INTRODUCTION: Porcine reproductive and respiratory syndrome virus (PRRSV) emerged about 30 years ago and continues to cause major economic losses in the pork industry. The lack of effective modified live vaccines (MLV) allows the pandemic to continue. BACKGROUND AND OBJECTIVE: We have previously shown that wild strains of PRRSV affect the nascent T cell repertoire in the thymus, deplete T cell clones recognizing viral epitopes essential for neutralization, while triggering a chronic, robust, but ineffective antibody response. Therefore, we hypothesized that the current MLV are inappropriate because they cause similar damage and fail to prevent viral-induced dysregulation of adaptive immunity. METHODS: We tested three MLV strains to demonstrate that all have a comparable negative effect on thymocytes in vitro. Further in vivo studies compared the development of T cells in the thymus, peripheral lymphocytes, and antibody production in young piglets. These three MLV strains were used in a mixture to determine whether at least some of them behave similarly to the wild virus type 1 or type 2. RESULTS: Both the wild and MLV strains cause the same immune dysregulations. These include depletion of T-cell precursors, alteration of the TCR repertoire, necrobiosis at corticomedullary junctions, low body weight gain, decreased thymic cellularity, lack of virus-neutralizing antibodies, and production of non-neutralizing anti-PRRSV antibodies of different isotypes. DISCUSSION AND CONCLUSION: The results may explain why the use of current MLV in young animals may be ineffective and why their use may be potentially dangerous. Therefore, alternative vaccines, such as subunit or mRNA vaccines or improved MLV, are needed to control the PRRSV pandemic.
- MeSH
- atenuované vakcíny MeSH
- imunitní systém MeSH
- prasata MeSH
- protilátky virové MeSH
- reprodukční a respirační syndrom prasat * prevence a kontrola MeSH
- virus reprodukčního a respiračního syndromu prasat * MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The goals of our study were to compare the immune response to different killed and modified live vaccines against PRRS virus and to monitor the antibody production and the cell mediated immunity both at the systemic and local level. In the experiment, we immunized four groups of piglets with two commercial inactivated (A1-Progressis, A2-Suivac) and two modified live vaccines (B3-Amervac, B4-Porcilis). Twenty-one days after the final vaccination, all piglets, including the control non-immunized group (C5), were i.n., infected with the Lelystad strain of PRRS virus. The serum antibody response (IgM and IgG) was the strongest in group A1 followed by two MLV (B3 and B4) groups. Locally, we demonstrated the highest level of IgG antibodies in bronchoalveolar lavages (BALF), and saliva in group A1, whereas low IgA antibody responses in BALF and feces were detected in all groups. We have found virus neutralization antibody at DPV 21 (days post vaccination) and higher levels in all groups including the control at DPI 21 (days post infection). Positive antigen specific cell-mediated response in lymphocyte transformation test (LTT) was observed in groups B3 and B4 at DPV 7 and in group B4 at DPV 21 and in all intervals after infection. The IFN-γ producing lymphocytes after antigen stimulation were found in CD4-CD8+ and CD4+CD8+ subsets of all immunized groups 7 days after infection. After infection, there were obvious differences in virus excretion. The virus was detected in all groups of piglets in serum, saliva, and occasionally in feces at DPI 3. Significantly lower virus load was found in groups A1 and B3 at DPI 21. Negative samples appeared at DPI 21 in B3 group in saliva. It can be concluded that antibodies after immunization and infection, and the virus after infection can be detected in all the compartments monitored. Immunization with inactivated vaccine A1-Progressis induces high levels of antibodies produced both systemically and locally. Immunization with MLV-vaccines (Amervac and Porcilis) produces sufficient antibody levels and also cell-mediated immunity. After infection virus secretion gradually decreases in group B3, indicating tendency to induce sterile immunity.
