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See detailIn vitro-generated interspecific recombinants between bovine herpesviruses 1 and 5 show attenuated replication characteristics and establish latency in the natural host
Del Medico Zajac, M. P.; Romera, S. A.; Ladelfa, M. F. et al

in BMC Veterinary Research (2011), 7

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See detailCharacterization of interspecific recombinants generated from closely related bovine herpesviruses 1 and 5 through multiple PCR sequencing assays
Del Médico Zajac, M. P.; Romera, S. A.; Ladelfa, M. F. et al

in Journal of Virological Methods (2009)

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See detailClinical Protection against Caprine Herpesvirus 1 Genital Infection by Intranasal Administration of a Live Attenuated Glycoprotein E Negative Bovine Herpesvirus 1 Vaccine
Thiry, Julien ULg; Tempesta, M.; Camero, M. et al

in BMC Veterinary Research (2007), 3

BACKGROUND: Caprine herpesvirus 1 (CpHV-1) is responsible of systemic diseases in kids and genital diseases leading to abortions in goats. CpHV-1 is widespread and especially in Mediterranean countries as ... [more ▼]

BACKGROUND: Caprine herpesvirus 1 (CpHV-1) is responsible of systemic diseases in kids and genital diseases leading to abortions in goats. CpHV-1 is widespread and especially in Mediterranean countries as Greece, Italy and Spain. CpHV-1 is antigenically and genetically closely related to bovine herpesvirus 1 (BoHV-1). Taking into account the biological properties shared by these two viruses, we decided in the current study to assess the protection of a live attenuated glycoprotein E (gE) negative BoHV-1 vaccine against a genital CpHV-1 infection in goats. RESULTS: The vaccine was inoculated intranasally twice three weeks apart followed by a subsequent CpHV-1 intravaginal challenge which is the natural route of infection in three goats. To analyse the safety and the efficacy of this marker vaccine, two groups of three goats served as controls: one immunised with a virulent CpHV-1 and one uninoculated until the challenge. Goats were clinically monitored and all sampling procedures were carried out in a blind manner. The vaccine did not induce any undesirable local or systemic reaction and goats did not excrete gE-negative BoHV-1. After challenge, a significant reduction in disease severity was observed in immunised goats. Moreover, goats immunised with either gE-negative BoHV-1 or CpHV-1 exhibited a significant reduction in the length and the peak of viral excretion. Antibodies neutralising both BoHV-1 and CpHV-1 were raised in immunised goats. CONCLUSION: Intranasal application of a live attenuated gE-negative BoHV-1 vaccine is able to afford a clinical protection and a reduction of virus excretion in goats challenged by a CpHV-1 genital infection. [less ▲]

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See detailIntraspecific bovine herpesvirus 1 recombinants carrying glycoprotein E deletion as a vaccine marker are virulent in cattle
Muylkens, Benoît ULg; Meurens, F.; Schynts, F. et al

in Journal of General Virology (2006), 87(Pt 8), 2149-2154

Vaccines used in control programmes of Bovine herpesvirus 1 (BoHV-1) utilize highly attenuated BoHV-1 strains marked by a deletion of the glycoprotein E (gE) gene. Since BoHV-1 recombinants are obtained ... [more ▼]

Vaccines used in control programmes of Bovine herpesvirus 1 (BoHV-1) utilize highly attenuated BoHV-1 strains marked by a deletion of the glycoprotein E (gE) gene. Since BoHV-1 recombinants are obtained at high frequency in experimentally coinfected cattle, the consequences of recombination on the virulence of gE-negative BoHV-1 were investigated. Thus, gE-negative BoHV-1 recombinants were generated in vitro from several virulent BoHV-1 and one mutant BoHV-1 deleted in the gC and gE genes. Four gE-negative recombinants were tested in the natural host. All the recombinants were more virulent than the gE-negative BoHV-1 vaccine and the gC- and gE-negative parental BoHV-1. The gE-negative recombinant isolated from a BoHV-1 field strain induced the highest severe clinical score. Latency and reactivation studies showed that three of the recombinants were reexcreted. Recombination can therefore restore virulence of gE-negative BoHV-1 by introducing the gE deletion into a different virulence background. [less ▲]

