| 摘要 |
<p>The present invention relates to live PRRS viruses which are attenuated by amino acid mutations in a specific site of the viral protein coded by the open reading frame (ORF) selected from the group of ORF 1a, ORF 1b and/or ORF 2. The invention also pertains to nucleotide sequences coding said viruses, methods of generating such viruses and their use for the preparation of a pharmaceutical composition for the prophylaxis and treatment of PRRS infections.</p> |
