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Martin Beer - One of the best experts on this subject based on the ideXlab platform.
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classical swine fever Vaccines state of the art
Veterinary Microbiology, 2017Co-Authors: Sandra Blome, Ilona Reimann, Claudia Mos, Patricia Konig, Martin BeerAbstract:Due to its impact on animal health and pig industry, classical swine fever (CSF) is still one of the most important viral diseases of pigs. To control the disease, safe and highly efficacious live attenuated Vaccines exist for decades. These Vaccines have usually outstanding efficacy and safety but lack differentiability of infected from vaccinated animals (DIVA or Marker strategy). In contrast, the first generation of E2 subunit Marker Vaccines shows constraints in efficacy, application, and production. To overcome these limitations, new generations of Marker Vaccines are developed. A wide range of approaches have been tried including recombinant Vaccines, recombinant inactivated Vaccines or subunit Vaccines, vector Vaccines, and DNA/RNA Vaccines. During the last years, especially attenuated deletion Vaccines or chimeric constructs have shown potential. At present, especially two new constructs have been intensively tested, the adenovirus-delivered, Semliki Forest virus replicon-vectored Marker Vaccine candidate “rAdV-SFV-E2” and the pestivirus chimera “CP7_E2alf”. The later was recently licensed by the European Medicines Agency. Under field conditions, all Marker Vaccines have to be accompanied by a potent test system. Particularly this point shows still weaknesses and it is important to embed vaccination in a well-established vaccination strategy and a suitable diagnostic workflow. In summary, conventional Vaccines are a standard in terms of efficacy. However, only Vaccines with DIVA will allow improved eradication strategies e.g. also under emergency vaccination conditions in free regions. To answer this demand, new generations of Marker Vaccines have been developed and add now to the tool box of CSF control.
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molecular double check strategy for the identification and characterization of suid herpesvirus 1
Journal of Virological Methods, 2014Co-Authors: Kerstin Wernike, Thomas C. Mettenleiter, Barbara G Klupp, C. Freuling, Martin Beer, Thomas Muller, Bernd HoffmannAbstract:Large scale vaccination with glycoprotein E (gE)-deleted Marker Vaccines and the rapid and reliable differentiation of wild-type and Marker Vaccine strains are important aspects in eradication programs for Suid herpesvirus 1 [SuHV-1, syn. Aujeszky's disease virus (ADV) or pseudorabies virus (PrV)]. Therefore, two multiplex real-time PCR (qPCR) assays for the genetic differentiation of wild-type and gE-deleted Vaccine SuHV-1 strains have been developed. In the first multiplex qPCR SuHV-1 gB-gene specific detection was combined with a gE-gene specific assay and an internal control based on heterologous DNA. In the second system, a SuHV-1 UL19 (major capsid protein gene) assay, a different gE-gene specific assay and an internal control based on the beta-actin gene were combined. The gB-gene, UL19 as well as both gE-gene specific assays had an analytical sensitivity of less than 10 genome copies per reaction in the respective multiplex approaches. A series of reference strains including field isolates obtained from domestic and wild animals, and gE-deleted SuHV-1 were reliably detected, while genetically related non-SuHV-1 herpesviruses tested negative. Both newly developed triplex SuHV-1-specific qPCR assays are specific and sensitive methods for the rapid genetic differentiation of wild-type viruses and gE-deleted Vaccine strains in a single reaction.