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See detailRecombination in the alphaherpesvirus bovine herpesvirus 1
Thiry, Etienne ULg; Muylkens, Benoît ULg; Meurens, F. et al

in Veterinary Microbiology (2006), 113(3-4), 171-177

Herpesviruses are DNA viruses characterized by a low rate of nucleotide substitution. Therefore. other mechanisms must be involved to their evolution, like recombination that can be seen as an essential ... [more ▼]

Herpesviruses are DNA viruses characterized by a low rate of nucleotide substitution. Therefore. other mechanisms must be involved to their evolution, like recombination that can be seen as an essential evolutionary driving force of these viruses. Recombination contributes to the long-term evolution of alphaherpes viruses. It acts also to continuously create new alphaherpesvirus strains. We have used bovine herpesvirus 1 to investigate recombination both within DNA concatemers in infected cells and in vitro and in vivo at the end of the lytic cycle. The following results have been obtained: (i) intramolecular recombination occurs at the level of concatemers and gives rise to genomic segment inversions: (ii) intraspecific recombination occurs frequently both in vitro and in vivo; (iii) interspecific recombination is possible and requires two highly genetically related viruses (iv) only simultaneous or closely separated infections lead to the production of recombinant viruses: (v) recombination between wild-type and glycoprotein defective vaccine virus can produce a glycoprotein defective virus keeping part of the virulence of parental wild-type virus. Recombination, by exchanging genomic segments, may modify the virulence of alphaherpesviruses. It must be carefully assessed for the biosafety of antiviral therapy, alphaherpesvirus-based vectors and live attenuated vaccines. (c) 2005 Elsevier B.V. All rights reserved. [less ▲]

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See detailBiological characterization of bovine herpesvirus 1 recombinants possessing the vaccine glycoprotein E negative phenotype
Muylkens, Benoît ULg; Meurens, F.; Schynts, F. et al

in Veterinary Microbiology (2006), 113(3-4), 283-291

Intramolecular recombination is a frequent event during the replication cycle of bovine herpesvirus 1 (BoHV-1). Recombinant viruses frequently arise and survive in cattle after concomitant nasal ... [more ▼]

Intramolecular recombination is a frequent event during the replication cycle of bovine herpesvirus 1 (BoHV-1). Recombinant viruses frequently arise and survive in cattle after concomitant nasal infections with two BoHV-1 mutants. The consequences of this process, related to herpesvirus evolution, have to be assessed in the context of large use of live marker vaccines based on glycoprotein E (gE) gene deletion. In natural conditions, double nasal infections by vaccine and wild-type strains are likely to occur. This situation might generate virulent recombinant viruses inducing a serological response indistinguishable from the vaccine one. This question was addressed by generating in vitro BoHV-1 recombinants deleted in the gE gene from seven wild-type BoHV-1 strains and one mutant strain deleted in the genes encoding gC and gE. In vitro growth properties were assessed by virus production, one step growth kinetics and plaque size assay. Heterogeneity in the biological properties was shown among the investigated recombinant viruses. The results demonstrated that some recombinants. in spite of their gE minus phenotype, have biological characteristics close to wild-type BoHV-1. (c) 2005 Elsevier B.V. All rights reserved. [less ▲]

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See detailRecombination in alphaherpesviruses
Thiry, Etienne ULg; Meurens, F.; Muylkens, Benoît ULg et al

in Reviews in Medical Virology (2005), 15(2, Mar-Apr), 89-103

Within the Herpesviridae family, Alphaherpesvirinae is an extensive subfamily which contains numerous mammalian and avian viruses. Given the low rate of herpesvirus nucleotide substitution, recombination ... [more ▼]

