 dams and 83 sires. body weight and rectal temperature were recorded, and blood samples were drawn from each pig on d 0 before inoculatio ... | 2005 | 15956456 |
| porcine reproductive and respiratory syndrome (prrs) virus--a significant disease of pigs. | 2005 | 15957382 | |
| immune responses of pigs after experimental infection with a european strain of porcine reproductive and respiratory syndrome virus. | the purpose of this experiment was to study the immune response of pigs during an experimental infection with a european strain of porcine reproductive and respiratory syndrome virus (prrsv). five pigs were challenged intranasally with prrsv strain vp21 and another five were kept as controls. clinical course and humoral and cell-mediated responses were monitored for 70 days post-infection (p.i.). infected pigs developed mild signs at 24 h p.i. viraemia was detectable by nested rt-pcr until day 1 ... | 2005 | 15958672 |
| protective immunity induced by a recombinant pseudorabies virus expressing the gp5 of porcine reproductive and respiratory syndrome virus in piglets. | pseudorabies virus (prv) has been developed as a vaccine vector for expressing foreign immunogens. porcine reproductive and respiratory syndrome (prrs), caused by porcine reproductive and respiratory syndrome virus (prrsv), continues to be a major problem to the pork industry worldwide. many vaccine strategies have been developed to control the disease but most of them turn out to be unsuccessful. the objective of this research was to explore the feasibility of prv-based vector vaccine in protec ... | 2005 | 15963827 |
| identification of a novel b cell epitope on the nucleocapsid protein of porcine reproductive and respiratory syndrome virus by phage display. | a phage display peptide library targeting the nucleocapsid (n) protein of porcine reproductive and respiratory syndrome virus (prrsv) strain ch-1a was generated and used for epitope mapping. after 3 rounds of biopanning with the monoclonal antibody (mab) n3h2 directed against the n protein, 3 positive phages were screened and sequenced. these phages share a consensus sequence, iqtafnqga, which corresponds to the amino acid (aa) 79-87 segment of the ch-1a n protein. a small dna fragment coding fo ... | 2005 | 15965612 |
| [pcr detection of pcv-2 and prrsv in porcine pleuropneumonia samples]. | pcv-2 (porcine circovirus type-2, pcv-2) and prrsv (porcine reproductive and respiratory syndrome virus, prrsv) were detected by pcr from 253 porcine pleuropneumonia samples and 125 clinically healthy lung samples were collected from different districts of shandong province. the results showed that 171 samples for pcv-2 and 101 samples for prrsv were positive. the positive ratio were 67.5% and 40%, respectively. the co-infection number of pcv-2 and prrsv was 68 in 253 samples, the positive ratio ... | 2005 | 15989234 |
| discriminating between serological responses to european-genotype live vaccine and european-genotype field strains of porcine reproductive and respiratory syndrome virus (prrsv) by peptide elisa. | a peptide elisa was developed based on an immunodominant and hypervariable epitope in the orf4 envelope glycoprotein of porcine reproductive and respiratory syndrome virus (prrsv). the peptide sequence was derived from the porcilis live-attenuated prrsv vaccine strain (genotype 1, european). antibodies induced by the field prrsvs currently circulating in poland were not detected by the porcilis orf4 peptide elisa. in contrast, porcilis-vaccinated animals seroconverted in the orf4 peptide elisa a ... | 2005 | 15992937 |
| divergence time of porcine reproductive and respiratory syndrome virus subtypes. | porcine reproductive and respiratory syndrome virus (prrsv) recently emerged in domestic pigs of western europe and north america. although time of emergence was identical on the two continents, genetic composition was markedly different with a clear geographical subtype structure, indicating that subtypes diverged in separate reservoirs prior to emergence. genetic analyses have shown that the most recent common ancestor (mrca) of western european isolates existed around 1980 and that these orig ... | 2005 | 16000650 |