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efficient generation of recombinant rna viruses using targeted recombination mediated mutagenesis of bacterial artificial chromosomes containing full length cdna
BMC Genomics, 2013Co-Authors: Thomas Bruun Rasmussen, Ilona Reimann, Peter Christian Risager, Ulrik Fahnoe, Martin Barfred Friis, Graham J Belsham, Dirk Hoper, Martin BeerAbstract:Infectious cDNA clones are a prerequisite for directed genetic manipulation of RNA viruses. Here, a strategy to facilitate manipulation and rescue of classical swine fever viruses (CSFVs) from full-length cDNAs present within bacterial artificial chromosomes (BACs) is described. This strategy allows manipulation of viral cDNA by targeted recombination-mediated mutagenesis within bacteria. A new CSFV-BAC (pBeloR26) derived from the Riems Vaccine strain has been constructed and subsequently modified in the E2 coding sequence, using the targeted recombination strategy to enable rescue of chimeric pestiviruses (vR26_E2gif and vR26_TAV) with potential as new Marker Vaccine candidates. Sequencing of the BACs revealed a high genetic stability during passages within bacteria. The complete genome sequences of rescued viruses, after extensive passages in mammalian cells showed that modifications in the E2 protein coding sequence were stably maintained. A single amino acid substitution (D3431G) in the RNA dependent RNA polymerase was observed in the rescued viruses vR26_E2gif and vR26, which was reversion to the parental Riems sequence. These results show that targeted recombination-mediated mutagenesis provides a powerful tool for expediting the construction of novel RNA genomes and should be applicable to the manipulation of other RNA viruses.
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characterization of a new chimeric Marker Vaccine candidate with a mutated antigenic e2 epitope
Veterinary Microbiology, 2010Co-Authors: Ilona Reimann, Klaus Depner, Katrin Utke, Immanuel Leifer, Elke Lange, Martin BeerAbstract:A new chimeric pestivirus "CP7_E1E2alf_TLA", based on the infectious cDNA of bovine viral diarrhea virus (BVDV) strain CP7, was constructed. The substitution of BVDV E1 and E2 with the respective proteins of classical swine fever (CSF) strain Alfort 187 allows an optimal heterodimerization of E1 and E2 in the chimeric virus, which is beneficial for efficient and authentic virus assembly and growth. In addition, for implementation of E2-based Marker diagnostics, the previously described antigenic CSFV-specific TAVSPTTLR epitope was exchanged with the corresponding E2-epitope of BVDV strain CP7. Recombinant virus CP7_E1E2alf_TLA displayed a growth defect, and was not reacting with monoclonal antibodies used in commercial E2 antibody blocking ELISAs. Therefore, efficacy as well as Marker properties of CP7_E1E2alf_TLA were investigated in an animal experiment with both a high dose and a low dose Vaccine preparation. All CP7_E1E2alf_TLA-vaccinated animals seroconverted until day 28 post-vaccination with neutralizing antibodies. Furthermore, at the day of challenge infection CP7_E1E2alf_TLA-immunized animals showed distinct lower ELISA values in a commercial CSFV E2 antibody test in comparison to the C-strain vaccinated controls. However, E2-ELISA reactivity as well as neutralizing titers were directly connected to the dosage used for vaccination, and only the low dose group had E2-ELISA values below threshold until challenge infection. Following challenge infection with highly virulent CSFV strain Koslov, all Vaccinees were protected, however, short-term fever episodes and very limited CSFV genome detection with very low copy numbers could be observed. In conclusion, manipulation of the TAVSPTTLR-epitope within the tested chimeric virus resulted in an slightly reduced efficacy, but the E2 Marker properties unexpectedly did not allow a clear differentiation of infected from vaccinated animals in some cases.
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differentiation of c strain riems or cp7_e2alf vaccinated animals from animals infected by classical swine fever virus field strains using real time rt pcr
Journal of Virological Methods, 2009Co-Authors: Immanuel Leifer, Sandra Blome, Mariefrederique Le Potier, Martin Beer, Klaus Robert Depner, Mireille Le Dimna, Bernd HoffmannAbstract:Classical swine fever (CSF) is one of the most important diseases of pigs. Although prophylactic vaccination is banned within the European Union, emergency vaccination, allowing differentiation of vaccinated from infected animals, is an option for disease control. Up to now, these strategies are based on antibody detection. In this context, conventional modified live Vaccines are not suitable. A promising perspective could be genetic differentiation of vaccinated from infected animals where field virus strains are differentiated from Vaccine viruses by sequence differences. This concept could also be used with Marker Vaccines. To this end, a set of real-time reverse transcription-polymerase chain reaction (RT-PCR) assays was developed and validated. Specific primers and probes were designed for detection of the C-strain "Riems" Vaccine virus or the chimeric Marker Vaccine candidate CP7_E2alf. A heterologous internal positive control was also included. The assays were then multiplexed to detect simultaneously either CSF field virus, C-strain "Riems", and the internal control or CSF field virus, CP7_E2alf, and the internal control. To validate both systems, samples from vaccination/challenge trials were tested. Only samples from vaccinated animals were found to be positive, while all samples from wild type virus-infected animals and a broad test panel of different pestiviruses were negative. Field application of the "C-strain Riems" specific assay was proven with wild boar samples from surveillance programs in Germany and France. In conclusion, ready-to-use RT-PCR sets are presented as reliable tools for genetic differentiation of vaccinated from infected animals for CSFV eradication strategies. (c) 2009 Elsevier B.V. All rights reserved
J.t. Van Oirschot - One of the best experts on this subject based on the ideXlab platform.