Within the Herpesviridae family, Alphaherpesvirinae is an extensive subfamily which contains numerous mammalian and avian viruses. Given the low rate of herpesvirus nucleotide substitution, recombination can be seen as an essential evolutionary driving force although it is likely underestimated. Recombination in alphaherpesviruses is intimately linked to DNA replication. Both viral and cellular proteins participate in this recombination-dependent replication. The presence of inverted repeats in the alphaherpesvirus genomes allows segment inversion as a consequence of specific recombination between repeated sequences during DNA replication. High molecular weight intermediates of replication, called concatemers, are the site of early recombination events. The analysis of concatemers, from cells coinfected by two distinguishable alphaherpesviruses provides an efficient tool to study recombination without the bias introduced by invisible or non-viable recombinants, and by dominance of a virus over recombinants. Intraspecific recombination frequently occurs between strains of the same alphaherpesvirus species. Interspecific recombination depends on enough sequence similarity to enable recombination between distinct alphaherpesvirus species. The most important prerequisite for successful recombination is coinfection of the individual host by different virus strains or species. Consequently the following factors affecting the distribution of different viruses to shared target cells need to be considered: dose of inoculated virus, time interval between inoculation of the first and the second virus, distance between the marker mutations, genetic homology, virulence and latency. Recombination, by exchanging genomic segments, may modify the virulence of alphaherpesviruses. It must be carefully assessed for the biosafety of antiviral therapy, alphaherpesvirus-based vectors and live attenuated vaccines. Copyright (C) 2004 John Wiley Sons, Ltd. [less ▲]

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See detailInterspecific recombination between two ruminant alphaherpesviruses, bovine herpesviruses 1 and 5
Meurens, F.; Keil, G. M.; Muylkens, Benoît ULg et al

in Journal of Virology (2004), 78(18), 9828-9836

Homologous recombination between different species of alphaherpesviruses has been described between herpes simplex viruses 1 and 2 but has not yet been observed between other alphaherpesviruses. In the ... [more ▼]

Homologous recombination between different species of alphaherpesviruses has been described between herpes simplex viruses 1 and 2 but has not yet been observed between other alphaherpesviruses. In the present study we chose to assess to what extent in vitro recombination can occur between members of a well-defined group of closely related viruses such as ruminant alphaherpesviruses. At 24 h after infection of epithelial bovine kidney cells with a double-deleted mutant of bovine herpesvirus 1 (BoHV-1) (containing green fluorescent protein and red fluorescent protein genes) and different ruminant alphaherpesviruses, four types of progeny viruses were detected and distinguished according to their phenotype. Frequent recombination events between identical or different strains of BoHV-1 were observed (up to 30%), whereas only two BoHV-1/BoHV-5 recombinants were identified, and no recombinants between BoHV-1 and less closely related caprine and cervine herpesviruses were detected. Restriction analysis of the genomes of the two BoHV-1/BoHV-5 recombinants showed different genetic backgrounds. One possessed a restriction pattern close to BoHV-1, whereas the other one was close to BoHV-5. This exhaustive analysis of each combination of coinfection in a unique situation of five closely related alphaherpesviruses revealed the importance of a high degree of genetic relatedness and similar parental virus growth kinetics for successful interspecific recombination. [less ▲]

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See detailSuperinfection prevents recombination of the alphaherpesvirus bovine herpesvirus 1
Meurens, F.; Schynts, F.; Keil, G. M. et al

in Journal of Virology (2004), 78(8), 3872-3879

Homologous recombination between strains of the same alphaherpesvirus species occurs frequently both in vitro and in vivo. This process has been described between strains of herpes simplex virus type 1 ... [more ▼]

