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1.
In an experiment with 40 specific pathogen-free pigs aged 3 days, the distribution of a Korean isolate of porcine reproductive and respiratory syndrome virus (PRRSV) was assessed immunohistochemically and by in-situ hybridization for a period of 28 days after intranasal inoculation. The most consistent and intense labelling for PRRSV was in the lung, the virus persisting in pulmonary macrophages for at least 28 days. The middle lobe of the lung was the optimum site for the detection of PRRSV antigens and nucleic acids, and the interstitial macrophage was the main cell type in which PRRSV was identified. Other tissues and cells in which the virus was detected included macrophages and dendritic cells in the tonsil, lymph nodes, spleen and Peyer's patches, and macrophages in the hepatic sinusoids and adrenal gland. The experiment suggested that the pathogenesis of PRRSV infection may be summarized thus: initial entry of virus through tonsillar and pulmonary macrophages, followed within 3 days by viraemia and subsequent interstitial pneumonia. 相似文献
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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 and muscular tremors. Total cell numbers in the bronchoalveolar lavage fluid were increased in all PRRSV-infected pigs, and PRRSV antigen was detected in the alveolar macrophages. Total cell numbers in the cerebrospinal fluid of group 1 pigs were considerably greater than those demonstrated in group 3, but no PRV antigen was found. Pigs of groups 1 and 2 showed pulmonary lesions, characterized by interstitial pneumonia and PRRSV antigen immunolabelling. Non-suppurative encephalitis was found in five of the six pigs of groups 1 and 3. In particular, one group 1 animal had severe necrotizing encephalitis with intranuclear inclusion bodies and associated immunolabelling of PRV antigen. The other three group 1 pigs had prominent malacic lesions, with macrophages. These neuropathological findings strongly suggested that PRRSV infection in pigs enhances the severity of brain lesions caused PRV. 相似文献
4.
Four pigs were inoculated with an aerosol containing porcine reproductive and respiratory syndrome virus (PRRSV) followed 14 days later by inoculation with pseudorabies virus (PRV). The four dually infected pigs showed severe clinical signs, and one died on day 6 after infection with PRV. As demonstrated previously, the clinical disease was much more severe than that produced by either virus alone. All four dually infected pigs developed severe non-suppurative encephalitis, two had tonsillitis, two had necrotizing bronchiolitis, and one had lymphadenitis. The distribution of lesions corresponded closely with the detection of intranuclear inclusion bodies and PRV antigen. High numbers of TUNEL-positive cells detected in the thymus were associated with thymic atrophy. 相似文献
5.
The objective of this study was to compare two Korean strains of porcine reproductive and respiratory syndrome virus (PRRSV), namely a wild type (WT) strain and a vaccine-like (VL) strain, in respect of pathogenicity and viral distribution in the tissues. Both strains were of the North American genotype. Two groups of five pregnant sows were infected with either the WT or the VL strain 2 weeks before their expected farrowing date. The WT strain-inoculated sows showed abortion and premature farrowing, whereas the VL strain-inoculated sows remained clinically normal and did not farrow prematurely. Of the 18 liveborn piglets from the WT strain-inoculated sows, 14 had interstitial pneumonia. Of the 60 liveborn piglets from the VL strain-inoculated sows, only six had interstitial pneumonia. PRRSV antigen or nucleic acid was detected in 48/65 (73.8%) of stillborn and liveborn piglets from the WT strain-inoculated sows, but in only 12/64 (18.8%) of stillborn and liveborn piglets from the VL strain-inoculated sows. 相似文献
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Complete genomic characterization of a European type 1 porcine reproductive and respiratory syndrome virus isolate in Korea 总被引:1,自引:0,他引:1
Eeuri Nam Choi-Kyu Park Seong-Hee Kim Yi-Seok Joo Sang-Geon Yeo Changhee Lee 《Archives of virology》2009,154(4):629-638
Porcine reproductive and respiratory syndrome virus (PRRSV) isolates belonging to the European genotype 1 have recently emerged
in South Korea, suggesting potential problems for disease control. In the present study, we attempted to determine the complete
nucleotide sequence of the first Korean type 1 PRRSV isolate, designated KNU-07. The full-length genome of KNU-07 was found
to be 15,038 nucleotides in length, which was 60 nucleotides shorter than the type 1 prototype strain Lelystad due to a notable
60-bp deletion within the nonstructural protein 2 (NSP2). The KNU-07 genome was shown to consist of a 221-nucleotide (nt)
5′ untranslated region (UTR), a 14,703-nt protein-coding region, and a 114-nt 3′ UTR, followed by a 42-73-bp poly(A) tail.
