References of "Gillet, Laurent"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailMurine gammaherpesvirus-68 glycoprotein B presents a difficult neutralization target to monoclonal antibodies derived from infected mice.
Gillet, Laurent ULg; Gill, Michael B; Colaco, Susanna et al

in Journal of General Virology (The) (2006), 87(Pt 12), 3515-27

Persistent viruses disseminate from immune hosts. They must therefore resist neutralization by antibody. Murine gammaherpesvirus-68 (MHV-68) represents an accessible model with which to address how ... [more ▼]

Persistent viruses disseminate from immune hosts. They must therefore resist neutralization by antibody. Murine gammaherpesvirus-68 (MHV-68) represents an accessible model with which to address how resistance to neutralization is achieved and how overcoming it might improve infection control. The MHV-68 glycoprotein B (gB), like that of other herpesviruses, is a virion protein that is essential for infectivity. As such, it presents a potential neutralization target. In order to test whether virus-induced antibodies reduce virion infectivity by binding to gB, monoclonal antibodies (mAbs) were derived from MHV-68-infected mice. gB-specific mAbs were common, but only an IgM specific for the gB N terminus reduced virion infectivity significantly. It inhibited MHV-68 entry into BHK-21 cells at a post-binding step that was linked closely to membrane fusion. Reducing the mAb to IgM monomers compromised neutralization severely, suggesting that a pentameric structure was crucial to its function. Antibody treatment never blocked BHK-21 cell infection completely and blocked the infection of NMuMG epithelial cells hardly at all. Virions saturated with antibody also remained infectious to mice. Thus, the MHV-68 gB presents at best a very difficult target for antibody-mediated neutralization. [less ▲]

Detailed reference viewed: 21 (1 ULg)
Peer Reviewed
See detailDemonstration by flow cytometry that CD5+CD8+ cells carry alcelaphine herpesvirus 1 in inoculated rabbits developing malignant catarrhal fever
Dewals, Benjamin G ULg; Gillet, Laurent ULg; Vanderplasschen, Alain ULg

Poster (2005, November 18)

Alcelaphine herpesvirus 1 (AlHV 1), carried by wildebeest (Connochaetes taurinus) asymptomatically, causes malignant catarrhal fever (MCF) when cross species transmitted to a variety of susceptible ... [more ▼]

Alcelaphine herpesvirus 1 (AlHV 1), carried by wildebeest (Connochaetes taurinus) asymptomatically, causes malignant catarrhal fever (MCF) when cross species transmitted to a variety of susceptible species of the Artiodactyla order. MCF is a fascinating disease described as a combination of lymphoproliferative and degenerative lesions. The study of MCF pathogenesis has been impeded by an inability to produce recombinant virus, due mainly to the fact that AlHV 1 becomes attenuated during passage in culture. Here, we have overcome these difficulties by (i) cloning the entire AlHV 1 genome as a stable, infectious and pathogenic bacterial artificial chromosome (BAC), and (ii) by using prokaryotic recombination technology for the production of an AlHV 1 recombinant. Firstly, the AlHV 1 genome was BAC cloned using one insertion site in a region containing no open reading frame. This insertion allowed the production of an AlHV 1 BAC clone stably maintained in bacteria and able to regenerate virions when transfected into permissive cells. BAC derived AlHV 1 virions induced MCF in rabbits comparably to the AlHV 1 wild type (WT) strain. Secondly, a two step mutagenesis procedure in E. coli was used to generate a recombinant strain expressing enhanced-green fluorescent protein (EGFP) as a reporter gene. After reconstitution of recombinant virions into permissive cells and excision of the BAC cassette, flow cytometry analyses were performed to validate the recombinant strain and to investigate the pathogenesis of MCF. The results of these analyses can be summarized as follows: (i) the validity of the EGFP expression cassette as a reporter gene has been demonstrated by in vitro infections; (ii) inoculation of rabbits revealed that the recombinant strain has retained the pathogenicity of its parental strain and that the cell types carrying AlHV-1 in peripheral blood mononuclear cells, lymph nodes and the spleen are mainly CD5+ CD8+ cells. [less ▲]

Detailed reference viewed: 13 (3 ULg)
Full Text
Peer Reviewed
See detailClonage de l’herpèsvirus alcélaphin 1 sous forme d’un chromosome artificiel bactérien infectieux
Dewals, Benjamin G ULg; Boudry, Christel; Markine-Goriaynoff, Nicolas et al

