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  Helenalin reduces Staphylococcus aureus infection in vitro and in vivo; ; et al in Veterinary Microbiology (2007), 119(2-4), 330-338 Staphylococcus (S.) aureus is a major udder pathogen causing bovine mastitis. Some pro-inflammatory cytokines, including tumor necrosis factor-alpha (TNF-alpha), enhance extracellular and intracellular ... [more ▼] Staphylococcus (S.) aureus is a major udder pathogen causing bovine mastitis. Some pro-inflammatory cytokines, including tumor necrosis factor-alpha (TNF-alpha), enhance extracellular and intracellular growth of S. aureus, indicating that the inflammatory process favors S. aureus infection. Helenalin is a sesquiterpene lactone with potent anti-inflammatory properties. This study was designed to evaluate the effects of helenalin on S. aureus infection. First, in vitro experiments were conducted. These studies revealed that proliferation of S. aureus in bovine mammary epithelial MAC-T cells treated in the presence or absence of TNF-alpha was markedly reduced in the presence of helenalin. Secondly, in vivo effects of helenalin were investigated. Lactating mice treated in the presence or absence of helenalin were challenged by the intramammary route with S. aureus and the bacteria in the mammary glands were counted 12 h after infection. Significantly less numbers of bacteria were recovered from the infected glands of helenalin-treated mice compared with untreated mice. Moreover, histological examination of mammary tissue from helenalin-treated mice that were challenged with S. aureus indicated that helenalin is able to significantly reduce leukocyte infiltration in the mammary gland following S. aureus inoculation. Our results show that helenalin reduces S. aureus intracellular growth and experimental S. aureus infection. We conclude that helenalin may be of potential interest in the treatment of S. aureus-induced mastitis in the bovine species. [less ▲] Detailed reference viewed: 77 (18 ULg)Nuclear factor kappaB inhibition in bovine mammary epithelial cells reduces intracellular infection by Staphylococcus aureus.; Bureau, Fabrice  ; Lekeux, Pierre in Proceedings : 23rd World Buiatrics Congress (2004) Detailed reference viewed: 14 (2 ULg)Delayed neutrophil apoptosis in bovine subclinical mastitis.Boutet, Philippe ; ; Gillet, Laurent et alin 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: 48 (13 ULg)Increased nuclear Factor kappa B activity in milk cells of mastitis-affected cows; Bureau, Fabrice ; et alin Journal of Dairy Science (2003), 86(4), 1259-1267 Bacterial mastitis is accompanied by a drastic increase in milk somatic cell count (SCC), with neutrophils being the predominant cell type found in the infected quarters. Accumulation and activation of ... [more ▼] Bacterial mastitis is accompanied by a drastic increase in milk somatic cell count (SCC), with neutrophils being the predominant cell type found in the infected quarters. Accumulation and activation of neutrophils at the site of infection require local expression of many inflammatory genes encoding adhesion molecules, chemokines and cytokines. Most of the inflammatory genes contain binding sites for the nuclear factor kappaB (NF-kappaB) within their promoter and therefore partly depend on NF-kappaB for their expression. We thus hypothesized that an increase in NF-kappaB activity in the mammary gland could contribute to development of the neutrophilic inflammation that characterizes mastitis. In an attempt to verify this hypothesis, we first assessed milk cells from healthy and acute and chronic mastitis-affected cows for NF-kappaB activity using electrophoretic mobility shift assays. We next studied the relationships between the intensity of NF-kappaB activity in these cells and the degree of udder inflammation. Active NF-kappaB complexes were undetectable in milk cells from healthy cows, whereas high levels of NF-kappaB activity were always found in cells from cows with acute mastitis. In milk cells obtained from chronic mastitis-affected cows, NF-kappaB activity varied from low to high. Finally, the level of NF-kappaB activity measured in milk cells from chronic mastitis-affected cows was not correlated to SCC or to the proportion of neutrophils present in milk