A nucleotide sequence comparison of the KNU-07 genome with 20 complete PRRSV genomes revealed a 10.5–13.3% and 39.5–40.3%
divergence from type 1 and type 2 strains, respectively, at the genome level, indicating a high similarity to the virus strains
commonly identified as the European genotype. In order to investigate genetic variation and to understand the molecular evolution
of the type 1 isolate in Korea, extensive phylogenetic analyses were performed using the ORF5 and ORF7 nucleotide sequences
of published type 1 PRRSV isolates. The data further indicated that the newly emerging type 1 isolate KNU-07 belongs to the
recently proposed pan-European subtype 1. Taken together, the results of this study describe the genomic characterization
of the type 1 PRRSV isolated in South Korea, suggesting a recent introduction of the virus typical for this genotype that
has commonly appeared worldwide. 相似文献
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Distribution of porcine reproductive and respiratory syndrome virus in stillborn and liveborn piglets from experimentally infected sows. 总被引:2,自引:0,他引:2
Four pregnant sows were infected 3 weeks before their expected farrowing date with a Korean isolate (North American genotype) of porcine reproductive and respiratory syndrome virus (PRRSV). The distribution of virus in their stillborn and liveborn (killed 7 days after birth) offspring was assessed immunohistochemically and by in-situ hybridization. PRRSV antigen and nucleic acid were detected in lung, thymus, liver, tonsil, spleen, heart, kidney and lymph nodes from both stillborn and liveborn piglets. Positive cells typically exhibited a red (immunohistochemistry) or dark brown (in-situ hybridization) reaction product in the cytoplasm, without background staining. The most consistent labelling for PRRSV was in the thymus, tonsil and lymph nodes. The experiment suggested that, in prenatal piglets, PRRSV replicates primarily in lymphoid tissues, having gained access to them from the placenta via the bloodstream. 相似文献
10.
Real-time PCR for quantitation of porcine reproductive and respiratory syndrome virus and porcine circovirus type 2 in naturally-infected and challenged pigs 总被引:14,自引:0,他引:14
Chung WB Chan WH Chaung HC Lien Y Wu CC Huang YL 《Journal of virological methods》2005,124(1-2):11-19
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 concentrations were expressed as the mean log(10) viral DNA or cDNA copy numbers per mg or ml of tested samples. For pigs infected naturally with both viruses, the lung, spleen, tonsil and lymphoid organs had the highest viral burdens with ranges from 5.73 to 8.38 and 5.65 to 6.91 for PRRSV and PCV2, respectively. The injection of formalin-inactivated Salmonella choleraesuis emulsified in complete Freund's adjuvant 1 week before and after the inoculation of both viruses resulted in PRRSV replication enhancement 2 weeks post-challenge. However, this facilitated the clearance of PRRSV 4 weeks post-challenge. Results from this study show that the established quantitative PCR could be a useful tool when applied to vaccine development and pathogenesis studies in the future. 相似文献
11.