Poster (2005, April)

L’herpèsvirus alcélaphin 1 (AlHV-1) est un Gammaherpesvirinae du genre Rhadinovirus ayant pour hôte naturel le gnou (Connochaetes taurinus). Apathogène pour son hôte naturel, ce virus induit par ailleurs ... [more ▼]

L’herpèsvirus alcélaphin 1 (AlHV-1) est un Gammaherpesvirinae du genre Rhadinovirus ayant pour hôte naturel le gnou (Connochaetes taurinus). Apathogène pour son hôte naturel, ce virus induit par ailleurs une pathologie mortelle lorsqu’il est transmis à un grand nombre d’espèces de ruminants sensibles. Cette pathologie, appelée forme africaine du coryza gangreneux (FACG) est associée à une lymphoprolifération et une destruction des tissus de l’hôte infecté. Pour étudier le rôle de l’AlHV-1 dans la pathogenèse de la FACG, il est nécessaire de pouvoir manipuler le génome viral afin de générer des virus recombinants et révertants pour certains gènes. A ce jour, aucune souche d’AlHV-1 recombinante n’a pu être produite. Cette carence résulte du fait que ce virus est strictement associé aux cellules et qu’il possède la caractéristique de s’atténuer spontanément lors de sa multiplication in vitro. De ce fait, la réalisation de virus mutants se révèle impossible par une approche classique de recombinaison homologue en cellules eucaryotes. Récemment, le développement des technologies de chromosome artificiel bactérien (BAC) a permis de cloner le génome entier de plusieurs gammaherpèsvirus de manière stable en bactérie ainsi que la production rapide de nombreuses souches recombinantes. Dans la présente étude, nous avons cloné le génome entier de la souche C500 de l’AlHV-1 sous forme d’un BAC appelé ci-après BAC-AlHV-1. Les résultats obtenus peuvent se résumer comme suit : (i) le BAC-AlHV-1 permet une propagation stable du génome de l’AlHV-1 en bactérie ; (ii) la transfection du BAC-AlHV-1 en cellules eucaryotes permet de régénérer des particules virales infectieuses ; (iii) la cassette BAC insérée initialement dans le génome de l’AlHV-1 étant flanquée de séquences loxP, la multiplication des virions générés à partir du BAC-AlHV-1 en cellules EBL-Cre (embryonic bovine lung ; exprimant la Cre recombinase) permet l’excision de la cassette BAC ; (iv) enfin, la capacité des virions générés à partir du BAC à induire la FACG en modèle lapin a été démontrée. En conclusion, le clone BAC-AlHV-1 généré dans cette étude va enfin permettre l’étude des rôles des différents gènes de l’AlHV-1 dans la genèse de la FACG. [less ▲]

Detailed reference viewed: 50 (19 ULg)
Full Text
Peer Reviewed
See detailGynogenesis induction and sex determination in the Eurasian perch, Perca fluviatilis
Rougeot, Carole ULg; Ngingo, J. V.; Gillet, Laurent ULg et al

in Aquaculture (2005), 243(1-4), 411-415

In the present study, we used meiotic gynogenesis, widely used in studies on sex determination, to confirm female homogamety in Eurasian perch, Perca fluviatilis. Sperm irradiated with UV for 400 s was ... [more ▼]

In the present study, we used meiotic gynogenesis, widely used in studies on sex determination, to confirm female homogamety in Eurasian perch, Perca fluviatilis. Sperm irradiated with UV for 400 s was used to artificially fertilized eggs. The diploid of the resulting embryos was restored by a heat shock (30 degreesC) applied to the eggs 5 min postfertilization, for 25 min. Fertilization (ranging between 45% and 75%) and survival rates at hatching (ranging between 3.4% and 46.6%) were not significantly different (P>0.05) between the diploid control and gynogenetics. The diploid controls and two batches of gynogenetics contained 100% diploid larvae, whereas two other batches of gynogenetics contained 6.7% and 10.0% triploid larvae. The sex ratios of the diploid controls were not significantly different from 1:1, whereas all gynogenetic families were 100% female. These results confirm female homogamety in Eurasian perch, demonstrated by the use of hormonally mascilinized breeders in a previous study. (C) 2004 Elsevier B.V. All rights reserved. [less ▲]

