Pseudorabies Vaccine shall be prepared from virus-bearing cell culture fluids. Only Master Seed which has been established as pure, safe, and immunogenic shall be used for preparing seeds for vaccine production. All serials of vaccine shall be prepared from the first through the fifth passage from the Master Seed.
CFR 9-113.318-2014 history
2014CFR 9-113.318-2014 Animals and animal products. Part113:Standard requirements. Section113.318:Pseudorabies Vaccine.