- MeSH
- aktivace lymfocytů * MeSH
- inaktivované vakcíny imunologie MeSH
- prasata MeSH
- protilátky virové biosyntéza MeSH
- vakcinace * MeSH
- virová nálož MeSH
- virové vakcíny imunologie MeSH
- virus reprodukčního a respiračního syndromu prasat imunologie MeSH
- živé neatenuované vakcíny imunologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Porcine reproductive and respiratory syndrome virus (PRRSV) causes immune dysregulation during the Critical Window of Immunological Development. We hypothesize that thymocyte development is altered by infected thymic antigen presenting cells (TAPCs) in the fetal/neonatal thymus that interact with double-positive thymocytes causing an acute deficiency of T cells that produces "holes" in the T cell repertoire allowing for poor recognition of PRRSV and other neonatal pathogens. The deficiency may be the result of random elimination of PRRSV-specific T cells or the generation of T cells that accept PRRSV epitopes as self-antigens. Loss of helper T cells for virus neutralizing (VN) epitopes can result in the failure of selection for B cells in lymph node germinal centers capable of producing high affinity VN antibodies. Generation of cytotoxic and regulatory T cells may also be impaired. Similar to infections with LDV, LCMV, MCMV, HIV-1 and trypanosomes, the host responds to the deficiency of pathogen-specific T cells and perhaps regulatory T cells, by "last ditch" polyclonal B cell activation. In colostrum-deprived PRRSV-infected isolator piglets, this results in hypergammaglobulinemia, which we believe to be a "red herring" that detracts attention from the thymic atrophy story, but leads to our second independent hypothesis. Since hypergammaglobulinemia has not been reported in PRRSV-infected conventionally-reared piglets, we hypothesize that this is due to the down-regulatory effect of passive maternal IgG and cytokines in porcine colostrum, especially TGFβ which stimulates development of regulatory T cells (Tregs).
- MeSH
- hypergamaglobulinemie krev etiologie metabolismus MeSH
- imunoglobulinové izotypy krev imunologie MeSH
- interakce hostitele a patogenu imunologie MeSH
- náchylnost k nemoci MeSH
- pandemie MeSH
- prasata MeSH
- protilátky virové krev imunologie MeSH
- reprodukční a respirační syndrom prasat krev epidemiologie etiologie MeSH
- T-lymfocyty cytologie imunologie metabolismus MeSH
- thymocyty cytologie imunologie metabolismus MeSH
- thymus imunologie metabolismus MeSH
- virus reprodukčního a respiračního syndromu prasat fyziologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
In this study, we propose a possible way of obtaining reproductive and respiratory syndrome virus (PRRSV) free offspring from genetically valuable lines of Přeštice black-pied boars com- ming from PRRSV-positive pig breeding herds with the use of artificial insemination (AI). The ejaculates were collected from 4 different lines of boars. Samples of fresh semen were not detected with the virus and 12 sows were inseminated. Blood samples of sows and their offspring were repeatedly tested for the virus but the results were negative. We managed in this way to maintain the endangered population of this breed and obtain PRRSV-free offspring.
- MeSH
- chov MeSH
- prasata MeSH
- protilátky virové krev MeSH
- reprodukční a respirační syndrom prasat prevence a kontrola MeSH
- sperma virologie MeSH
- umělá inseminace veterinární MeSH
- vertikální přenos infekce prevence a kontrola veterinární MeSH
- virus reprodukčního a respiračního syndromu prasat MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Porcine reproductive and respiratory syndrome virus (PRRSV) predisposes pigs to secondary bacterial infection caused by Haemophilus parasuis. The aim of the present study was to analyse the immune response of monocyte-derived macrophages (MDMs), serving as a model of macrophages accumulating at the site of inflammation. The second part of the study was focused on the role of IFNα in the production of inflammatory cytokines in co-infected MDMs. Concurrent infection with PRRSV and H. parasuis decreased gene expression of pro-inflammatory cytokines (IL-1β, IL-8) in MDMs in comparison with MDMs infected with PRRSV or H. parasuis alone. Our data showed that MDMs express IFNα after PRRSV infection. Thereafter, we exposed cells to the experimental addition of IFNα and a subsequent infection with H. parasuis, and detected a decreased expression/production of pro-inflammatory cytokines. Thus, we assume that IFNα, produced after PRRSV infection, could affect the immune response of monocyte-derived macrophages. Down-regulation of pro-inflammatory cytokine expression in inflammatory macrophages may allow the development of secondary bacterial infections in pigs.