Detailed reference viewed: 190 (9 ULg)
Full Text
Peer Reviewed
See detailShort communication: Pasteurization of milk abolishes bovine herpesvirus 4 infectivity.
Bona, C.; Dewals, Benjamin G ULg; Wiggers, L. et al

in Journal of Dairy Science (2005), 88(9), 3079-83

Bovine herpesvirus 4 (BoHV-4) is a gammaherpesvirus highly prevalent in the cattle population that has been isolated from the milk and the serum of healthy infected cows. Several studies reported the ... [more ▼]

Bovine herpesvirus 4 (BoHV-4) is a gammaherpesvirus highly prevalent in the cattle population that has been isolated from the milk and the serum of healthy infected cows. Several studies reported the sensitivity and the permissiveness of some human cells to BoHV-4 infection. Moreover, our recent study demonstrated that some human cells sensitive but not permissive to BoHV-4 support a persistent infection protecting them from tumor necrosis factor-alpha-induced apoptosis. Together, these observations suggested that BoHV-4 could represent a danger for public health. To evaluate the risk of human infection by BoHV-4 through milk or serum derivatives, we investigated the resistance of BoHV-4 to the mildest thermal treatments usually applied to these products. The results demonstrated that milk pasteurization and thermal decomplementation of serum abolish BoHV-4 infectivity by inactivation of its property to enter permissive cells. Consequently, our results demonstrate that these treatments drastically reduce the risk of human infection by BoHV-4 through treated milk or serum derivatives. [less ▲]

Detailed reference viewed: 26 (4 ULg)
Full Text
Peer Reviewed
See detailBovine herpesvirus 4 induces apoptosis of human carcinoma cell lines in vitro and in vivo
Gillet, Laurent ULg; Dewals, Benjamin G ULg; Farnir, Frédéric ULg et al

in Cancer Research (2005), 65(20), 9463-9472

The idea of using oncolytic viruses for the treatment of cancers was proposed a century ago. During the last two decades, viruses able to replicate specifically in cancer cells and to induce their lysis ... [more ▼]

The idea of using oncolytic viruses for the treatment of cancers was proposed a century ago. During the last two decades, viruses able to replicate specifically in cancer cells and to induce their lysis were identified and were genetically modified to improve their viro-oncolytic properties. More recently, a new approach consisting of inducing selective apoptosis in cancer cells through viral infection has been proposed; this approach has been called viro-oncoapoptosis. In the present study, we report the property of bovine herpesvirus-4 (BoHV-4) to induce, in vitro and in vivo, apoptosis of some human carcinomas. This conclusion relies on the following observations: (a) In vitro, BoHV-4 infection induced apoptosis of A549 and OVCAR carcinoma cell lines in a time- and dose-dependent manner. (b) Apoptosis was induced by the expression of an immediate-early or an early BoHV-4 gene, but did not require viral replication. (c) Cell treatment with caspase inhibitors showed that apoptosis induced by BoHV-4 relied mainly on caspase-10 activation. (d) Infection of cocultures of A549 or OVCAR cells mixed with human 293 cells (in which BoHV-4 does not induce apoptosis) showed that BoHV-4 specifically eradicated A549 or OVCAR cancer cells from the cocultures. (e) Finally, in vivo experiments done with nude mice showed that BoHV-4 intratumoral injections reduced drastically the growth of preestablished A549 xenografts. Taken together, these results suggest that BoHV-4 may have potential as a viro-oncoapoptotic agent for the treatment of some human carcinomas. Moreover, further identification of BoHV-4 proapoptotic gene(s) and the cellular pathways targeted by this or these gene(s) could lead to the design of new cancer therapeutic strategies. [less ▲]

Detailed reference viewed: 22 (5 ULg)
Full Text
Peer Reviewed
See detailAntibodies against bovine herpesvirus 4 are highly prevalent in wild African buffaloes throughout eastern and southern Africa
Dewals, Benjamin G ULg; Gillet, Laurent ULg; Gerdes, Truuske et al

in Veterinary Microbiology (2005), 110(3-4), 209-220

Bovine herpesvirus 4 (BoHV-4) has been isolated from cattle throughout the world. Interestingly, a survey of wild African buffaloes mainly from the Maasai Mara Game Reserve in Kenya revealed that 94% of ... [more ▼]

