La vaccination contre les mammites à Staphylococcus aureus chez la vache laitière

in Annales de Médecine Vétérinaire (2010), 154(1), 16-29

Staphylococcus (S.) aureus is a major pathogen for mastitis in dairy cattle. In most cases, S. aureus causes long-lasting subclinical and chronic bovine mastitis and leads to significant economic losses ... [more ▼]

Staphylococcus (S.) aureus is a major pathogen for mastitis in dairy cattle. In most cases, S. aureus causes long-lasting subclinical and chronic bovine mastitis and leads to significant economic losses by reducing the quantity and the quality of the milk produced. The pathogenesis of S. aureus mastitis includes the ability to persist within host cells and involves multiple virulence factors including toxins, surface proteins and polysaccharides. The numerous vaccines that have been developed induce a specific immune response against these different factors. These different vaccine approaches are described and classified depending on the target antigen used. Moreover, some recent vaccine strategies against human S. aureus infections are also discussed and could eventually be used for the design of new bovine vaccines. Although most of bovine vaccines induce specific humoral response, to date, no vaccine has been described to protect efficiently against experimental and naturally occurred bovine S. aureus mastitis. In conclusion, this type of immune response and the broad antigenic variability of S. aureus strains can partially explain the lack of protection observed during most of vaccine trials. [less ▲]

Veterinary education curriculum: basic sciences

Conference given outside the academic context (2009)

Lung interstitial macrophages alter dendritic cell functions to prevent airway allergy in mice

in Journal of Clinical Investigation (2009), 119(12), 3723-38

The respiratory tract is continuously exposed to both innocuous airborne antigens and immunostimulatory molecules of microbial origin, such as LPS. At low concentrations, airborne LPS can induce a lung DC ... [more ▼]

The respiratory tract is continuously exposed to both innocuous airborne antigens and immunostimulatory molecules of microbial origin, such as LPS. At low concentrations, airborne LPS can induce a lung DC-driven Th2 cell response to harmless inhaled antigens, thereby promoting allergic asthma. However, only a small fraction of people exposed to environmental LPS develop allergic asthma. What prevents most people from mounting a lung DC-driven Th2 response upon exposure to LPS is not understood. Here we have shown that lung interstitial macrophages (IMs), a cell population with no previously described in vivo function, prevent induction of a Th2 response in mice challenged with LPS and an experimental harmless airborne antigen. IMs, but not alveolar macrophages, were found to produce high levels of IL-10 and to inhibit LPS-induced maturation and migration of DCs loaded with the experimental harmless airborne antigen in an IL-10-dependent manner. We further demonstrated that specific in vivo elimination of IMs led to overt asthmatic reactions to innocuous airborne antigens inhaled with low doses of LPS. This study has revealed a crucial role for IMs in maintaining immune homeostasis in the respiratory tract and provides an explanation for the paradox that although airborne LPS has the ability to promote the induction of Th2 responses by lung DCs, it does not provoke airway allergy under normal conditions. [less ▲]

Le microdamier: un outil du futur pour le diagnostic de l’inflammation ?

Poster (2009)

Comment investiguer la contre-performance d’origine médicale : de la clinique au laboratoire

in 35ème Journée de la Recherche équine (2009)

Clinical affections of the locomotor and respiratory systems are the two main causes of poor performance in sport horses. Nevertheless, each subclinical affection of any system implicated in the oxygen ... [more ▼]

Clinical affections of the locomotor and respiratory systems are the two main causes of poor performance in sport horses. Nevertheless, each subclinical affection of any system implicated in the oxygen system (respiratory, cardiovascular, blood, muscular and metabolic) may also become a limiting factor concerning the athletic capacities of the horse. A systematic medical examination of the horse, combining ail the clinical and laboratory exams, is thus necessary in order to establish a precise and comprehensive diagnosis regarding the different affections. The objectives of this communication are therefore to present the different methods currently available for the practitioner as well as the techniques recently developed for horses. The complementarity of the different clinical and laboratory exams, as well as the ideal moment for performing each test are clarified in order to accurately determine the different causes of poor performance as well as their functional repercussions [less ▲]

Effects of betamethasone on inflammation and emphysema induced by cadmium nebulisation in rats

in European Journal of Pharmacology (2009), 606(1-3), 210-214

Cadmium (Cd) induces centrilobular emphysema and is suspected to contribute to tobacco related lung diseases as chronic obstructive pulmonary disease (COPD). This study aimed to check whether the ... [more ▼]

