| 摘要 |
The present invention relates to detoxified immunogenic derivatives of Clostridium perfringens beta -toxin or an immunogenic fragment thereof that have as a characteristic that they carry a mutation in the beta -toxin amino acid sequence, not found in the wild-type beta -toxin amino acid sequence. The invention also relates to genes encoding such beta -toxins, as well as to expression systems expressing such beta -toxins. Moreover, the invention relates to bacterial expression systems expressing a native beta -toxin. Finally, the invention relates to vaccines based upon detoxified immunogenic derivatives of Clostridium perfringens beta -toxin, and methods for the preparation of such vaccines. |
