References of "Desmecht, Daniel"
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See detailContribution of MX dynamin, oligoadenylate synthetase, and protein kinase R to anti-paramyxovirus activity of type-1 interferons in vitro
Leroy, M.; Baise, Etienne ULg; Pire, G. et al

in American Journal of Veterinary Research (2007), 68

OBJECTIVE: To determine the contribution of MX dynamin, oligoadenylate synthetase (OAS), and double-stranded RNA-dependent protein kinase R (PKR) to the antiviral effects of type 1 interferons (IFNs ... [more ▼]

OBJECTIVE: To determine the contribution of MX dynamin, oligoadenylate synthetase (OAS), and double-stranded RNA-dependent protein kinase R (PKR) to the antiviral effects of type 1 interferons (IFNs) against bovine parainfluenza-3 virus (PI-3V) infection of Vero cells. SAMPLE POPULATION: Vero cell cultures. PROCEDURES: PI-3V yield was first compared between control and transfected type 1 IFNs-incompetent Vero cells expressing recombinant OAS or MX proteins. Afterwards, phosphorylation of eukaryotic initiation factor 2 alpha (eIF2alpha) was used to scale the degree of PKR activation upon infection of Vero cells by PI-3V. RESULTS: Overexpression of OAS did not result in significantly decreased viral replication. Phosphorylated eIF2alpha forms, the hallmark of PKR activation, were not increased in IFNalpha-primed infected Vero cells. Although human MXA contributed to partial blockade of replication of bovine PI-3V, the antiviral effect was not as strong as that of IFNalpha. CONCLUSIONS AND CLINICAL RELEVANCE: The powerful anti-Paramyxovirus activity of type 1 IFNs is mediated by noncanonic pathways. [less ▲]

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See detailExperimentally induced epizootic rabbit enteropathy: Clinical, histopathological, ultrastructural, bacteriological and haematological findings
Dewrée, Roxane; Meulemans, L.; Lassence, Cédric ULg et al

in World Rabbit Science (2007), 15(2, APR-JUN), 91-102

Epizootic rabbit enteropathy is an emerging disease that has appeared in French intensive enclosed rabbit farms since the beginning of 1997. Common clinical signs are mild watery diarrhoea with ... [more ▼]

Epizootic rabbit enteropathy is an emerging disease that has appeared in French intensive enclosed rabbit farms since the beginning of 1997. Common clinical signs are mild watery diarrhoea with considerable distension of the abdomen. At necropsy, a significant dilation of the stomach and small intestine without gross evidence of acute or chronic enteric lesions (inflammation or congestion) was observed. The purpose of this study was to describe the anatomopathologic changes concerning the small intestine and those concerning the blood profile, in experimentally infected rabbits. In a first part of the experiment, thirty animals were inoculated with a reference inoculum and five were kept as controls for clinical signs examination and histopathological study. In a second part, 17 out of the inoculated rabbits and the 5 controls animals were randomly assigned to blood testing. Microscopic lesions were studied in sections from the different parts of the small intestine (duodenum, jejunum and ileum) by light microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The histological findings revealed only limited inflammation in inoculated animals. Major villous changes were atrophy, fusion, destruction and loss of epithelial cells. In inoculated rabbits, the congestion and dilation of blood vessels of jejunal lamina propria were significantly higher than in control animals (P<0.005). There was significantly more (P<0.05) apoptosis of cells of the jejunal epithelium in inoculated rabbits than in control animals. Infiltration of polymorphonuclear neutrophiles was observed into the jejunal or ileal tunica muscularis. SEM performed on the intestinal tract of 15 inoculated rabbits revealed blankets and globular particles of mucus associated with numerous bacteria on jejunum and ileum villi. This was; not observed in the intestinal tract of control rabbits. Bacteria were found adhering to the epithelial surface and inside intestinal epithelial cells in a few animals by TEM and by light microscopy after Warthin-Starry staining. None of the bacteria isolated from the intestinal mixed contents and cultivated on usual media, are commonly known as rabbit's pathogens. Regarding the haernatological profile, neutrophil counts significantly increased (P<0.05) and lymphocyte counts significantly decreased (P<0.01), in inoculated rabbits compared to those of the control group. [less ▲]

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See detailDendritic cells genetically engineered to express IL-10 induce long-lasting antigen-specific tolerance in experimental asthma
Henry, E.; Desmet, C. J.; Garzé, V. et al

Poster (2007)