Cadmium (Cd) induces centrilobular emphysema and is suspected to contribute to tobacco related lung diseases as chronic obstructive pulmonary disease (COPD). This study aimed to check whether the inflammatory process observed in rats exposed to nebulised Cd is resistant to betamethasone as observed in COPD and to determine the influence of this drug on airspace enlargement together with the MMP-2-9/TIMP-1-2 imbalance. Our results showed that betamethasone induced emphysema by itself in healthy rats. Moreover, pre-treatment of rats with betamethasone could only partially modulate the increase in bronchoalveolar lavage fluid cell counts and the absence of preventive effect of this compound against emphysema development is associated with its inability to rebalance the MMP-2-9/TIMP-1-2 ratio. [less ▲]

Influence of subclinical inflammatory airway disease on equine respiratory function evalueated by impulse oscillometry

in Equine Veterinary Journal (2009), 41(4), 384-389

Reasons for performing study: Inflammatory airway disease (IAD) is a nonseptic condition of the lower respiratory tract. Its negative impact on respiratory function has previously <br /><br />been ... [more ▼]

Reasons for performing study: Inflammatory airway disease (IAD) is a nonseptic condition of the lower respiratory tract. Its negative impact on respiratory function has previously <br /><br />been described using either forced expiration or forced oscillations techniques. However, sedation or drug-induced bronchoconstriction were usually required. The impulse <br /><br />oscillometry system (IOS) is a noninvasive and sensitive respiratory function test validated in horses, which could be useful to evaluate IAD-affected horses without further <br /><br />procedures. <br /><br />Objectives: To determine the sensitivity of IOS in detecting alterations of the respiratory function in subclinically IAD-affected horses without inducing bronchoprovocation and to characterise their respiratory impedance according to frequency for each respiratory phase. <br /><br />Methods: Pulmonary function was evaluated at rest by IOS in 34 Standardbred trotters. According to the cytology of bronchoalveolar lavage fluid (BALF), 19 horses were defined <br /><br />as IAD-affected and 15 horses were used as control (CTL). Total respiratory resistance (Rrs) and reactance (Xrs) from 1–20 Hz as well as their inspiratory and expiratory <br /><br />components were compared between groups. <br /><br />Results: A significant increase of Rrs at the lower frequencies (R1–10 Hz) as well as a significant decrease of Xrs beyond 5 Hz (X5–20 Hz) was observed in IAD compared to CTL horses. IOS-data was also significantly different between inspiration and expiration in IAD-affected horses. In the whole population, both BALF eosinophil and mast cell counts were <br /><br />significantly correlated with IOS measurements. <br /><br />Conclusions: Functional respiratory impairment may be measured, even in the absence of clinical signs of disease. In IAD-affected horses, the different parameters of respiratory <br /><br />function (Rrs or Xrs) may vary depending on the inflammatory cell profiles represented in BALF. <br /><br />Potential relevance: Impulse oscillometry could be used in a routine clinical setting as a noninvasive method for early detection of subclinical respiratory disease and of the results <br /><br />of treatment in horses. [less ▲]

IRF3 is required for the induction of allergic airway inflammation by lung dendritic cells in a mouse model of house dust mite-induced atopic asthma

in Abstracts of the 17th Annual European Respiratory Society Congress, Vienna, Austria (2009)

Essential role of sirtuins in the pathogenesis of allergic airway inflammation

in Short book of the Annual Congress of the European Respiratory Society (ERS), Vienne (2009)

Characterization of pentraxin 3 in the horse and its expression in airways.

in Veterinary Research (2009), 41(2), 18

The long pentraxin 3 (PTX3) plays an important role in host defence and its over-expression may contribute to airway injury. The aim of the present study was therefore to characterize in more detail PTX3 ... [more ▼]

The long pentraxin 3 (PTX3) plays an important role in host defence and its over-expression may contribute to airway injury. The aim of the present study was therefore to characterize in more detail PTX3 and its expression in the horses airway. Six healthy horses and six horses affected by recurrent airway obstruction (R.A.O.) were submitted to a dusty environment challenge. PTX3 DNA and cDNA were cloned and sequenced. PTX3 expression was evaluated by RT-qPCR, western blotting and immuno-histochemistry in bronchoalveolar lavage fluid (BALF) cells, BALF supernatant and bronchial epithelial cells. An alternative splicing of the second exon of PTX3 occurred, resulting in two forms of the protein: spliced (32 kDa) and full length (42 kDa). PTX3 was detected in BALF macrophages, neutrophils and bronchial epithelial cells. It was over-expressed in the BALF supernatant from R.A.O.-affected horses in crisis. However, dust was unable to induce PTX3 in BALF cells ex vivo, indicating that dust is an indirect inducer of PTX3. Dust exposure in-vivo induced PTX3 in BALF macrophages but there was no significant difference between healthy and R.A.O.-affected horses. Conversely, PTX3 was over-expressed in the bronchial epithelial cells from R.A.O-affected horses in crisis. These data indicate a differential regulatory mechanism in inflammatory and bronchial epithelial cells and offer therapeutically interesting perspectives. [less ▲]