Neutralizing antibody responses of pigs infected with natural GP5 N-glycan mutants of porcine reproductive and respiratory syndrome virus 总被引:2,自引:0,他引:2
Faaberg KS Hocker JD Erdman MM Harris DL Nelson EA Torremorell M Plagemann PG 《Viral immunology》2006,19(2):294-304
In order to assess the effect of the N-glycans associated with the GP5 neutralization epitope of porcine reproductive and respiratory syndrome virus (PRRSV) on the neutralizing antibody (Ab) response of swine, groups of young pigs were infected with PRRSV strains differing in N-glycosylation pattern. The humoral immune response to strain VR-2332, harboring four potential N-glycan sites, was compared to that of two natural field isolates carrying mutations either abolishing the N-glycosylation site at position 44 (N44) or the two N-glycosylation sites in the hypervariable region upstream of the neutralization epitope (HV-1). The pigs were bled at intervals and their sera were assayed for neutralizing Abs by indirect and competition ELISAs using peptides containing the GP5 neutralization epitope, and selectively for infectivity neutralization of a number of PRRSV strains. In addition, viremia was monitored by quantitative RT-PCR, and anti-N-protein Ab formation was measured by HerdChek ELISA. The neutralizing Ab responses as measured by peptide ELISA varied greatly between individual pigs infected with each PRRSV strain. Some pigs generated high titers of peptide binding Abs between 7 and 28 days post infection (p.i.), whereas other pigs had not generated a response by 90 days p.i. However, the HV-1-infected pigs generated Abs to the neutralization epitope more rapidly and to a 5-10 times higher level than VR-2332-infected pigs, and the Abs neutralized the homologous HV-1 virus 10-20 times more efficiently than PRRSV strains VR-2332, N44, MN184, or SDSU73. In contrast, most N44-infected pigs generated neutralizing Abs only after 42 days p.i. and only to low levels. The results suggest that the deletions of the N-glycans or other amino acid substitutions in the GP5 ectodomains of the mutants affect the immunogenicity of the neutralization epitope and the specificity of the Abs raised to it but not the sensitivity of the virions to Ab neutralization. 相似文献
12.
Zhi Zhou Qi Liu Dongmei Hu Qian Zhang Tao Han Ying Ma Xiaoxue Gu Xinyan Zhai Kegong Tian 《Virus genes》2015,51(3):375-384
13.
猪繁殖与呼吸综合征病毒感染仔猪淋巴细胞亚群的动态 总被引:11,自引:0,他引:11
目的:研究SPF仔猪感染猪繁殖与呼吸综合征病毒后对猪瘟苗的免疫应答受到抑制的机理。方法:利用流式细胞术检测了SPF仔猪感染PRRS病毒BJ-4后外周血淋巴细胞亚群的动态。结果:外周血CD3^ 、CD4^ 、CD8^ 和SLA-DR^ 表达细胞在感染早期比例下降;感染猪扁桃体的CD3^ 和CD4^ CD8^ 细胞亚群比例下降;肠系膜淋巴结的CD3^ 细胞亚群在感染后细胞在感染早期比例下降;感染猪扁桃体的CD3^ 和CD4^ CD8^ 细胞亚群比例下降;肠系膜淋巴结的CD3^ 细胞在感染后下降,但是SLA-DR^ 细胞亚群有逐渐升高的趋势。结论:仔猪感染PRRS病毒后淋巴细胞各亚群的比例下降可能会抑制机体对其它病原体的免疫反应,扁桃体的细胞比例变化有利于其它呼吸道病原体的混合感染或继发感染。 相似文献
14.
Stadejek T Oleksiewicz MB Scherbakov AV Timina AM Krabbe JS Chabros K Potapchuk D 《Archives of virology》2008,153(8):1479-1488
The nucleocapsid protein of the European genotype of porcine reproductive and respiratory syndrome virus (type 1, PRRSV-1) exhibited extensive size polymorphism (124-130 amino acids), correlating with phylogenetic grouping of ORF7 as well as ORF5 nucleotide sequences, thereby validating ORF7 size as an independent PRRSV-1 subtype marker. Based on new sequence information from the Russian Federation, we propose division of European genotype PRRSV-1 into 3 subtypes: a pan-European subtype 1 and East European subtypes 2 and 3, with nucleocapsid protein sizes of 128, 125 and 124 amino acids, respectively. The genetic differences between European genotype PRRSV subtypes affected diagnostic RT-PCR primer binding sites. Using Escherichia coli-expressed ORF7 protein, we confirmed that even the relatively closely related PRRSV subtypes 2 and 3 were antigenically different. Finally, the isoelectric point (pI) correlated with the nucleocapsid protein size for European genotype PRRSV subtypes, suggesting subtype-specific compensatory structural changes associated with subtype-specific ORF7 sizes. Thus, the new ORF7-based subtype division of PRRSV-1 proposed here is biologically meaningful and practically relevant. 相似文献
15.