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See detailEvaluation de l’efficacité du Caprofène lors de bronchoneumonie expérimentale bovine à Mannheimia haemolytica
Wallemacq, Hugues; Boutet, Philippe; Zecchinon, L. et al

in Revue de Médecine Vétérinaire (2007), 158(8-9), 418-424

M. haemolytica serotype A1 (formerly known as Pasteurella) is the most important and commonly isolated bacterial pathogen from fatal cases of bovine fibrinous pleuroneumonia. M. haemolytica and its two ... [more ▼]

M. haemolytica serotype A1 (formerly known as Pasteurella) is the most important and commonly isolated bacterial pathogen from fatal cases of bovine fibrinous pleuroneumonia. M. haemolytica and its two principal toxins, the lipopolysaccharides (LPS) and the leukotoxin (LktA) induce the recruitment, the activation and the necrosis of neutrophils involved in the pathogenicity of bovine pneumonic mannheimiosis (BPM). The objective of this study was to determine whether systemic therapy with carprofène (Rimadyl®*), a non-steroidal anti-inflammatory drug, improves the disease development in an acute experimental model of BPM. The experimental pathology was induced by trans-tracheal inoculation of M. haemolytica and toxins at T0. One hour post-inoculation, six calves were treated intravenously with carprofen (1,4 mg/kg) while six placebo-treated calves received dose-matched volumes of sterile saline. The clinical and biochemical parameters were measured at one (T+1), three (T+3) and seven (T+7) hours after inoculation. Disease scores for carprofen treated calves were significantly lower than those for placebo-treated controls six hours (T+7) after treatment. These results were associated to a significantly oxygen saturation decrease at T+3 and a significantly blood lactate increase at T+7 in the control calves. Moreover, pulmonary lesions were significantly less extensive than those in the control group. Taken together, this finding suggest that pharmacological modulation by carprofen of pulmonary inflammation after appearance of acute BPM clinical signs leads to calves’ health enhancement and reduces the extent of gross pneumonic lesion. [less ▲]

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See detailCongenital muscular dystonia (CMD): a new congenital pathology in Belgian Blue calves
Vandeputte, Sébastien ULg; Brihoum, Mounir ULg; Hubin, Xavier et al

Conference (2006, October 15)

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See detailFlow cytometry for the follow-up of Trypanosoma evansi infection in a mouse model
Antoine-Moussiaux, Nicolas ULg; Leroy, ; Faisca, et al

Poster (2006, April)

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See detailGenomic structure, promoter analysis and expression of the porcine (Sus scrofa) TLR4 gene.
Thomas, Anne; Broers, Aurore ULg; Vandegaart, Hélène ULg et al

in Molecular Immunology (2006), 43(6), 653-659

Toll-like receptor 4 (TLR4) is essential for initiating the innate response to lipopolysaccharide (LPS) from Gram-negative bacteria by acting as a signal-transducing receptor. As the pig industry faces a ... [more ▼]

Toll-like receptor 4 (TLR4) is essential for initiating the innate response to lipopolysaccharide (LPS) from Gram-negative bacteria by acting as a signal-transducing receptor. As the pig industry faces a unique array of related pathogens, it is anticipated that the genotype of swine TLR4 could be of crucial importance in future strategies aimed at improving genetic resistance to infectious diseases. In order to help in investigating TLR4 as a candidate disease-resistance gene in pigs, we established its genomic structure and produced sufficient flanking intronic sequences to enable simple PCR amplification of the coding portions of the gene. Expression in different porcine tissues was studied and showed splicing variations in mRNA sequences. The cDNA sequence for poTLR4 contains an open reading frame of 2526bp that codes for 841 aa, 98 and 568bp in the 5'- and 3'-UTRs, respectively. Overall, the general organization of porcine, human, murine, and avian TLR4 genes is quite similar: three exons with the third one very long. A high level of conservation of the size and the sequence, especially for the two last exons and particularly in the sequence corresponding to the LRRs and TIR domain, is observed between species. The important antimicrobial properties of these proteins may account for a conservative selection pressure on these TLR4 coding sequences. Several putative binding sites described in the human and murine promoter of TLR4 genes have been identified in the 5'-flanking region of poTLR4. Conversely, this region lacks a TATA box, consensus initiator sequences, or GC-rich regions. The basic sequence data gathered will allow the establishment of an inventory of naturally occurring variation in porcine TLR4, so that alleles can be tested for disease association studies. [less ▲]