| [expression of gp5-m fusion protein of porcine reproductive and respiratory syndrone virus (prrsv) and establishment of elisa diagnose based on the recombinant fusion protein]. | the cdna fragment encoding the truncated gp5 and the full-length m protein of porcine reproductive and respiratory syndrone virus (prrsv) were orderly fused to the downstream of glutathione s-transferase (gst) of pgex-kg expression vector, resulting in the fusion expression plasmid pkg-56. after transformed into e. coli bl21 (de3) and induced by iptg, the results of sds-page showed that the gst-gp5-m fusion protein was expressed in high level. western-blot was performed to confirm that the expre ... | 2005 | 16013486 |
| efficacy of spray-drying to reduce infectivity of pseudorabies and porcine reproductive and respiratory syndrome (prrs) viruses and seroconversion in pigs fed diets containing spray-dried animal plasma. | three experiments were conducted to evaluate viral inactivation by the spray-drying process used in the production of spray-dried animal plasma (sdap). in exp. 1, bovine plasma was inoculated with pseudorabies virus (prv) grown in pk 15 cells. three 4-l batches were spray-dried in the same manner and conditions of industrial sdap production but with laboratory spray-drying equipment. presence of infectivity was determined before and after spray-drying by microtiter assay in pk 15 cell cultures. ... | 2005 | 16024714 |
| porcine reproductive and respiratory syndrome (prrs) virus-specific interferon-gamma(+) t-cell responses after prrs virus infection or vaccination with an inactivated prrs vaccine. | although field studies have found porcine reproductive and respiratory syndrome (prrsv) inactivated vaccines to be beneficial in reducing losses linked to prrsv infection, immune mechanisms induced by these vaccines need better understanding. in the study reported here, we examined the interferon-gamma(+) (ifngamma(+)) prrs-specific t cell responses induced after infection and vaccination with an inactivated prrs vaccine. autologous monocyte-derived dendritic cells loaded with the prrsv p120 str ... | 2005 | 16035950 |
| evaluation of the aerosol transmission of a mixed infection of mycoplasma hyopneumoniae and porcine reproductive and respiratory syndrome virus. | to evaluate the transmission of mycoplasma hyopneumoniae and porcine reproductive and respiratory syndrome virus (prrsv) by aerosol as either a single or mixed infection, 28 pigs were inoculated intratracheally with m hyopneumoniae on day 0 and infected intranasally with prrsv on day 35; they were housed together in a barn. to assess the aerosol transmission of m hyopneumoniae as a single infection, one trailer (a) containing 10 five-week-old sentinel pigs was placed along the south side of the ... | 2005 | 16040942 |
| seroprevalence of six reproductive pathogens in european wild boar (sus scrofa) from spain: the effect on wild boar female reproductive performance. | we studied the seroprevalence of six reproductive pathogens in spanish hunter-harvested wild boar females. the sample was representative of the hunting harvest in the studied hunting estates. mean antibody prevalences were: 60.6+/-0.06% for aujeszky's disease virus (adv), 56.6+/-0.09% for porcine parvovirus (ppv), 51.8+/-0.06% for porcine circovirus type 2 (pcv2), 29.7+/-0.09% for brucella spp. and 36.3+/-0.1% for toxoplasma gondii. we did not detect antibodies against porcine reproductive and r ... | 2006 | 16076482 |
| the 2b protein as a minor structural component of prrsv. | porcine reproductive and respiratory syndrome virus (prrsv) orf2 contains an internal orf that codes for a small non-glycosylated protein known as 2b. previous work had identified the presence of a 10kda 2b protein in virus-infected cells and the induction of an anti-2b response in prrsv-infected pigs, as well as a possible association of 2b with the virion (, virology 287:183-191). in this study, we utilized two experimental approaches, including the use of a 2b peptide-specific monoclonal anti ... | 2005 | 16095746 |
| the adjuvant effect of levamisole on killed viral vaccines. | to explore adjuvants that are capable of promoting th1-biased immune response, we investigated the usefulness of levamisole (lms) as one such adjuvant for two different preparations of killed viral vaccines, derived from the foot mouth disease virus (fmdv) or the porcine respiratory reproductive syndrome virus (prrsv) and tested respectively in balb/c or c57 bl/6 mice. the results showed that lms induced different types of immune responses in the host, depending on its dosage. while a high level ... | 2005 | 16095767 |