Bovine herpesvirus 4 (BoHV-4) has been isolated from cattle throughout the world. Interestingly, a survey of wild African buffaloes mainly from the Maasai Mara Game Reserve in Kenya revealed that 94% of the animals tested had anti-BoHV-4 antibodies [Rossiter, P.B., Gumm, I.D., Stagg, D.A., Conrad, PA., Mukolwe, S., Davies, F.G., White, H., 1989. Isolation of bovine herpesvirus-3 from African buffaloes (Syncerus caffer). Res. Vet. Sci. 46, 337-343]. These authors also proposed that the serological antigenic relationship existing between BoHV-4 and alcelaphine herpesvirus I (A1HV-1) could confer to BoHV-4 infected buffaloes a protective immune response against lethal A1HV-1 infection. In the present study, we addressed two questions related to Rossiter et al. paper. Firstly, to investigate the role of the African buffalo as a natural host species of BoHV-4, the seroprevalence of anti-BoHV-4 antibodies was analysed in wild African buffaloes throughout eastern and southern Africa. A total of 400 sera was analysed using two complementary immunofluorescent assays. These analyses revealed that independently of their geographical origin, wild African buffaloes exhibit a seroprevalence of anti-BoHV-4 antibodies higher than 68%. This result is by far above the seroprevalence generally observed in cattle. Our data are discussed in the light of our recent phylogenetic study demonstrating that the BoHV-4 Bo17 gene has been acquired from a recent ancestor of the African buffalo. Secondly, we investigated the humoral antigenic relationship existing between BoHV-4 and A1HV-1. Our results demonstrate that among the antigens expressed in A1HV-1 infected cells, epitope(s) recognised by anti-BoHV-4 antibodies are exclusively nuclear, suggesting that the putative property of BoHV-4 to confer an immune protection against A1HV-1 relies on a cellular rather than on a humoral immune response. (c) 2005 Elsevier B.V. All rights reserved. [less ▲]

Detailed reference viewed: 35 (8 ULg)
Full Text
Peer Reviewed
See detailDevelopment of bovine herpesvirus 4 as an expression vector using bacterial artificial chromosome cloning.
Gillet, Laurent ULg; Daix, V.; Donofrio, G. et al

in Journal of General Virology (The) (2005), 86(Pt 4), 907-17

Several features make bovine herpesvirus 4 (BoHV-4) attractive as a backbone for use as a viral expression vector and/or as a model to study gammaherpesvirus biology. However, these developments have been ... [more ▼]

Several features make bovine herpesvirus 4 (BoHV-4) attractive as a backbone for use as a viral expression vector and/or as a model to study gammaherpesvirus biology. However, these developments have been impeded by the difficulty in manipulating its large genome using classical homologous recombination in eukaryotic cells. In the present study, the feasibility of exploiting bacterial artificial chromosome (BAC) cloning and prokaryotic recombination technology for production of BoHV-4 recombinants was explored. Firstly, the BoHV-4 genome was BAC cloned using two potential insertion sites. Both sites of insertion gave rise to BoHV-4 BAC clones stably maintained in bacteria and able to regenerate virions when transfected into permissive cells. Reconstituted virus replicated comparably to wild-type parental virus and the loxP-flanked BAC cassette was excised by growing them on permissive cells stably expressing Cre recombinase. Secondly, BoHV-4 recombinants expressing Ixodes ricinus anti-complement protein I or II (IRAC I/II) were produced using a two-step mutagenesis procedure in Escherichia coli. Both recombinants induced expression of high levels of functional IRAC molecules in the supernatant of infected cells. This study demonstrates that BAC cloning and prokaryotic recombination technology are powerful tools for the development of BoHV-4 as an expression vector and for further fundamental studies of this gammaherpesvirus. [less ▲]

Detailed reference viewed: 16 (3 ULg)
Full Text
Peer Reviewed
See detailPro-inflammatory properties for thiazolidinediones.
Desmet, Christophe ULg; Warzée, Barbara ULg; Gosset, Philippe et al

in Biochemical Pharmacology (2005), 69(2), 255-265

Thiazolidinediones (TZDs) are pharmacological ligands of the peroxisome proliferator-activated receptor (PPAR)-gamma that are extensively used in the treatment of type II diabetes. Recently, an anti ... [more ▼]