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See detailLes interférons de type 1 et leur fonction antivirale
Leroy, Michael; Desmecht, Daniel ULg

in Annales de Médecine Vétérinaire (2006), 150(2), 73-107

Type I interferons are part of the innate immune system involved in the first line defense against invasion, replication and spreading of pathogens such as viruses. Through specific membrane or ... [more ▼]

Type I interferons are part of the innate immune system involved in the first line defense against invasion, replication and spreading of pathogens such as viruses. Through specific membrane or intracellular receptors, virus entry induces the expression of type I interferons which stimulates the cells through an autocrine and paracrine manner. Interferons are polypeptides that stimulate cells through membrane receptors. They induce a cascade of events leading to the synthesis of many proteins some of which having specific antiviral properties. The most characterized are the MX proteins, the 2’5’ oligoadenylate synthetase/ ribonuclease L pathway and the double-stranded RNA-dependent protein kinase R system. Recently, the protein ISG20 has been involved in the specific antiviral function of type I interferons. The interferons act on multiple steps of the viral cycle including penetration, decapsidation, mRNA transcription, protein synthesis, genome replication, assembling and excretion of viral particles. Nowadays, due to their major efficiency, type I interferons are used in therapeutics against some viral infections and cancers. [less ▲]

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See detailEvaluation of systolic function in calves by Doppler echocardiography: preliminary results
Brihoum, M; Rollin, Frédéric ULg; Desmecht, Daniel ULg et al

in Proceedings of the XXIVth World Buiatrics Congress (2006)

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See detailExpression of the interferon-alpha/beta-inducible bovine Mx1 dynamin interferes with replication of rabies virus
Leroy, Michael; Pire, Grégory; Baise, Etienne ULg et al

in Neurobiology of Disease (2006), 21(3), 515-521

Rabies is a fatal anthropozoonotic viral infection of the central nervous system that remains a serious public health problem in many countries. As several animal cases of spontaneous survival to ... [more ▼]

Rabies is a fatal anthropozoonotic viral infection of the central nervous system that remains a serious public health problem in many countries. As several animal cases of spontaneous survival to infection were reported and because type 1 interferons were shown to protect against the virus, it was suggested that innate resistance mechanisms exist. Among the antiviral proteins that are synthesized in response to interferon-alpha/beta stimulation, Mx proteins from several species are long known to block the replication of vesicular stomatitis virus (VSV). As both VSV and rabies virus belongs to the Rhabdoviridae family, this study was started with the aim to establish whether the anti-VSV activity of a mammalian Mx protein could be extended to rabies virus. This question was addressed by inoculating the virus onto a bovine Mx1 or human MxA-expressing Vero cell clone. Plaque formation was unambiguously blocked, and viral yields were reduced 100- to 1000-fold by bovine Mx1 expression for both SAG2 and SADB19 viral strains. In opposition, only SAG2 strain could be inhibited by the expression of human MxA protein. The effect of both proteins expression was then evaluated at the viral protein expression level. Again, boMx1 was able to repress protein expression in both strain, whereas only SAG2 proteins were inhibited in human MxA-expressing cells. These results suggest that protection conferred by interferon-alpha/beta against rabies could be, at least partially, attributable to the Mx pathway. Alternatively, bovine Mx1 could be unique in its ability to repress rabies virus which, if confirmed in vivo, would open an avenue for the development of new antirabies therapeutic strategies. [less ▲]

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See detailDifferential resistance/susceptibility patterns to pneumovirus infection among inbred mouse strains
Bui Tran Anh, Dao; Faisca, Rui-Pedro; Desmecht, Daniel ULg

in American Journal of Physiology - Lung Cellular and Molecular Physiology (2006), 291

Respiratory syncytial virus (RSV) is a prominent cause of airway morbidity in children under 1 yr of age. It is assumed that host factors influence the severity of the disease presentation and thus the ... [more ▼]

Respiratory syncytial virus (RSV) is a prominent cause of airway morbidity in children under 1 yr of age. It is assumed that host factors influence the severity of the disease presentation and thus the need for hospitalization. As a first step toward the identification of the underlying genes involved, this study was undertaken to establish whether inbred mouse strains differ in susceptibility to pneumonia virus of mice (PVM), the murine counterpart of RSV, which has been shown to accurately mimic the RSV disease of children. With this purpose in mind, double-chamber plethysmography and carbon monoxide uptake data were collected daily for 7 days after inoculation of PVM in six inbred strains of mice. In parallel, histological examinations and lung viral titration were carried out from day 5 to day 7 after inoculation. Pulmonary structure/function values reflected the success of viral replication in the lungs and revealed a pattern of continuous variation, with resistant, intermediate, and susceptible strains. The results suggest that SJL (resistant) and 129/Sv (susceptible) strains should be used in crossing experiments aimed at identifying genes controlling pneumovirus replication by the positional cloning approach. Similarly, crossing experiments using BALB/c or C57BL/6 (resistant) and DBA/2 or 129/Sv (susceptible) will allow the identification of the genes involved in the control of pulmonary inflammation during pneumovirus infection. [less ▲]

