Description: Making an adenovirus with traditional recombinant methods takes 2-3 months and requires tedious plaque recombination. More recent technologies have shortened this time somewhat, but still produce relatively high amounts of wild type (replication-competent) plaques, levels of which increase with serial amplification. The RAPAd® Adenoviral Expression Systems produce recombinant adenovirus with substantially reduced wild-type virus, while considerably shortening the production time to 2-3 weeks. Serial amplification of adenovirus produced using the RAPAd® system does not significantly increase replication-competent adenovirus levels. The system uses a backbone vector from which the 5' ITR, packaging signal and E1 sequences have been removed.