We previously shown that adenylate cyclase-hemolysin (AC-Hly) toxin, secreted by B. pertussis, is responsible in vivo and in vitro of alveolar macrophages death via apoptosis but is not cytotoxic for epithelial cells. For this reason we made the hypothesis that a specific receptor for AC-Hly exists on the macrophage surface. In fact, using different specific antibodies we recently showed that the integrin Mac-1 is the receptor of AC-Hly. Since epithelial cells do not express Mac-1, they are resistant to AC-Hly toxin.

It was important using confocal microscopy and immunofluorescence labelling what was the AC-Hly localisation inside the macrophage. Our results show that after fixation on its receptor AC-Hly enters the cell by macropinocytosis. This mechanim is required for AC-Hly cytotoxic activity.

Epithelial cell plays a role in the recrutment of inflammary cells via cytokines secretion. For this reason our aim is to analyse which cytokines are secreted by human tracheal epithelial cells infected by B. pertussis or in contact with purified toxins or adhesins. Our preliminary results show that B. pertussis strains induce IL-6 secretion while there is no induction or inhibition of secretion of IL-8.

The study is performed in vivo using our murine respiratory model and in vitro. Is the target cell a dendritic leukocyte ? Our first results indicate the recruitment of dendritic leucocytes in the pulmonary parenchymus and bronchoalveolar fluid early after infection as well as the presence of intracellular bacteria.

In France, since several years a resurgence of whooping cough is observed with infants contamined by adolescents and adults. In order to confirm this epidemiology we undertook with 80 general practitioners, a study to determine the prevalence of whooping cough in adults, describe the clinical symptoms during the disease and evaluate the ability of biological diagnosis such as culture, PCR and serology to diagnose the disease in adult. A prevalence of 32 % was found. All confirmed case were characterized by : a higher frequency of work stops, cough with whoops PCR on experations is a more sensitive diagnosis than culture. Measurement of anti-pertussis toxin IgG and IgA by ELISA seems also a very useful diagnosis.

Our murine intranasal model, was used to compare the ability of different whole cell and acellular vaccines. Till now, all vaccines are able to induce a protective immunity against infections due to different variants.

The new epidemiology in countries using generalized vaccination since many years is characterized by an increase in new-born mortality (too young to be vaccinated) contaminated by adolescents or adults whom immunity waned with time. The use of specific antibodies able to neutralize toxins and adhesins activities could be a useful tool to decrease symptoms during infection and to stop transmission of the bacteria. For these reason we tested the ability of different antibodies to decrease symptoms after Bordetella infections using our respiratory murine model.

B. bronchiseptica is a respiratory pathogen for many mamals species, including human. In human, B. bronchiseptica is considered as an opportunist pathogen for immunodepressed patient or patient with respiratory problems. We previously described that this bacterium can induce chronic infections. We confirmed the zoonotic character of this infection with two patients contaminated with either infected rabbit or dog. Furthermore, samples from dogs showed that the bacterium can be isolated on vaccinated dogs.

Studies will continue because of the increase of immunocompromised patients, absence of cross protection of new pertussis vaccine, low efficacy of veterinary vaccines and antibiotic resistances carried by this bacterium.

The missions of this Centre is to confirm the identification of Bordetella isolates collected in France, to maintain the collection, to teach French bacteriologists, to analyse isolates by Pulsed-Field-Gel Electrophoresis, as well as the toxins and adhesins they express, to set up sensitive and specific biological diagnosis techniques and to be part of the National surveillance net, RENACOQ, coordinated by the Ministery of Health.

The set up of procedures and quality insurance in the laboratory was pursued.