- MeSH
- bronchoalveolární laváž MeSH
- cytokiny genetika imunologie MeSH
- Haemophilus parasuis imunologie patogenita MeSH
- hemofilové infekce mikrobiologie veterinární MeSH
- interferon alfa imunologie farmakologie MeSH
- makrofágy účinky léků imunologie mikrobiologie virologie MeSH
- nemoci prasat mikrobiologie virologie MeSH
- prasata MeSH
- reprodukční a respirační syndrom prasat virologie MeSH
- viabilita buněk MeSH
- virus reprodukčního a respiračního syndromu prasat imunologie patogenita MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
More than 20 years after the first outbreaks, the phylogenetic picture of PRRSV is still incomplete and full of gaps, especially in regards of PRRSV 1. Due to the exceptional diversity observed at the eastern borders of Europe and the low number of available sequences from Central Eastern European countries, the authors collected and analyzed both recent as well as already submitted sequences comparing them to a large backbone set of available ORF5 sequences representing the full spectrum of PRRSV 1 Subtype 1 diversity to conduct a systematic phylogenetic analysis and reclassification elucidating the diversity of the virus in these countries. Moreover, further analyses of the EUROSTAT data regarding the live pig movement trends revealed their influence of virus diversity and evolution. The results indicate that besides the effect of local, isolated divergent evolution and the use of modified live vaccines, the most important factor influencing a given country's virus diversity is the transboundary movement of live, infected animals.
- MeSH
- DNA virů chemie MeSH
- fylogeneze MeSH
- fylogeografie MeSH
- genetická variace MeSH
- molekulární evoluce MeSH
- virus reprodukčního a respiračního syndromu prasat genetika MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- východní Evropa MeSH
Porcine reproductive and respiratory syndrome (PRRS) is one of the most significant and economically important infectious diseases affecting swine worldwide and can predispose pigs to secondary bacterial infections caused by, e.g. Haemophilus parasuis. The aim of the presented study was to compare susceptibility of two different types of macrophages which could be in contact with both pathogens during infection with PRRS virus (PRRSV) and in co-infection with H. parasuis. Alveolar macrophages (PAMs) as resident cells provide one of the first lines of defence against microbes invading lung tissue. On the other hand, monocyte derived macrophages (MDMs) represent inflammatory cells accumulating at the site of inflammation. While PAMs were relatively resistant to cytopathogenic effect caused by PRRSV, MDMs were much more sensitive to PRRSV infection. MDMs infected with PRRSV increased expression of pro-apoptotic Bad, Bax and p53 mRNA. Increased mortality of MDMs may be also related to a higher intensity of ROS production after infection with PRRSV. In addition, MDMs (but not PAMs) infected with H. parasuis alone formed multinucleated giant cells (MGC); these cells were not observed in MDMs infected with both pathogens. Higher sensitivity of MDMs to PRRSV infection, which is associated with limited MDMs survival and restriction of MGC formation, could contribute to the development of multifactorial respiratory disease of swine.
- MeSH
- Haemophilus parasuis * MeSH
- hemofilové infekce komplikace patologie veterinární virologie MeSH
- koinfekce metabolismus patologie veterinární MeSH
- makrofágy metabolismus patologie virologie MeSH
- obrovské buňky metabolismus patologie virologie MeSH
- prasata MeSH
- pyrimidiny MeSH
- reaktivní formy kyslíku metabolismus MeSH
- reprodukční a respirační syndrom prasat metabolismus patologie virologie MeSH
- sulfonamidy MeSH
- virus reprodukčního a respiračního syndromu prasat * MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Porcine reproductive and respiratory syndrome virus (PRRSV) can predispose pigs to secondary respiratory infection with bacteria such as Haemophilus parasuis. Animals infected with both pathogens develop more severe clinical disease. The immune response of porcine alveolar macrophages (PAMs) to simultaneous infection with PRRSV and H. parasuis was analysed in vitro, describing cytokine production, expression of cell surface molecules, and production of reactive oxygen species (ROS). Concurrent infection with PRRSV and H. parasuis increased gene expression of pro-inflammatory cytokines (TNF-α, IL-1β, IL-8) in PAMs in comparison with PAMs infected with PRRSV or H. parasuis alone. An additive effect of dual infection on IL-1β production was confirmed at the protein level. PAMs infected with PRRSV showed increased production of ROS compared to controls. Conversely, simultaneous infection of PAMs with PRRSV and H. parasuis decreased production of ROS, indicating the presence of an H. parasuis defence mechanism against respiratory burst. Concurrent infection of PAMs with PRRSV and H. parasuis was shown to elicit a pro-inflammatory immune response represented by significant IL-1β production. Severe multifactorial respiratory disease in natural conditions caused by both pathogens could be the consequence of pro-inflammatory mediated immunopathology.