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virulence immunogenicity and reactivation of bovine herpesvirus 1 mutants with a deletion in the gc gg gi ge or in both the gi and ge gene
Vaccine, 1998Co-Authors: M.j. Kaashoek, Etienne Thiry, Frans A.m. Rijsewijk, Günther M. Keil, R C Ruuls, Paulpierre Pastoret, J.t. Van OirschotAbstract:Within the framework of developing a Marker Vaccine against bovine herpesvirus 1 (BHV1), several mutants with deletions in non-essential glycoprotein genes were constructed. Glycoprotein gC, gG, gI and gE single deletion mutants, a gIgE double deletion mutant and a gE frame-shift mutant were made. The virulence and immunogenicity of these mutants were evaluated in specific-pathogen-free calves. Except for the gC deletion mutant, all mutants were significantly less virulent than the parental wildtype (wt) BHV1 strain Lam. The virulence of the gI− and the gI−gE− mutants was almost completely reduced. Upon challenge infection, the calves of the control group became severely ill, whereas all other calves remained healthy. The reduction of the virus shedding after challenge infection was related to the virulence of the strain of primary inoculation. Virus shedding was almost completely reduced in calves first inoculated with Lam-wt or with gC− and the least reduced in calves inoculated with gI− or gI−gE−. Six weeks after challenge, all calves were treated with dexamethasone to study whether mutant or challenge virus or both could be reactivated. The gC− and the gG− mutants were reactivated, whereas none of the other mutants were reisolated. Reactivation of challenge virus was reduced in all calves inoculated with mutant viruses. The gC deletion mutant was too virulent and the gI and the gIgE deletion mutants were the least immunogenic, but based on residual virulence and immunogenicity, both the gG and the gE deletion mutants are candidates for incorporation in live BHV1 Vaccines. However, it also depends on the kinetics of the anti-gG and anti-gE antibody response after wild-type virus infection, whether these deletion mutants are really suitable to be incorporated in a Marker Vaccine.
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an attenuated bovine herpesvirus 1 Marker Vaccine induces a better protection than two inactivated Marker Vaccines
Veterinary Microbiology, 1996Co-Authors: J.c. Bosch, M.j. Kaashoek, A H Kroese, J.t. Van OirschotAbstract:A comparative study on the efficacy of 3 bovine herpesvirus 1 (BHV1) Marker Vaccines was carried out. An attenuated gE-negative Vaccine, an inactivated gE-negative Vaccine and an experimental gD-subunit Vaccine were tested twice in a vaccination-challenge experiment in cattle. The attenuated Vaccine induced the best clinical protection as evidenced by the total absence of clinical signs and fever in cattle. In addition, the attenuated Vaccine reduced the shedding of challenge virus significantly more than the inactivated Vaccines. Of the inactivated Vaccines, the gE-negative Vaccine induced a better clinical protection than the gD-subunit Vaccine.