| probability of porcine reproductive and respiratory syndrome (prrs) virus infection as a function of exposure route and dose. | at the most elemental level, the design of effective strategies to control and/or eliminate porcine reproductive and respiratory syndrome (prrs) virus depend on an accurate and comprehensive understanding of virus transmission. as a general rule, transmission is highly dependent on the route of exposure and the dose of virus. the objective of this study was to derive prrs virus isolate vr-2332 dose-response curves for oral and intranasal routes of exposure, i.e., determine the probability that a ... | 2005 | 16098692 |
| [purification and structural analysis of the nucleocapsid of prrs virus expressed from escherichia coli]. | the dna fragment encoding the nucleocapsid protein (n) of prrsv bj4 strain were cloned into the bamh i / ecor i sites of pet28a vector to construct the expression plasmid pet28-n by designing special primers. the soluble protein (p28-n) were obtained by introducing the expression plasmid into e. coli bl21 (de3) host cell, and the amount of recombinant protein reached to 28% of the total mass of bacterial protein. pet28-n were purified by nickel-affinity column of proband resin. the circular dich ... | 2004 | 16110950 |
| occurrence of salmonella serotype typhimurium dt104 on a commercial swine farm before, during, and after depopulation and repopulation. | to determine whether depopulation-repopulation could be used to eradicate salmonella serotype typhimurium dt104 from a commercial swine farm in the midwestern united states. | 2005 | 16121615 |
| porcine arterivirus activates the nf-kappab pathway through ikappab degradation. | nuclear factor-kappab (nf-kappab) is a critical regulator of innate and adaptive immune function as well as cell proliferation and survival. the present study demonstrated for the first time that a virus belonging to the arteriviridae family activates nf-kappab in marc-145 cells and alveolar macrophages. in porcine reproductive and respiratory syndrome virus (prrsv)-infected cells, nf-kappab activation was characterized by translocation of nf-kappab from the cytoplasm to the nucleus, increased d ... | 2005 | 16129468 |
| envelope protein requirements for the assembly of infectious virions of porcine reproductive and respiratory syndrome virus. | virions of porcine reproductive and respiratory syndrome virus (prrsv) contain six membrane proteins: the major proteins gp5 and m and the minor proteins gp2a, e, gp3, and gp4. here, we studied the envelope protein requirements for prrsv particle formation and infectivity using full-length cdna clones in which the genes encoding the membrane proteins were disrupted by site-directed mutagenesis. by transfection of rnas transcribed from these cdnas into bhk-21 cells and analysis of the culture med ... | 2005 | 16160177 |
| positive inductive effect of il-2 on virus-specific cellular responses elicited by a prrsv-orf7 dna vaccine in swine. | this study investigated the effect of swine interleukin 2 (il-2) and swine interleukin 4 (il-4) on the development of immune responses induced by a prrsv-orf7 dna vaccine (phcmv-orf7). the two cytokines were cloned separately in the eukaryotic expression vector phcmv, and delivered via gene gun as adjuvants for the dna vaccine. groups of 3-week-old certified prrsv-free, castrated male, yorkshire crossbred pigs, were vaccinated with or without the il-2 or il-4. the ensuing humoral and cellular im ... | 2006 | 16162362 |
| immune responses and protection by vaccine and various vaccine adjuvant candidates to virulent porcine reproductive and respiratory syndrome virus. | various vaccine adjuvant candidates were assessed with the modified-live porcine reproductive and respiratory syndrome virus (mlv prrsv) (ingelvac prrs mlv) vaccine. their influence on humoral-mediated immune (hmi) and cell-mediated immune (cmi) responses as well as protection from virulent prrsv challenge (mn-184) was evaluated. ninety seronegative pigs were randomly divided into nine groups of 10 pigs. one group received mlv vaccine alone. five groups received mlv vaccine with either bacterial ... | 2006 | 16165219 |
