| abstract |
The present invention relates to live Bordetella strains which are deficient in the production of B. perfussis PTX toxin and, where appropriate, dermonecrotic toxin DNT, as well as in the release of cytotracheal toxin TCT, by attenuation. genetics, in particular by mutation or deletion of the ptx gene and, where appropriate, of the dnf gene, and by insertion of a strong promoter upstream of the gene coding for the AmpG protein, which is involved in the recycling of the TCT toxin. The present invention also relates to methods for obtaining these strains, as well as their use for the preparation of vaccines. Finally, the invention relates to immunogenic compositions comprising such strains. |