Adenovirus

Adenoviral vectors have a number of positive aspects. They infect dividing and non-dividing cells. Adenovirus has transient high-level protein expression, and it can accommodate inserts of up to 8 kb. Larger inserts can be added, provided that an equivalent part of the viral genome has been properly deleted. High viral titer can be produced (1x10¹² pt/ml (1x10¹⁰ pfu/ml) to 1x10¹³ pt/ml (1x10¹¹ pfu/ml).

The University of Iowa Gene Transfer Vector Core (GTVC) has developed the RAPAd^TM system (U.S. Patent No. 6,830,920 B2). A description of the system can be found in "A simple method for the rapid generation of recombinant adenovirus vectors" published in Gene Therapy 7:1034-1038, 2000. This system eliminates problems in standard adenoviral production. The RAPAd^TM construction plasmids have left-hand ITR, packaging signal, E1a, and partial E1b sequence deletions which greatly reduce wild type occurrence in the vectors. There is, therefore, no time-consuming plaque purification step involved. Every virus is tested for wild type by a PCR amplification of E1 sequences and an A549 plaque assay. These vectors are ready within one month, literally cutting production time in half relative to other methods.

The RAPAd^TM offers a number of backbones which encode a separate reporter expression cassette, thus allowing ease in tracking infection efficiency and spread.