| effects of two commercial european modified-live vaccines against porcine reproductive and respiratory syndrome viruses in pregnant gilts. | the purpose of this study was to assess the effects of two currently available commercial european-type modified-live virus (mlv) vaccines against porcine reproductive and respiratory syndrome in a reproductive pig model. sixteen 90-day pregnant gilts were divided into four groups and allocated to one of the following intranasal treatments: group a gilts served as negative controls; group b gilts were exposed to a virulent european field strain; group c gilts were exposed to vaccine strain vp046 ... | 2006 | 16169756 |
| gammadelta lymphocyte response to porcine reproductive and respiratory syndrome virus. | porcine reproductive and respiratory syndrome virus (prrsv) continues to be one of the most important diseases facing swine industry today. following prrsv infection pigs develop both humoral and cell-mediated responses following prrsv exposure; however, the relative importance in protection and clearance of the virus is not yet completely understood. swine contain a large percentage of gammadelta t-lymphocytes in peripheral circulation capable of responding to various pathogens in both an innat ... | 2005 | 16212527 |
| in vitro susceptibility of macrophages to porcine reproductive and respiratory syndrome virus varies between genetically diverse lines of pigs. | porcine reproductive and respiratory syndrome virus (prrsv) continues to be responsible for financial losses in the swine industry worldwide. it remains undetermined whether genetic variability of the host in susceptibility to prrsv exists and if this variability can be exploited to help control this important disease. the objective of this study was to determine if an in vitro flow cytometry (facs) assay that detects the percentage of monocyte-derived macrophages (mdm) infected with prrsv could ... | 2005 | 16212529 |
| the dimer interface of the sars coronavirus nucleocapsid protein adapts a porcine respiratory and reproductive syndrome virus-like structure. | we have employed nmr to investigate the structure of sars coronavirus nucleocapsid protein dimer. we found that the secondary structure of the dimerization domain consists of five alpha helices and a beta-hairpin. the dimer interface consists of a continuous four-stranded beta-sheet superposed by two long alpha helices, reminiscent of that found in the nucleocapsid protein of porcine respiratory and reproductive syndrome virus. extensive hydrogen bond formation between the two hairpins and hydro ... | 2005 | 16214138 |
| cysteine residues of the porcine reproductive and respiratory syndrome virus small envelope protein are non-essential for virus infectivity. | porcine reproductive and respiratory syndrome virus (prrsv) open reading frame (orf) 2a contains a small internal orf (2b) capable of encoding a protein of 73 aa, termed e protein. the function of e protein is currently unknown. the e protein possesses two cysteines at positions 49 and 54 that are highly conserved among north american isolates. in the present study, it was shown that e protein did not homodimerize with itself nor did it heterodimerize with the nucleocapsid (n) protein. however, ... | 2005 | 16227232 |
| [prevalence and association of porcine circovirus type 2 (pcv2), porcine parvovirus (ppv) and porcine reproductive and respiratory syndrome virus (prrsv) in aborted fetuses, mummified fetuses, stillborn and nonviable neonatal piglets]. | porcine circovirus type 2 (pcv2) seems to cause reproductive failure in sows not only in experimental studies. a retrospective study was made with a total of 252 aborted fetuses, mummified fetuses, stillborn and nonviable neonatal piglets to determine the presence of pcv2, porcine parvovirus (ppv) and porcine respiratory and reproductive syndrome virus (prrsv) by pcr. pcv2 was found in all stages of gestation in 27.1 percent of samples examined. a statistically significant association could be s ... | 2005 | 16240914 |
| study on the virulence, cell-mediated immune response and histolesivity of three field prrsv strains with an orf 5 genetic variation. | 2005 | 16244965 | |
| retention of ingested porcine reproductive and respiratory syndrome virus in houseflies. | to evaluate retention of porcine reproductive and respiratory syndrome virus (prrsv) in houseflies for various time frames and temperatures. | 2005 | 16261824 |