Homologous recombination between strains of the same alphaherpesvirus species occurs frequently both in vitro and in vivo. This process has been described between strains of herpes simplex virus type 1, herpes simplex virus type 2, pseudorabies virus, feline herpesvirus 1, varicella-zoster virus, and bovine herpesvirus 1 (BoHV-1). In vivo, the rise of recombinant viruses can be modulated by different factors, such as the dose of the inoculated viruses, the distance between inoculation sites, the time interval between inoculation of the first and the second virus, and the genes in which the mutations are located. The effect of the time interval between infections with two distinguishable BoHV-1 on recombination was studied in three ways: (i) recombination at the level of progeny viruses, (ii) interference induced by the first virus infection on beta-gallactosidase gene expression of a superinfecting virus, and (iii) recombination at the level of concatemeric DNA. A time interval of 2 to 8 h between two successive infections allows the establishment of a barrier, which reduces or prevents any successful superinfection needed to generate recombinant viruses. The dramatic effect of the time interval on the rise of recombinant viruses is particularly important for the risk assessment of recombination between glycoprotein E-negative marker vaccine and field strains that could threaten BoHV-1 control and eradication programs. [less ▲]

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See detailRise and survival of bovine herpesvirus 1 recombinants after primary infection and reactivation from latency
Schynts, F.; Meurens, F.; Detry, Bruno et al

in Journal of Virology (2003), 77(23), 12535-12542

Recombination is thought to be an important source of genetic variation in herpesviruses. Several studies, performed in vitro or in vivo, detected recombinant viruses after the coinoculation of two ... [more ▼]

Recombination is thought to be an important source of genetic variation in herpesviruses. Several studies, performed in vitro or in vivo, detected recombinant viruses after the coinoculation of two distinguishable strains of the same herpesvirus species. However, none of these studies investigated the evolution of the relative proportions of parental versus recombinant progeny populations after coinoculation of the natural host, both during the excretion and the reexcretion period. In the present study, we address this by studying the infection of cattle with bovine herpesvirus 1 (BoHV-1). The recombination of two BoHV-1 mutants lacking either glycoprotein C (gC(-)/gE(+)) or E (gC(+)/gE(-)) was investigated after inoculation of cattle by the natural route of infection. The results demonstrated that (i) recombination is a frequent event in vivo since recombinants (gC(+)/gE(+) and gC(-)/gE(-)) were detected in all coinoculated calves, (ii) relative proportions of progeny populations evolved during the excretion period toward a situation where two populations (gC(+)/gE(+) and gC(-)/gE(+)) predominated without fully outcompeting the presence of the two other detected populations (gC(+)/gE(-) and gC(-)/gE(-)), and (iii) after reactivation from latency, no gC(+)/gE(-) and gC(-)/gE(-) progeny viruses were detected, although gC(+)/gE(-) mutants, when inoculated alone, were detected after reactivation treatment. In view of these data, the importance of gE in the biology of BoHV-1 infection and the role of recombination in herpesvirus evolution are discussed. [less ▲]

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See detailBiosafety of Herpesvirus Vectors
Gogev, S.; Schynts, F.; Meurens, F. et al

in Current Gene Therapy (2003), 3(6), 597-611

Herpesviruses are large DNA viruses, which possess a number of advantages as gene delivery vectors. These relate to an ability to package large DNA insertions and establish lifelong latent infections in ... [more ▼]

Herpesviruses are large DNA viruses, which possess a number of advantages as gene delivery vectors. These relate to an ability to package large DNA insertions and establish lifelong latent infections in which the viral genome exists as a stable episome in the nucleus. For gene therapy to become a potential future treatment option, biosafe therapeutically efficient gene transfer is a central, but more and more stringent requirement. This review highlights the progress in development of herpesvirus based vectors, describes their properties as wall as discusses the biosafety concerns that are associated with their use in gene therapy. Thought was also given to biosafety issues pertaining to design and production of herpesvirus vector systems in therapeutic gene delivery. [less ▲]

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See detailInsémination artificielle et transfert embryonnaire pour limiter la dissémination des maladies contagieuses chez les animaux de rente.
Gonzalez, F; Cabrera, F; Rodriguez, N et al

Conference (2003, November)