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an inactivated Vaccine based on a glycoprotein e negative strain of bovine herpesvirus 1 induces protective immunity and allows serological differentiation
Vaccine, 1995Co-Authors: M.j. Kaashoek, Frans A.m. Rijsewijk, A. Moerman, J. Madic, K Weerdmeester, M A Marisveldhuis, J.t. Van OirschotAbstract:The bovine herpesvirus 1 (BHV1) strain Za is a conventionally attenuated strain with a 2.7 kb deletion that encompasses the complete coding region for glycoprotein E (gE). This gE-negative strain was used as whole-virus antigen in an inactivated virus Vaccine. Three different antigen concentrations of this Vaccine were evaluated for safety and efficacy in a vaccination-challenge experiment in calves. No adverse effects were observed in any of the calves vaccinated with the gE-negative Vaccines. Calves given the Vaccine with the highest antigen concentration were adequately protected against challenge; clinical symptoms were virtually absent and challenge virus shedding was significantly reduced as compared with unvaccinated calves. We developed a sensitive blocking enzyme-linked immunosorbent assay (ELISA) to detect antibodies against gE. After vaccination, calves did not produce antibodies against gE, but these antibodies were detectable within 2 weeks after challenge both in vaccinated and in unvaccinated calves. These results demonstrate the efficacy of a gE-negative inactivated BHV1 Vaccine and the detectability of antibodies against gE after infection. The combined use of the Marker Vaccine and the gE-blocking ELISA makes it possible to differentiate between vaccinated animals and infected animals. This possibility may be very useful in BHV1 control programmes.
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A glycoprotein E deletion mutant of bovine herpesvirus 1 is avirulent in calves.
Journal of General Virology, 1994Co-Authors: F.a.c. Van Engelenburg, Frans A.m. Rijsewijk, M.j. Kaashoek, L. Van Den Burg, A. Moerman, A. L. J. Gielkens, J.t. Van OirschotAbstract:A Marker Vaccine elicits an antibody response in the host that can be distinguished from the antibody response induced by a wild-type strain. To obtain a bovine herpesvirus 1 (BHV-1) Marker Vaccine, we constructed a glycoprotein E (gE) deletion mutant. This was obtained by removing the complete gE coding region from the BHV-1 genome. To attenuate the gE deletion mutant further, we also introduced a small deletion in the thymidine kinase (TK) gene. We selected three mutants: the gE deletion mutant, a TK deletion mutant and a gE/TK double deletion mutant, and examined their virulence and immunogenicity in calves. After intranasal inoculation, the TK deletion mutant showed some residual virulence, whereas the gE and gE/TK deletion mutants were avirulent. The calves inoculated with the deletion mutants were protected against disease after challenge exposure and shed significantly less virus than control calves. Deleting the gE gene, therefore, has little effect on the immunogenicity of BHV-1, but is sufficient to reduce the virulence of BHV-1 in calves. These findings led us to conclude that the gE deletion mutant is a good candidate for a modified live BHV-1 Marker Vaccine.
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A conventionally attenuated glycoprotein E-negative strain of bovine herpesvirus type 1 is an efficacious and safe Vaccine
Vaccine, 1994Co-Authors: M.j. Kaashoek, Frans A.m. Rijsewijk, A. Moerman, A. L. J. Gielkens, J. Madic, J. Quak, J.t. Van OirschotAbstract:We examined the Vaccine properties of a conventionally attenuated bovine herpesvirus type 1 (BHV-1) mutant strain A. This strain has a deletion that encompasses the glycoprotein E gene and may therefore be used as a Marker Vaccine. We compared strain A with a commercial live BHV-1 Vaccine B. Calves were intranasally vaccinated with strain A or with Vaccine B. Strain A was virtually avirulent for young calves. After challenge, vaccinated calves were protected against disease and virus shedding was considerably reduced. After dexamethasone treatment, strain A was not recovered, whereas Vaccine B and challenge virus were. We conclude that strain A is suitable for inclusion in a Vaccine and has the potential advantage of being used as a Marker Vaccine.
M.j. Kaashoek - One of the best experts on this subject based on the ideXlab platform.