samples, but was highly correlated with the expression level of interleukin-8 and granulocyte/macrophage colony-stimulating factor, two NF-kappaB-dependent cytokines crucially involved in initiation and perpetuation of neutrophilic inflammation. These results suggest that NF-kappaB might play a role in mastitis pathogenesis. [less ▲] Detailed reference viewed: 36 (25 ULg)NF-kB activity, and IL-8 and GM-CSF expression, in the milk of chronic mastitis-affected cows; Bureau, Fabrice ; Lekeux, Pierre in Proceedings : National Mastitis Council, 41st Annual Meeting (2002) Detailed reference viewed: 13 (4 ULg)Mécanismes de l'inflammation subclinique de la glande mammaireLekeux, Pierre ; ; Boutet, Philippe et alin Proceedings : Congrès de la Société française de Buiatrie "Actualités en Buiatrie" (2001) Detailed reference viewed: 82 (5 ULg)Le virus de la diarrhee virale bovine et de la maladie des muqueuses (BVD/MD): diagnostic et comportement epidemiologique et biologiquePastoret, Paul-Pierre ; ; et alReport (1999) Detailed reference viewed: 8 (0 ULg)Le virus de la diarrhée virale bovine et de la maladie des muqueuses (BVD/MD): diagnostic et comportement épidémiologique et biologiquePastoret, Paul-Pierre ; ; et alReport (1998) Detailed reference viewed: 15 (2 ULg)Transmission du virus BVD/MD et aspects épidémiologiques de l'infection; ; Mignon, Bernard et alin Bulletin des Groupements Techniques Vétérinaires (1993), 4 Detailed reference viewed: 25 (0 ULg)Le portage asymptomatique des Pestivirus chez les ruminantsPastoret, Paul-Pierre ; ; Mignon, Bernard et alin Revue Scientifique et Technique (International Office of Epizootics) (1992), 11(4), 1087-1096 Pestiviruses are enveloped single-chain ribonucleic acid viruses with a positive polarity. Pestiviruses include the viruses of classical swine fever (hog cholera), Border disease of sheep, mucosal disease ... [more ▼] Pestiviruses are enveloped single-chain ribonucleic acid viruses with a positive polarity. Pestiviruses include the viruses of classical swine fever (hog cholera), Border disease of sheep, mucosal disease of cattle, and isolates obtained from wild animals, such as red deer (Cervus elaphus). Among ruminants, pestiviruses have developed a remarkable strategy for assuring their persistence. Through epigenetic transmission, they lead to the birth of asymptomatic carrier animals harbouring non-cytopathic variants, which become immunotolerant to the strain of virus present. The presence of a small number of asymptomatic carriers enables the virus to circulate within a herd by horizontal transmission, leading to the birth of a new generation of asymptomatic carriers. [less ▲] Detailed reference viewed: 27 (1 ULg)Epidemiological Evaluation of a Monoclonal Elisa Detecting Bovine Viral Diarrhoea Pestivirus Antigens in Field Blood Samples of Persistently Infected CattleMignon, Bernard ; ; Thiry, Etienne et alin Journal of Virological Methods (1992), 40(1), 85-93 An enzyme-linked immunosorbent assay (ELISA), using monoclonal antibodies for capture and detection, was developed for detecting bovine viral diarrhoea virus (BVDV) antigens in blood samples. The test was ... [more ▼] An enzyme-linked immunosorbent assay (ELISA), using monoclonal antibodies for capture and detection, was developed for detecting bovine viral diarrhoea virus (BVDV) antigens in blood samples. The test was evaluated using 761 field samples of known status (viraemic or not). When an appropriate cut-off value was chosen, the sensitivity, specificity, and predictive values of the assay were 100%, higher than the values obtained by classical virus isolation. Correlation with the latter technique exceeded 90%. The ELISA is a good candidate for replacing virus isolation as a reference method for BVDV antigen detection in persistently infected carriers. A method based on the mean of the standard deviation ratio can be used to choose the cut-off value in order to optimise reproducibility. [less ▲] Detailed reference viewed: 8 (1 ULg)Epidémiologie, pathogénie et aspects cliniques des troubles provoqués par le virus de la diarrhée virale bovine/maladie des muqueuses; Mignon, Bernard ; et alConference (1992) Detailed reference viewed: 5 (1 ULg)Données récentes sur la biologie moléculaire du pestivirus responsable de la maladie