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See detailThe structures of bovine herpesvirus 1 virion and concatemeric DNA: implications for cleavage and packaging of herpesvirus genomes
Schynts, F.; McVoy, M. A.; Meurens, F. et al

in Virology (2003), 314(1), 326-335

Herpesvirus genomes are often characterized by the presence of direct and inverted repeats that delineate their grouping into six structural classes. Class D genomes consist of a long (L) segment and a ... [more ▼]

Herpesvirus genomes are often characterized by the presence of direct and inverted repeats that delineate their grouping into six structural classes. Class D genomes consist of a long (L) segment and a short (S) segment. The latter is flanked by large inverted repeats. DNA replication produces concatemers of head-to-tail linked genomes that are cleaved into unit genomes during the process of packaging DNA into capsids. Packaged class D genomes are an equimolar mixture of two isomers in which S is in either of two orientations, presumably a consequence of homologous recombination between the inverted repeats. The L segment remains predominantly fixed in a prototype (P) orientation; however, low levels of genomes having inverted L (I-L) segments have been reported for some class D herpesviruses. Inefficient formation of class D I-L genomes has been attributed to infrequent L segment inversion, but recent detection of frequent inverted L segments in equine herpesvirus 1 concatemers [Virology 229 (1997) 415-420] suggests that the defect may be at the level of cleavage and packaging rather than inversion. In this study, the structures of virion and concatemeric DNA of another class D herpesvirus, bovine herpesvirus 1, were determined. Virion DNA contained low levels of I-L genomes, whereas concatemeric DNA contained significant amounts of L segments in both P and I-L orientations. However, concatemeric termini exhibited a preponderance of L termini derived from P isomers which was comparable to the preponderance of P genomes found in virion DNA. Thus, the defect in formation of I-L genomes appears to lie at the level of concatemer cleavage. These results have important implications for the mechanisms by which herpesvirus DNA cleavage and packaging occur. (C) 2003 Elsevier Inc. All rights reserved. [less ▲]

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See detailArtificial insemination and embryo transfer as efficient tools to better control infectious diseases transmission
Gonzalez, F; Cabrera, F; Rodriguez, N et al

in Proceeding of artificial insemination and embryo transfer as efficient tools to better control infectious diseases transmission (2002, October 10)

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See detailInseminazione artificiale e transferimento embrionale come stumenti efficace per un miglior controllo sulla transmissione delle malattie infettive
Gonzalez, F; Cabrera, F; Rodriguez, N et al

Conference (2002, May 18)

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See detailL’herpèsvirus B du singe, un agent d’anthropozoonose méconnu
Meurens, F.; Gallego, P.; Bourgot, I. et al

in Annales de Médecine Vétérinaire (2002), 146(1, FEB-MAR), 1-8

B-virus or Cercopithecine herpesvirus 1 (CeHV-1) is a zoonotic alphaherpesvirus enzootic in Asian monkeys of the genus Macaca that is genetically and antigenically closely related to the human herpesvirus ... [more ▼]

B-virus or Cercopithecine herpesvirus 1 (CeHV-1) is a zoonotic alphaherpesvirus enzootic in Asian monkeys of the genus Macaca that is genetically and antigenically closely related to the human herpesvirus 1 and the human herpesvirus 2. CeHV-1 infection is highly prevalent (80% to 100%) in adult macaques and may lead to fulminant encephalomyelitis with severe aftereffects or even causing death in humans. Since its discovery in 1933, it has been positively linked with two dozen human deaths. B-virus disease in humans usually resulted from breach of primary skin or mucosal defenses and subsequent contamination of the site with virus. Timely antiviral intervention is a good mean of reducing CeHV-1 associated morbidity and preventing a fatal outcome. [less ▲]

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See detailLes xeno-oestrogènes et leur impact sur l’environnement
Meurens, F.; Delaunois, A.; Beckers, Jean-François ULg et al

in Annales de Médecine Vétérinaire (2000), 145

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