Highly suppressible expression of single-chain interleukin-12 by doxycycline following adenoviral infection with a single-vector Tet-regulatory system.

Background: Adenoviral vectors have been shown to efficiently transfer DNA into a wide variety of eukaryotic cells in vitro and in vivo. However, the therapeutic benefit of this approach is limited by severe side effects as a result of uncontrolled transgene expression.

Methods: A bi-directional promoter that controls the desired transgene as well as a tetracycline-suppressible transactivator (tTA) was cloned into the E1-region of E1-deleted recombinant adenoviral vectors.