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virulence immunogenicity and reactivation of bovine herpesvirus 1 mutants with a deletion in the gc gg gi ge or in both the gi and ge gene
Vaccine, 1998Co-Authors: M.j. Kaashoek, Etienne Thiry, Frans A.m. Rijsewijk, Günther M. Keil, R C Ruuls, Paulpierre Pastoret, J.t. Van OirschotAbstract:Within the framework of developing a Marker Vaccine against bovine herpesvirus 1 (BHV1), several mutants with deletions in non-essential glycoprotein genes were constructed. Glycoprotein gC, gG, gI and gE single deletion mutants, a gIgE double deletion mutant and a gE frame-shift mutant were made. The virulence and immunogenicity of these mutants were evaluated in specific-pathogen-free calves. Except for the gC deletion mutant, all mutants were significantly less virulent than the parental wildtype (wt) BHV1 strain Lam. The virulence of the gI− and the gI−gE− mutants was almost completely reduced. Upon challenge infection, the calves of the control group became severely ill, whereas all other calves remained healthy. The reduction of the virus shedding after challenge infection was related to the virulence of the strain of primary inoculation. Virus shedding was almost completely reduced in calves first inoculated with Lam-wt or with gC− and the least reduced in calves inoculated with gI− or gI−gE−. Six weeks after challenge, all calves were treated with dexamethasone to study whether mutant or challenge virus or both could be reactivated. The gC− and the gG− mutants were reactivated, whereas none of the other mutants were reisolated. Reactivation of challenge virus was reduced in all calves inoculated with mutant viruses. The gC deletion mutant was too virulent and the gI and the gIgE deletion mutants were the least immunogenic, but based on residual virulence and immunogenicity, both the gG and the gE deletion mutants are candidates for incorporation in live BHV1 Vaccines. However, it also depends on the kinetics of the anti-gG and anti-gE antibody response after wild-type virus infection, whether these deletion mutants are really suitable to be incorporated in a Marker Vaccine.
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an inactivated ge negative Marker Vaccine and an experimental gd subunit Vaccine reduce the incidence of bovine herpesvirus 1 infections in the field
Vaccine, 1998Co-Authors: J.c. Bosch, M.j. Kaashoek, M A Marisveldhuis, M C M De Jong, P Franken, K Frankena, J J Hage, J P T M Noordhuizen, W H M Van Der Poel, J VerhoeffAbstract:Abstract An inactivated glycoprotein E-negative Vaccine and an experimental glycoprotein D-subunit Vaccine against bovine herpesvirus 1 (V1) were examined for their effectiveness in a randomized, double-bline, placebo-controlled field trial comprising 130 dairy farms. The use of these Marker Vaccines enabled us to monitor the incidence of infections in vaccinated populations. The aims of this trial were to evaluate whether these Vaccines: (1) reduce the proportion of outbreaks in dairy herds; and (2) reduced virus transmission within dairy herds and to what extent. Vaccination with either of the two Vaccines significantly reduced the proportion of herds wherein an outbreak occurred as well as the virus transmission within herds, as compared to placebo-treated herds. The estimated number of secondary cases caused by one infectious animal, expressed as the reproduction ratio R , was for both Vaccines significantly >1. This indicates that when BHV1 is introduced into vaccinated herds, major outbreaks may still occur.
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an attenuated bovine herpesvirus 1 Marker Vaccine induces a better protection than two inactivated Marker Vaccines
Veterinary Microbiology, 1996Co-Authors: J.c. Bosch, M.j. Kaashoek, A H Kroese, J.t. Van OirschotAbstract:A comparative study on the efficacy of 3 bovine herpesvirus 1 (BHV1) Marker Vaccines was carried out. An attenuated gE-negative Vaccine, an inactivated gE-negative Vaccine and an experimental gD-subunit Vaccine were tested twice in a vaccination-challenge experiment in cattle. The attenuated Vaccine induced the best clinical protection as evidenced by the total absence of clinical signs and fever in cattle. In addition, the attenuated Vaccine reduced the shedding of challenge virus significantly more than the inactivated Vaccines. Of the inactivated Vaccines, the gE-negative Vaccine induced a better clinical protection than the gD-subunit Vaccine.