Sipos W Duvigneau C Pietschmann P Höller K Hartl R Wahl K Steinborn R Gemeiner M Willheim M Schmoll F 《Viral immunology》2003,16(3):335-346
Parameters of humoral and cellular immunity were investigated in pigs experimentally infected with a modified-live European porcine reproductive and respiratory syndrome virus (PRRSV, strain DV). PRRSV was detected by real-time RT-PCR and PRRSV-specific antibodies by a commercial ELISA test-kit, respectively. Interleukins IL-1alpha, IL-2, IL-4, IL-6, IL-8, IL-10, tumor necrosis factor (TNF-alpha) and interferon-gamma (IFN-gamma) as well as IL-2 receptor (IL-2R) were quantified at mRNA level using RT-PCR. Subpopulations of blood lymphocytes were assayed using flow cytometry. No significant changes neither in cytokine expression nor in shifts of CD4 and CD8 markers could be found, but similar curve diagrams concerning CD8 single positive T cells could be observed in all vaccinated animals with an initial decrease and an increase between post-infection days (PIDs) 7 and 14. In the vaccination group, TNF-alpha and IL-6 tended to be increased at PIDs 22 and 40, whereas no increase could be seen in IFN-gamma. When comparing the in vivo immune response to that being seen in in vitro experiments, similar shifts of CD4/CD8 lymphocyte subpopulations may be seen. Cytokine curve diagrams, however, do not reflect the in vitro findings to that extent. 相似文献
16.
Erika Silva-Campa Lorenzo Fraile Lilian Flores-Mendoza Jesús Hernández 《Virology》2010,396(2):264-8204
The aim of this study was to characterize the immune responses of DCs after infection with four different EU strains of PRRSV and whether they show any ability to immunomodulate T cells activation. Our results show that all EU strains can efficiently infect and replicate in DCs. Nevertheless, SLA-II levels remained unaltered in DC infected by all EU PRRSV strains, whereas SLA-I expression was only reduced when strain 2992 was used. IL-10 production was induced by three EU PRRSV strains, being strain 2992 the highest inducer. However, no induction of Treg cells, measured by CD25 and Foxp3 expression on lymphocytes co-cultured with infected DCs, was found. TGF-β induction was not detected in DC infected with any EU strain tested. In conclusion, DCs infected with EU PRRSV strains exhibited an unbalanced ability to stimulate T cell response and was strain dependent. However, Treg cells were not induced, at least in vitro. 相似文献
17.
Porcine reproductive and respiratory syndrome (PRRS) is a swine disease of major economic importance that causes reproductive
and respiratory problems in pigs. PRRSV strains are divided into European (Type 1) and North-American (Type 2) genotypes.
Within the European PRRSV genotype, three subtypes have been delineated. Full genome sequences for North American and European
subtype 1 strains have been described. Here, the first complete genomic characterization of a European subtype 3 strain (Lena)
is described. Amplification of Orf1a and Orf1b fragments was achieved using a set of degenerate oligonucleotides. Using RT-PCR
with Lena-specific primers, the full length sequence (15001 nt) was obtained. Alignment of Lena with European subtype 1 reference
strain Lelystad showed variation over the entire length (84% identity/89% similarity at amino acid level) with the most variation
in Orf1a (Nsp2/NSP2) with a deletion of 29 amino acids. Phylogenetic relationships using different Orfs supported Lena’s genetic
distinction from European subtype 1 strains. The availability of the European subtype 3 PRRSV full genome may be important
for the understanding of PRRSV evolution and the more pronounced pathogenic nature of Lena. 相似文献
18.
