| 摘要 |
<p>1481847 Marek's disease vaccine M SEVOIAN 17 July 1974 [19 July 1973] 31643/74 Heading A5B A process for preparing a vaccine for immunising poultry against Marek's disease comprises producing a virulent strain of Marek's disease virus, identified as JM-V strain, by the multiple serial passage of JM Marek's disease virus through live chickens to obtain a highly pathogenic and immunogenic virus, and then attenuating the pathogenic material so obtained by serially passing the same through an avian embryo and a number of further passages through avian cells in vivo or in vitro until the resulting material becomes non-pathogenic or substantially so but remains highly immunogenic to Marek's disease virus.</p> |