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an inactivated Vaccine based on a glycoprotein e negative strain of bovine herpesvirus 1 induces protective immunity and allows serological differentiation
Vaccine, 1995Co-Authors: M.j. Kaashoek, Frans A.m. Rijsewijk, A. Moerman, J. Madic, K Weerdmeester, M A Marisveldhuis, J.t. Van OirschotAbstract:The bovine herpesvirus 1 (BHV1) strain Za is a conventionally attenuated strain with a 2.7 kb deletion that encompasses the complete coding region for glycoprotein E (gE). This gE-negative strain was used as whole-virus antigen in an inactivated virus Vaccine. Three different antigen concentrations of this Vaccine were evaluated for safety and efficacy in a vaccination-challenge experiment in calves. No adverse effects were observed in any of the calves vaccinated with the gE-negative Vaccines. Calves given the Vaccine with the highest antigen concentration were adequately protected against challenge; clinical symptoms were virtually absent and challenge virus shedding was significantly reduced as compared with unvaccinated calves. We developed a sensitive blocking enzyme-linked immunosorbent assay (ELISA) to detect antibodies against gE. After vaccination, calves did not produce antibodies against gE, but these antibodies were detectable within 2 weeks after challenge both in vaccinated and in unvaccinated calves. These results demonstrate the efficacy of a gE-negative inactivated BHV1 Vaccine and the detectability of antibodies against gE after infection. The combined use of the Marker Vaccine and the gE-blocking ELISA makes it possible to differentiate between vaccinated animals and infected animals. This possibility may be very useful in BHV1 control programmes.
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A glycoprotein E deletion mutant of bovine herpesvirus 1 is avirulent in calves.
Journal of General Virology, 1994Co-Authors: F.a.c. Van Engelenburg, Frans A.m. Rijsewijk, M.j. Kaashoek, L. Van Den Burg, A. Moerman, A. L. J. Gielkens, J.t. Van OirschotAbstract:A Marker Vaccine elicits an antibody response in the host that can be distinguished from the antibody response induced by a wild-type strain. To obtain a bovine herpesvirus 1 (BHV-1) Marker Vaccine, we constructed a glycoprotein E (gE) deletion mutant. This was obtained by removing the complete gE coding region from the BHV-1 genome. To attenuate the gE deletion mutant further, we also introduced a small deletion in the thymidine kinase (TK) gene. We selected three mutants: the gE deletion mutant, a TK deletion mutant and a gE/TK double deletion mutant, and examined their virulence and immunogenicity in calves. After intranasal inoculation, the TK deletion mutant showed some residual virulence, whereas the gE and gE/TK deletion mutants were avirulent. The calves inoculated with the deletion mutants were protected against disease after challenge exposure and shed significantly less virus than control calves. Deleting the gE gene, therefore, has little effect on the immunogenicity of BHV-1, but is sufficient to reduce the virulence of BHV-1 in calves. These findings led us to conclude that the gE deletion mutant is a good candidate for a modified live BHV-1 Marker Vaccine.