Thiazolidinediones (TZDs) are pharmacological ligands of the peroxisome proliferator-activated receptor (PPAR)-gamma that are extensively used in the treatment of type II diabetes. Recently, an anti-inflammatory potential for TZDs has been suggested, based on observations that these compounds may inhibit pro-inflammatory cytokine expression in vitro and may attenuate the inflammatory response in vivo. Here, we show that the TZDs rosiglitazone (RSG) and troglitazone (TRO) do not inhibit the inflammatory response to tumor necrosis factor (TNF)-alpha in various epithelial cell types. On the contrary, both RSG and TRO significantly potentiated TNF-alpha-induced production of granulocyte/macrophage-colony-stimulating factor, interleukin (IL)-6 and/or IL-8 in these cells. This increase in pro-inflammatory cytokine expression was functionally significant as supernatants from cells co-treated with TNF-alpha and TZDs displayed increased neutrophil pro-survival activity when compared with supernatants from cells treated with TNF-alpha alone. Additionally, it was shown that TZDs enhance cytokine expression at the transcriptional level, but that the pro-inflammatory effects of TZDs are independent on PPARgamma, nuclear factor kappaB or mitogen-activated protein kinase activation. Our study shows that TZDs may potentiate the inflammatory response in epithelial cells, a previously unappreciated effect of these compounds [less ▲]

Detailed reference viewed: 118 (24 ULg)
Full Text
Peer Reviewed
See detailGenetic immunisation of cattle against bovine herpesvirus 1: glycoprotein gD confers higher protection than glycoprotein gC or tegument protein VP8.
Toussaint, Jean-Francois; Coen, Laurent; Letellier, Carine et al

in Veterinary Research (2005), 36(4), 529-44

Bovine herpesvirus 1 (BoHV-1) has frequently been used as a model for testing parameters affecting DNA immunisation in large animals like cattle. However, the selection of target antigens has been poorly ... [more ▼]

Bovine herpesvirus 1 (BoHV-1) has frequently been used as a model for testing parameters affecting DNA immunisation in large animals like cattle. However, the selection of target antigens has been poorly studied, and most of the experiments have been conducted in mice. In the present study, we demonstrated in cattle that a DNA vaccine encoding BoHV-1 glycoprotein gD induces higher neutralising antibody titres than vaccines encoding BoHV-1 gC. Additionally, we show that a DNA vaccine encoding a secreted form of gD induces a higher immune response than a vaccine encoding full-length gD. However, the enhanced immunogenicity associated with the secretion of gD could not be extended to the glycoprotein gC. The current study also describes for the first time the development and the evaluation of a DNA vaccine encoding the major tegument protein VP8. This construct, which is the first BoHV-1 plasmid vaccine candidate that is not directed against a surface glycoprotein, induced a high BoHV-1 specific cellular immunity but no humoral immune response. The calves vaccinated with the constructs encoding full-length and truncated gD showed a non-significant tenfold reduction of virus excretion after challenge. Those calves also excreted virus for significantly (p < 0.05) shorter periods (1.5 days) than the non-vaccinated controls. The other constructs encoding gC and VP8 antigens induced no virological protection as compared to controls. Altogether the DNA vaccines induced weaker immunity and protection than conventional marker vaccines tested previously, confirming the difficulty to develop efficient DNA vaccines in large species. [less ▲]

Detailed reference viewed: 27 (7 ULg)
Full Text
Peer Reviewed
See detailCeramides play a critical role in spontaneous neutrophil apoptosis
Seumois, G.; Fillet, Marianne ULg; Gillet, Laurent ULg et al

in Pflügers Archiv : European Journal of Physiology (2004), 447

Detailed reference viewed: 16 (5 ULg)
Full Text
Peer Reviewed
See detailSTAT5 promotes granulocyte survival during inflammation
Fievez, Laurence ULg; Desmet, Christophe ULg; Pajak, B. et al

in Pflügers Archiv : European Journal of Physiology (2004), 447

Detailed reference viewed: 28 (4 ULg)
Full Text
Peer Reviewed
See detailGlycosyltransferases encoded by viruses.
Markine-Goriaynoff, Nicolas; Gillet, Laurent ULg; Van Etten, James L et al

in Journal of General Virology (The) (2004), 85(Pt 10), 2741-54

Studies of cellular biology in recent decades have highlighted the crucial roles of glycans in numerous important biological processes, raising the concept of glycomics that is now considered as important ... [more ▼]