des muqueuses (BVD/MD); Mignon, Bernard ; et alin Annales de Médecine Vétérinaire (1992), 136 Detailed reference viewed: 21 (1 ULg)Bilan de cinq années de détection des taurillons infectés de manière persistante par le virus BVD au centre de sélection bovine de Ciney; ; et al in Annales de Médecine Vétérinaire (1992), 136 Detailed reference viewed: 13 (1 ULg)A Monoclonal Elisa for Bovine Viral Diarrhoea Pestivirus Antigen Detection in Persistently Infected CattleMignon, Bernard ; ; et alin Journal of Virological Methods (1991), 35(2), 177-188 Detection of cattle persistently infected with bovine viral diarrhoea virus (BVDV) is crucial to controlling mucosal disease. A sandwich enzyme-linked immunosorbent assay (ELISA) using monoclonal ... [more ▼] Detection of cattle persistently infected with bovine viral diarrhoea virus (BVDV) is crucial to controlling mucosal disease. A sandwich enzyme-linked immunosorbent assay (ELISA) using monoclonal antibodies raised against the 48-kDa glycoprotein and the 120/80-kDa protein was developed for detecting antigens in leucocytes of 3 persistently BVDV-infected calves. The test is simple, sensitive and rapid. Moreover the same ELISA was able to recognise Belgian field isolates of BVDV. These results show that the test can be applied in the field. [less ▲] Detailed reference viewed: 12 (1 ULg)Characterization of Monoclonal Antibodies to Bovine Viral Diarrhoea Virus: Evidence of a Neutralizing Activity against Gp48 in the Presence of Goat Anti-Mouse Immunoglobulin Serum; ; et al in Journal of General Virology (1991), 72(5), 1195-1198 Twenty-one monoclonal antibodies (MAbs) directed against the NY-1 and the Osloss-c strains of bovine viral diarrhoea virus were produced and characterized by indirect immunofluorescence assay ... [more ▼] Twenty-one monoclonal antibodies (MAbs) directed against the NY-1 and the Osloss-c strains of bovine viral diarrhoea virus were produced and characterized by indirect immunofluorescence assay, radioimmunoprecipitation and neutralization tests. Fourteen MAbs directed against the NY-1 strain recognized the gp48 and showed a weak neutralizing activity in the presence of goat anti-mouse immunoglobulin serum. [less ▲] Detailed reference viewed: 2 (1 ULg)Variations de l'antigéniémie dans l'infection persistante des bovins par le virus de la diarrhée virale bovine (BVD); Mignon, Bernard ; et alin Annales de Médecine Vétérinaire (1991), 135 Detailed reference viewed: 5 (1 ULg)Le portage asymptomatique des pestivirusPastoret, Paul-Pierre ; Mignon, Bernard ; et alin Revue scientifique et technique de l'Office international des Epizooties (1991), 11(4), 1087 Detailed reference viewed: 2 (0 ULg)Impact des biotechnologies en santé animalePastoret, Paul-Pierre ; Thiry, Etienne ; et alReport (1990) Detailed reference viewed: 4 (1 ULg)Neutralization of Bovine Herpesvirus Type 4 by Pairs of Monoclonal Antibodies Raised against Two Glycoproteins and Identification of Antigenic Determinants Involved in Neutralization; ; et al in Journal of General Virology (The) (1990), 71((Pt 3)), 647-53 In infected cattle, bovine herpesvirus type 4 (BHV-4) induces an immune response with low neutralizing antibody levels or in the absence of such antibodies. For the study of this phenomenon, monoclonal ... [more ▼] In infected cattle, bovine herpesvirus type 4 (BHV-4) induces an immune response with low neutralizing antibody levels or in the absence of such antibodies. For the study of this phenomenon, monoclonal antibodies (MAbs) raised against two BHV-4 glycoproteins identified previously (150K/120K/51K and 120K/16.5K) were used in neutralization tests. None of the MAbs except for MAb 16 could neutralize alone; pairs of MAbs against the 150K/120K/51K and 120K/16.5K glycoproteins were able to neutralize BHV-4 infectivity. MAbs involved in neutralization were used in competitive binding assays to identify epitopes relevant for BHV-4 neutralization. These MAbs showed a low avidity and a weak neutralizing activity, and they partially decreased BHV-4 attachment to cells. These results suggest that the BHV-4 glycoprotein domains involved in viral infectivity are poorly exposed to the immune system. [less ▲] Detailed reference viewed: 10 (0 ULg)
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