R. J. M. Moormann - One of the best experts on this subject based on the ideXlab platform.
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development of a classical swine fever subunit Marker Vaccine and companion diagnostic test
Veterinary Microbiology, 2000Co-Authors: R. J. M. Moormann, A Bouma, C Terpstra, J A Kramps, H De SmitAbstract:Abstract The development of a classical swine fever (CSF) subunit Marker Vaccine, based on viral envelope glycoprotein E2, and a companion diagnostic test, based on a second viral envelope glycoprotein E RNS , will be described. Important properties of the Vaccine, such as onset and duration of immunity, and prevention of horizontal and vertical transmission of virus were evaluated. A single dose of the Vaccine protected pigs against clinical signs of CSF, following intranasal challenge with 100LD 50 of virulent classical swine fever virus (CSFV) at 2 weeks after vaccination. However, challenge virus transmission to unvaccinated sentinels was not always completely inhibited at this time point. From 3 weeks up to 6 months after vaccination, pigs were protected against clinical signs of CSF, and no longer transmitted challenge virus to unvaccinated sentinels. In contrast, unvaccinated control pigs died within 2 weeks after challenge. We also evaluated transmission of challenge virus in a setup enabling determination of the reproduction ratio ( R value) of the virus. In such an experiment, transmission of challenge virus is determined in a fully vaccinated population at different time points after vaccination. Pigs challenged at 1 week after immunization died of CSF, whereas the vaccinated sentinels became infected, seroconverted for E RNS antibodies, but survived. At 2 weeks after vaccination, the challenged pigs seroconverted for E RNS antibodies, but none of the vaccinated sentinels did. Thus, at 1 week after vaccination, R >1, and at 2 weeks, R =0, implying no control or control of an outbreak, respectively. Vertical transmission of CSFV to the immune-incompetent fetus may lead to the birth of highly viraemic, persistently infected piglets which are one of the major sources of virus spread. Protection against transplacental transmission of CSFV in vaccinated sows was, therefore, tested in once and twice vaccinated sows. Only one out of nine once-vaccinated sows transmitted challenge virus to the fetus, whereas none of the nine twice-vaccinated sows did. Finally, our data show that the E RNS test detects CSFV-specific antibodies in vaccinated or unvaccinated pigs as early as 14 days after infection with a virulent CSF strain. This indicates that the E2 Vaccine and companion test fully comply with the Marker Vaccine concept. This concept implies the possibility of detecting infected animals within a vaccinated population.
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efficacy and stability of a subunit Vaccine based on glycoprotein e2 of classical swine fever virus
Veterinary Microbiology, 1999Co-Authors: A Bouma, A J De Smit, E P De Kluijver, C Terpstra, R. J. M. MoormannAbstract:The purpose of this study was to determine the efficacy and stability of an E2 subunit Vaccine against classical swine fever virus (CSFV). The Vaccine, which contains E2 produced in insect cells by a baculovirus expression vector is a potential Marker Vaccine, as it allows discrimination between infected and vaccinated pigs. Several vaccination-challenge experiments were performed to determine the dose that protects 95% of the vaccinated pigs (PD95), and to determine the stability and efficacy of the Vaccine several months after production. A single vaccination with a Vaccine dose of 32 microg E2 - the estimated PD95 - in a water-oil-water adjuvant prevented clinical signs and mortality due to a CSFV challenge-inoculation three weeks after vaccination. Moreover, virus transmission to susceptible sentinel pigs was prevented in nearly all groups of pigs vaccinated with this dose. The Vaccine was stable for at least 18 months, and retained its full potency. These findings indicate that the E2 Marker Vaccine merits further evaluation for suitability for use in a control program during an outbreak of CSF.
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An experimental Marker Vaccine and accompanying serological diagnostic test both based on envelope glycoprotein E2 of classical swine fever virus (CSFV).
Vaccine, 1999Co-Authors: P.a. Van Rijn, H. G. P. Van Gennip, R. J. M. MoormannAbstract:Envelope glycoprotein E2 is the most immunogenic protein of classical swine fever virus (CSFV). In a proposed model of the antigenic structure of E2, the N-terminal half of E2 forms two independent structural antigenic units, A and BC. E2 without transmembrane region (E2-TMR) is expressed and secreted into the medium of insect cells by use of the baculovirus expression system. The immune response induced by E2 protects pigs against CSFV. Recently, we showed that the protective immune response to a homologous CSFV challenge can be induced by a single unit, A or BC, of E2. An indirect blocking ELISA, or complex trapping blocking assay (CTB) based on both units is routinely used worldwide for serological diagnosis of CSFV infections. Here we show that E2-TMR is secreted into the medium as a homodimer. This E2 homodimer was used to develop a CTB detecting antibodies directed against one immunogenic unit of E2. Thus, the protective immune response induced by E2 containing one unit was not detected with a modified CTB based on the other unit, whereas immune responses induced by a variety of low virulent CSFV strains were detected with such a modified CTB. These results indicate that a deletion E2 protein in combination with a modified CTB are feasible as CSF Marker Vaccine and accompanying differentiating diagnostic test.