Han K Seo HW Shin JH Oh Y Kang I Park C Chae C 《Clinical and Vaccine Immunology : CVI》2011,18(10):1600-1607
The objective of the present study was to compare the effects of the modified live porcine reproductive and respiratory syndrome virus (PRRSV) vaccine (Ingelvac PRRS MLV; Boehringer Ingelheim Animal Health, St. Joseph, MO) on European and North American PRRSV shedding in the semen of experimentally infected boars. The boars were randomly divided into six groups. Vaccinated boars shed the North American PRRSV at the rate of 10(0.1) to 10(1.0) viral genome copies per ml and 3.63 to 10(1.1) 50% tissue culture infective doses (TCID(50))/ml, respectively, in semen, whereas nonvaccinated boars shed the North American PRRSV at the rate of 10(0.2) to 10(4.7) viral genome copies per ml and 1.14 to 10(3.07) TCID(50)/ml, respectively, in semen. Vaccinated boars shed the European PRRSV at the rate of 10(0.1) to 10(4.57) viral genome copies per ml and 1.66 to 10(3.10) TCID(50)/ml, respectively, in semen, whereas nonvaccinated boars shed the European PRRSV at the rate of 10(0.3) to 10(5.14) viral genome copies per ml and 1.69 to 10(3.17) TCID(50)/ml, respectively, in semen. The number of genomic copies of the European PRRSV in semen samples was not significantly different between vaccinated and nonvaccinated challenged European PRRSV boars. The present study demonstrated that boar vaccination using commercial modified live PRRSV vaccine was able to decrease subsequent shedding of North American PRRSV in semen after challenge but was unable to decrease shedding of European PRRSV in semen after challenge. 相似文献
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López-Fuertes L Campos E Doménech N Ezquerra A Castro JM Domínguez J Alonso F 《Virus research》2000,69(1):41-46
The effect of porcine reproductive and respiratory syndrome (PRRS) virus infection on the synthesis and secretion of TNF-alpha and other pro-inflammatory cytokines by porcine alveolar macrophages (PAM) was investigated as well as the effect that TNF-alpha has on the replication of this virus. A clear reduction of phorbol myristate acetate (PMA)-induced expression of TNF-alpha mRNA was observed in cells incubated with PRRS virus. Moreover, the presence of PRRS virus also induced a decrease in IL-1 alpha and MIP-1 beta mRNAs expression with respect to PMA-stimulated uninfected cells. According to these results, exposure to the PRRS virus led to a reduction of the TNF-alpha protein in supernatants of PMA-stimulated PAM. On the other hand, addition of recombinant porcine TNF-alpha to cultures clearly reduced virus replication; however the addition of TNF-alpha to cultures containing IFN-alpha did not result in a further reduction of the produced by IFN-alpha alone. This indicates the lack of synergy in the effect of these cytokines on viral replication. 相似文献
20.
Full-length sequence of a Canadian porcine reproductive and respiratory syndrome virus (PRRSV) isolate 总被引:10,自引:0,他引:10
Summary. Presently, one of the most economically important pathogens affecting swine is the porcine reproductive and respiratory syndrome
virus (PRRSV). This virus is prevalent in herds throughout the world and continues to pose a significant threat as newer and
more virulent disease phenotypes emerge. In this report we describe the full-length nucleotide sequence of a Canadian PRRSV
isolate, designated PA8. A consecutive sequence of 15,411 nucleotides was obtained from a set of overlapping cDNA clones.
In order to determine the extent of genetic variation among isolates recovered from swine in Canada and the US, as well as
to understand the molecular mechanisms governing the evolution of PRRSV, the full-length sequence of PA8 was compared with
that of two US isolates, VR2332 and 16244B. The genomic sequence of PA8 shared 98.2% and 99.2% identity with 16244B and VR2332,
respectively. The untranslated regions (UTR) at the 5′ and 3′ ends of the genome were very well conserved. Notable exceptions
include an eight nucleotide difference at the 5′ end of the 5′ UTR of VR2332 relative to PA8 and 16244B and a two nucleotide
difference in the 3′ UTR of PA8 relative to VR2332 and 16244B. In contrast to PA8 and VR2332, 16244B possessed two nucleotide
differences within the RNA pseudoknot structure of the ribosomal frameshift region between open reading frame (ORF)1a and
ORF1b. Amino acid differences were distributed throughout the genome, however they appeared to be most extensive in Nsp1β
and ORF5 of the nonstructural and structural coding regions, respectively, suggesting that the evolutionary pressure to conserve
these viral genes is somewhat lower.
Received January 10, 2000/Accepted May 22, 2000 相似文献