Studies of cellular biology in recent decades have highlighted the crucial roles of glycans in numerous important biological processes, raising the concept of glycomics that is now considered as important as genomics, transcriptomics and proteomics. For millions of years, viruses have been co-evolving with their hosts. Consequently, during this co-evolution process, viruses have acquired mechanisms to mimic, hijack or sabotage host processes that favour their replication, including mechanisms to modify the glycome. The importance of the glycome in the regulation of host-virus interactions has recently led to a new concept called 'glycovirology'. One fascinating aspect of glycovirology is the study of how viruses affect the glycome. Viruses reach that goal either by regulating expression of host glycosyltransferases or by expressing their own glycosyltransferases. This review describes all virally encoded glycosyltransferases and discusses their established or putative functions. The description of these enzymes illustrates several intriguing aspects of virology and provides further support for the importance of glycomics in biological processes. [less ▲]

Detailed reference viewed: 15 (1 ULg)
Full Text
Peer Reviewed
See detailThe core 2 beta-1,6-N-acetylglucosaminyltransferase-M encoded by bovine herpesvirus 4 is not essential for virus replication despite contributing to post-translational modifications of structural proteins.
Markine-Goriaynoff, Nicolas; Gillet, Laurent ULg; Karlsen, Odd A et al

in Journal of General Virology (The) (2004), 85(Pt 2), 355-67

The Bo17 gene of bovine herpesvirus 4 (BoHV-4) is the only virus gene known to date that encodes a homologue of the cellular core 2 beta-1,6-N-acetylglucosaminyltransferase-mucine type (C2GnT-M). Recently ... [more ▼]

The Bo17 gene of bovine herpesvirus 4 (BoHV-4) is the only virus gene known to date that encodes a homologue of the cellular core 2 beta-1,6-N-acetylglucosaminyltransferase-mucine type (C2GnT-M). Recently, our phylogenetic study revealed that the Bo17 gene has been acquired from an ancestor of the African buffalo around 1.5 million years ago. Despite this recent origin, the Bo17 sequence has spread to fixation in the virus population possibly by natural selection. Supporting the latter hypothesis, it has been shown by our group for the V. test strain that Bo17 is expressed during BoHV-4 replication in vitro, and that Bo17 expression product (pBo17) has all three enzymic activities exhibited by cellular C2GnT-M, i.e. core 2, core 4 and I branching activities. In the present study, firstly it was investigated whether encoding a functional C2GnT-M is a general property of BoHV-4 strains. Analysis of nine representative strains of the BoHV-4 species revealed that all of them express the Bo17 gene and the associated core 2 branching activity during virus replication in vitro. Secondly, in order to investigate the roles of Bo17, its kinetic class of expression was analysed and a deleted recombinant strain was produced. These experiments revealed that Bo17 is expressed as an early gene which is not essential for virus replication in vitro. However, comparison of the structural proteins, produced by the wild-type, the revertant and the deleted viruses, by 2D gels demonstrated that pBo17 contributes to the post-translational modifications of structural proteins. Possible roles of Bo17 in vivo are discussed. [less ▲]

Detailed reference viewed: 23 (3 ULg)
Full Text
Peer Reviewed
See detailDelayed neutrophil apoptosis in bovine subclinical mastitis.
Boutet, Philippe ULg; Boulanger, D.; Gillet, Laurent ULg et al

in Journal of Dairy Science (2004), 87(12), 4104-4114

Bovine subclinical mastitis can be defined as a moderated inflammatory disease characterized by a persistent accumulation of neutrophils in milk. As GMCSF-mediated delay of neutrophil apoptosis ... [more ▼]