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infectious rna transcribed from an engineered full length cdna template of the genome of a pestivirus
Journal of Virology, 1996Co-Authors: R. J. M. Moormann, H. G. P. Van Gennip, G K W Miedema, M M Hulst, P.a. Van RijnAbstract:Infectious RNA was transcribed for the first time from a full-length cDNA template of the plus-strand RNA genome of a pestivirus. The genome of the C strain, which is a Vaccine strain of classical swine fever virus, was sequenced and used to synthesize the template. The cDNA sequence of the C strain was found to be 12,311 nucleotides in length and contained one large open reading frame encoding a polyprotein of 3,898 amino acids. Although there were mostly only small differences between the sequence of the C strain and the published sequences of strains Alfort and Brescia, there was one notable insertion of 13 nucleotides, TTTTCTTTTTTTT, in the 3' noncoding region of the C strain. Furthermore, we showed that the sequences at the 5' and 3' termini of the C strain are highly conserved among pestiviruses. We found that the infectivity of the in vitro transcripts of DNA copies pPRKflc-113 and pPRKflc-133 depended on the correctness of the nucleotide sequence. The in vitro transcripts of pPRKflc-133 were infectious, whereas those of pPRKflc-113 were not. In fact, only 5 amino acids among the complete amino acid sequence determined this difference in infectivity. However, virus FLc-133, which was generated from pPRKflc-133, cannot be differentiated from native C-strain virus. Therefore, we exchanged the region encoding the antigenic N-terminal half of envelope protein E2 in pPRKflc-133 with the equivalent region of strain Brescia. The resulting hybrid virus, FLc-h6, could be differentiated from the C strain and from FLc-133 with monoclonal antibodies directed against envelope proteins Erns and E2 of strain Brescia and the C strain. To be suitable for further Vaccine development, viruses generated from pPRKflc-133 should grow at least as well as native C-strain virus. In fact, we found that FLc-133, hybrid virus FLc-h6, and the C strain grew equally well. We concluded that pPRKflc-133 is an excellent tool for developing a classical swine fever Marker Vaccine and may prove valuable for studying the replication, virulence, cell and host tropism, and pathogenesis of classical swine fever virus.
M Mcgee - One of the best experts on this subject based on the ideXlab platform.
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effect of suckler cow vaccination against glycoprotein e ge negative bovine herpesvirus type 1 bohv 1 on passive immunity and physiological response to subsequent bovine respiratory disease vaccination of their progeny
Research in Veterinary Science, 2018Co-Authors: Bernadette Earley, Katie Tiernan, Catherine Duffy, Amanda Dunn, Sinead M Waters, Steven Morrison, M McgeeAbstract:Abstract The study objectives were: 1) to characterise the development of immunocompetence in beef suckler calves from birth to three months of age, and 2) to trace glycoprotein E (gE)-negative bovine herpesvirus type 1 (BoHV-1) antibodies from dam to calf and subsequent vaccination against pneumonia. Thirty multiparous beef suckler, spring-calving cows, consisting of two genotypes were involved; Limousin × Friesian (LF) and Charolais × Limousin (CL). Cows were immunised against the inactivated antigen strain of BoHV-1 (gE- (IBR Marker Vaccine) at day − 84 and received a booster at day − 56 relative to the expected calving date (d 0). Calves were immunised at 14 and 42 days of age against PI-3 virus, BRSV and Mannheimia (Pasteurella) haemolytica serotype A1 using a commercial Vaccine administered subcutaneously. Additionally, calves were immunised against BoHV-1 at 42 days of age, using 1 dose of a live commercial Vaccine administered intranasally. Blood samples were collected from all calves (n = 30) via jugular venipuncture at birth, prior to colostrum feeding (0 h), at 12 h (h), 24 h, 72 h and 168 h after the initial feeding of colostrum, and at d 7, 14, 28, 42, 56 and 84 post birth. The mean ratio of gE negative antibodies circulating in the blood of LF and CL dams pre-partum scored negative to gE ab (S/N ≥ 0.70). Antibody levels of BoHV-1 (wild type (wt)) peaked at 12 h post-birth in calves and declined thereafter, as the maternal antibodies decayed. There was no difference in BoHV-1 and BRSV antibody levels in calves post vaccination.