- MeSH
- alveolární makrofágy imunologie mikrobiologie virologie MeSH
- biologické markery analýza MeSH
- cytokiny genetika imunologie MeSH
- Haemophilus parasuis imunologie MeSH
- hemofilové infekce komplikace imunologie veterinární virologie MeSH
- koinfekce veterinární MeSH
- kultivované buňky MeSH
- messenger RNA metabolismus MeSH
- nemoci prasat imunologie mikrobiologie virologie MeSH
- prasata MeSH
- regulace exprese virových genů MeSH
- regulace genové exprese u bakterií MeSH
- reprodukční a respirační syndrom prasat imunologie virologie MeSH
- virus reprodukčního a respiračního syndromu prasat imunologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
All twenty-nine PRRSV ORF7 nucleotide sequences obtained from clinical samples originating from the three Central European countries Austria (n = 7), Czech Republic (n = 12), and Slovakia (n = 10) belonged to type 1, subtype I (EU-1). Twenty-seven sequences encoded the typical length of the nucleocapsid protein composed of 128 amino acids. Two genetically identical ORF7s of PRRSV originating from a single farm in Slovakia showed a new length polymorphism of the nucleocapsid protein comprising 132 amino acids.
- MeSH
- fylogeneze MeSH
- genotyp MeSH
- lymfatické uzliny virologie MeSH
- molekulární sekvence - údaje MeSH
- nukleokapsida - proteiny genetika MeSH
- otevřené čtecí rámce MeSH
- plíce virologie MeSH
- polymorfismus genetický * MeSH
- prasata virologie MeSH
- reprodukční a respirační syndrom prasat virologie MeSH
- RNA virová krev MeSH
- sekvence aminokyselin MeSH
- sekvence nukleotidů MeSH
- sekvenční seřazení MeSH
- virus reprodukčního a respiračního syndromu prasat klasifikace genetika patogenita MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika MeSH
- Rakousko MeSH
- Slovenská republika MeSH
The aim of this work was to express recombinant nonstructural Nsp7 protein of European genotype of porcine reproductive and respiratory syndrome virus and to evaluate its diagnostic sensitivity and specificity in serological diagnostics of the disease. The gene coding for Nsp7 protein was expressed in Escherichia coli cells and purified by IMAC. Serological reactivity of purified protein was assessed on a panel of swine sera in indirect ELISA test. Serum samples originated from PRRS positive farms, herds free of PRRS infection and PRRS free herds vaccinated with an inactivated vaccine. Nsp7 antigen proved to be suitable for serological detection of PRRS specific antibodies, showing diagnostic sensitivity of 82.2% and specificity of 97.6% when compared with IDEXX ELISA test. The nonstructural protein proved to be suitable for use as an antigen for the differentiation of post-infection and post-vaccination antibodies in pigs vaccinated with the inactivated vaccine. But the low overall antibody response to N protein after this type of vaccination makes this concept rather theoretical.
- MeSH
- antigeny virové MeSH
- ELISA MeSH
- Escherichia coli MeSH
- genotyp MeSH
- protilátky virové MeSH
- regulace exprese virových genů fyziologie MeSH
- sérologické testy MeSH
- specificita protilátek MeSH
- virové proteiny genetika metabolismus MeSH
- virus reprodukčního a respiračního syndromu prasat genetika MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