Bovine subclinical mastitis can be defined as a moderated inflammatory disease characterized by a persistent accumulation of neutrophils in milk. As GMCSF-mediated delay of neutrophil apoptosis contributes to the accumulation of inflammatory cells at the site of inflammation in many human diseases, we sought to determine whether subclinical mastitis in cows is also associated with a GMCSF-dependent increase in milk-neutrophil survival. We first addressed the hypothesis that GMCSF delays bovine neutrophil apoptosis by activation of the signal transducer and activator of transcription (STAT) family members STAT3 and STAT5, which are critical regulators of the expression of various Bcl-2 family proteins. Granulocyte-macrophage colony-stimulating factor significantly delayed apoptosis of blood neutrophils obtained from healthy cows. In these cells, GMCSF activated STAT5, but not STAT3, and induced an increase in the mRNA of the antiapoptotic Bcl-2 member, Bcl-xL. Granulocyte-macrophage colony-stimulating factor-dependent STAT5 activation and up-regulation of Bcl-xL mRNA were blocked by the Jak inhibitor, AG-490. This inhibition was associated with abrogation of the prosurvival effect of GMCSF, demonstrating a key role for STAT5 in delayed neutrophil apoptosis. We further found that GMCSF expression was increased in milk cells from cows affected with subclinical mastitis. Neutrophils from these cows demonstrated a significant delay of apoptosis as compared with neutrophils obtained from healthy cows and were unresponsive to GMCSF. Active STAT5 complexes were detected in these neutrophils. Finally, in the presence of AG-490, apoptosis was induced and a time-dependent down-regulation of Bcl-xL mRNA was observed in milk neutrophils from mastitis-affected cows. These results indicate that neutrophil survival is enhanced in milk of subclinical mastitis-affected cows and suggest a role for a GMCSF-activated STAT5 signaling pathway in this phenomenon. This pathway could thus represent a target for the control of persistent accumulation of neutrophils in the bovine mammary gland [less ▲]

Detailed reference viewed: 51 (13 ULg)
Full Text
Peer Reviewed
See detailInvestigation of the susceptibility of human cell lines to bovine herpesvirus 4 infection: Demonstration that human cells can support a nonpermissive persistent infection which protects them against tumor necrosis factor alpha-induced apoptosis
Gillet, Laurent ULg; Minner, F.; Detry, Bruno et al

in Journal of Virology (2004), 78(5), 2336-2347

Bovine herpesvirus 4 (BoHV-4) is a gammaherpesvirus that has a worldwide distribution in the population of cattle. Many factors make human contamination by BoHV-4 likely to occur. In this study, we ... [more ▼]

Bovine herpesvirus 4 (BoHV-4) is a gammaherpesvirus that has a worldwide distribution in the population of cattle. Many factors make human contamination by BoHV-4 likely to occur. In this study, we performed in vitro experiments to assess the risk and the consequences of human infection by BoHV-4. First, by using a recombinant BoHV-4 strain expressing enhanced green fluorescent protein under the control of the human cytomegalovirus immediate-early gene promoter, we tested 21 human cell lines for their sensitivity and their permissiveness to BoHV-4 infection. These experiments revealed that human cell lines from lymphoid and myeloid origins were resistant to infection, whereas epithelial cells, carcinoma cells, or adenocarcinoma cells isolated from various organs were sensitive but poorly permissive to BoHV-4 infection. Second, by using the HeLa cell line as a model of human cells sensitive but not permissive to BoHV-4 infection, we investigated the resistance of infected cells to apoptosis and the persistence of the infection through cellular divisions. The results obtained can be summarized as follows. (i) BoHV-4 nonpermissive infection of HeLa cells protects them against tumor necrosis factor alpha-induced apoptosis. (ii) BoHV-4 infection of HeLa cells persists in cell culture; however, the percentage of infected cells decreases with time due to erratic transmission of the viral genome through cell division. (iii) BoHV-4 infection has no effect on the rate of HeLa cell division. Altogether, these data suggest that BoHV-4 could infect humans. This study also stresses the importance of considering the insidious effects of nonpermissive infection when the biosafety of animal gammaherpesviruses for humans is being considered. [less ▲]

Detailed reference viewed: 70 (15 ULg)
Peer Reviewed
See detailSTAT5 promotes granulocyte survival during lung inflammation
Fievez, Laurence ULg; Desmet, Christophe ULg; Seumois, G. et al

in Proceedings: 22nd Symposium of the Veterinary and Comparative Respiratory Society (2004)

Detailed reference viewed: 29 (8 ULg)
Peer Reviewed
See detailAntiapoptotic effect of GM-CSF activated STAT5 signaling pathway in chronic mastitis-affected cows : possible involvement in persistent accumulation of neutrophils in milk
Boutet, Philippe ULg; Bureau, Fabrice ULg; Gillet, Laurent ULg et al

in Congress COST Action 844: “Apoptosis and programmed cell death : molecular mechanisms and applications in Biotechnology and Agriculture” (2004)

Detailed reference viewed: 23 (7 ULg)
Peer Reviewed
See detailCeramides play a critical role in spontaneous neutrophil apoptosis
Seumois, G.; Fillet, Marianne ULg; Gillet, Laurent ULg et al

Poster (2003)

Detailed reference viewed: 8 (5 ULg)