| evolution of orf5 of spanish porcine reproductive and respiratory syndrome virus strains from 1991 to 2005. | orf5 sequences of porcine reproductive and respiratory syndrome virus (prrsv) were analysed to determine genetic diversity, codon usage, positive and negative selection sites and potential changes in the predicted glycoprotein 5 (gp5). a hypothetical gp5 containing all selected sites was constructed to determine its characteristics. these sequences corresponded to isolates obtained 10 years apart (1991-1995, 18 strains) and a second set (n = 46) from 2000 to 2005. similarity to lelystad virus (l ... | 2006 | 16269197 |
| [fusion expression of the orf5 gene of porcine reproductive and respiratory syndrome virus in insect cells]. | a 0.75kb fragment containing the complete cdna of glutathione-s-transferase (gst) and a modified thrombin cleavage sites were amplified and cloned into pfastbacl, the donor plasmid of bac-to-bac baculovirus expression systems, downstream from the polyhedrin promoter (ppolh), resulting in the gst fusion transposition plasmid pfgst. after transposition and transfection, sds-page analysis showed that the developed gst fusion expression system can highly express gst. the signal sequences of the majo ... | 2003 | 16276865 |
| sow performance in an endemically porcine reproductive and respiratory syndrome (prrs)-infected farm after sow vaccination with an attenuated prrs vaccine. | the objective of this field study was to evaluate in an endemically porcine reproductive and respiratory syndrome (prrs) virus-infected farm the reproductive performance of sows after their vaccination with a prrs attenuated vaccine. in a farrow-to-finish pig farm with history of endemic prrs virus infection, a total of 200 gilts and sows were used. they were divided in 2 groups of 100 animals. the first group was used as untreated controls, while the animals of the second group were vaccinated ... | 2005 | 16280205 |
| [immunogenicity of dna vaccine expressing gp5 of porcine reproductive and respiratory syndrome virus fused with vp22 of bovine herpesvirus 1]. | to enhance the immuogenicity of dna vaccines expressing the gp5 protein of porcine reproductive and respiratory syndrome virus (prrsv), the tegument protein vp22 (encoded by vp22 gene) of bovine herpesvirus 1 (bhv-1), which has been demonstrated to exhibit the unusual protein transduction property, was fused to n-terminus of gp5 of dna vaccine construct pci-orf5m, resulting in pci-vp22-orf5m expressing vp22-gp5 fusion protein. the expression of vp22-gp5 fusion protein was confirmed by both indir ... | 2005 | 16285512 |
| effects of cpg odn on cd4+ and cd8+ t subpopulations in the immune response to porcine reproductive and respiratory syndrome killed virus vaccine. | cpg odn is a noval immunostimulatory reagent in this research, the effects of immunostimulatory cpg oligodeoxynucleotides (cpg odn) on cd4+ and cd8+ t lymphocytes subpopulations in the newborn piglets blood were tested at different time with porcine reproductive and respiratory syndrome killed virus vaccine (prrs vaccine) with or without cpg odn. the results suggested that, the cd4+/cd8+ ratio decreased with age in piglets inoculated with vaccine alone or gpc odn with vaccine or phosphate buffer ... | 2006 | 16289506 |
| a simple and rapid chromatographic strip test for detection of antibody to porcine reproductive and respiratory syndrome virus. | porcine reproductive and respiratory syndrome virus (prrsv) continues to be a major economic problem for swine industries worldwide despite several disease-reduction strategies such as age-segregated early weaning and all-in-all-out pig movement. routine diagnosis of prrsv is carried out by the combined use of an antibody-detecting enzyme-linked immunosorbent assay (elisa), immunofluorescence, reverse transcription-polymerase chain reaction, and virus isolation. these assays require specialized ... | 2005 | 16312241 |
| mutations within the nuclear localization signal of the porcine reproductive and respiratory syndrome virus nucleocapsid protein attenuate virus replication. | porcine reproductive and respiratory syndrome virus (prrsv) is an rna virus replicating in the cytoplasm, but the nucleocapsid (n) protein is specifically localized to the nucleus and nucleolus in virus-infected cells. a 'pat7' motif of 41-pgkk(n/s)kk has previously been identified in the n protein as the functional nuclear localization signal (nls); however, the biological consequences of n protein nuclear localization are unknown. in the present study, the role of n protein nuclear localizatio ... | 2006 | 16330065 |