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See detailKey roles of LFA-1 in leukocyte migration and immune response
Zecchinon, Laurent ULg; Fett, Thomas ULg; Vanden Bergh, Philippe ULg et al

in Clinical & Applied Immunology Reviews (2006), 6

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See detailAnatomy of the Lymphocyte function-associated antigen-1
Zecchinon, Laurent ULg; Fett, Thomas ULg; Vanden Bergh, Philippe ULg et al

in Clinical & Applied Immunology Reviews (2006), 6

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See detailGenomic structure, promoter analysis, and expression of the porcine (Sus scrofa) Mx1 gene
Thomas, Anne; Palm, Mélanie; Broers, Aurore ULg et al

in Immunogenetics (2006), 58

Allelic polymorphisms at the mouse Mx1 locus affect the probability of survival after experimental influenzal disease, raising the possibility that marker-assisted selection using the homologous locus ... [more ▼]

Allelic polymorphisms at the mouse Mx1 locus affect the probability of survival after experimental influenzal disease, raising the possibility that marker-assisted selection using the homologous locus could improve the innate resistance of pigs to natural influenza infections. Several issues need to be resolved before efficient large scale screening of the allelic polymorphism at the porcine (Sus scrofa) Mx1 locus can be implemented. First, the Mx1 genomic structure has to be established and sufficient flanking intronic sequences have to be gathered to enable simple PCR amplification of the coding portions of the gene. Then, a basic knowledge of the promoter region needs to be obtained as an allelic variation there can significantly alter absolute levels and/or tissue-specificity of MX protein expression. The results gathered here show that the porcine Mx1 gene and promoter share the major structural and functional characteristics displayed by their homologs described in cattle, mouse, chicken, and man. The crucial function of the proximal interferon-sensitive response elements motif for gene expression is also demonstrated. The sequence data compiled here will allow an extensive analysis of the polymorphisms present among the widest spectrum possible of porcine breeds with the aim to identify an Mx1 allele providing antiviral resistance. [less ▲]

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See detailLFA-1 and associated diseases: the dark side of a receptor
Zecchinon, Laurent ULg; Fett, Thomas ULg; Vanden Bergh, Philippe ULg et al

in Clinical & Applied Immunology Reviews (2006), 6

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See detailBind another day: the LFA-1/ICAM-1 interation as therapeutic target
Zecchinon, Laurent ULg; Fett, Thomas ULg; Vanden Bergh, Philippe ULg et al

in Clinical & Applied Immunology Reviews (2006), 6

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See detailSuppression of pattern recognition receptor TLR4 sensing does not alter lung responses to pneumovirus infection
Faisca, Pedro; Bui Tran Anh, Dao; Thomas, Anne et al

in Microbes & Infection (2006), 8

Toll-like receptors (TLR) are an important component in the innate immune response to a wide variety of pathogens. Recently, a series of studies has addressed the hypothesis that TLR4 also participates in ... [more ▼]

Toll-like receptors (TLR) are an important component in the innate immune response to a wide variety of pathogens. Recently, a series of studies has addressed the hypothesis that TLR4 also participates in the host innate response against respiratory syncytial virus (RSV), the leading cause of lower respiratory tract infections in infants and young children. In most of the studies available, RSV, which is not a natural pathogen of mice, has been systematically used in mouse models of human bronchiolitis, with conflicting results. Pneumonia virus of mice (PVM), a member of the pneumovirus genus, shares many similarities with RSV. The serological and structural relationships that exist between them suggest that the immune response to these viruses may be similar in their respective natural hosts. To determine the role of TLR4 in host defense against PVM, TLR4-competent and TLR4-deficient mice were intranasally infected with PVM. Variation of body weight, pulmonary function values, histopathology, and pulmonary viral loads were analyzed. None of the investigated clinical, functional, histological and virological parameters was different between strains, which demonstrates that the sensitivity of the mouse to its natural pneumovirus infection is independent of the presence or absence of TLR4 sensing. [less ▲]

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