Localized adenovirus gene delivery using antiviral IgG complexation

Gene therapy with viral vectors has progressed to clinical trials. However, the localization of viral vector delivery to diseased target sites remains a challenge. We tested the hypothesis that an adenoviral vector could be successfully delivered by complexation with a specific antibody that is bound to a biodegradable matrix designed for achieving localized gene transduction. We report the first successful delivery system based upon antibody immobilization of virions in a type I collagen-avidin gel using a polyclonal biotinylated IgG specific for the adenovirus hexon. In vitro stability studies demonstrated retention of viral vector activity with antibody-complexed adenovirus collagen gel preparations, in comparison to loss of vector activity from collagen gels prepared with nonspecific biotinylated IgG. Cell culture investigations using this antibody-controlled release system for adenoviral vector transduction of rat aortic smooth muscle cells (A10) demonstrated a significantly more localized reporter expression (beta-galactosidase) compared with non-antibody-complexed controls. Herpes simplex thymidine kinase (HSVtk) adenoviral vectors were immobilized on avidin-collagen gels via this antibody-complexation approach, and ganciclovir was added to rat smooth muscle cells (A10) in culture with the gels. With complexed HSVtk adenovirus, only cells either in contact with the virus-containing gel or within 50 microm were killed. By comparison, at the same adenovirus and ganciclovir dose, non-antibody-complexed HSVtk adenoviral delivery with ganciclovir resulted in the death of virtually all cells. Myocardial gene transfer studies in pigs demonstrated significantly more efficient right ventricular adenoviral GFP expression with anti-hexon antibody-complexed matrix injections, compared with direct vector injections. Thus, our results show that matrix formulations based on antibody-complexation delivery of adenovirus resulted in site-specific localization of transgene expression that enhances the efficiency of therapeutic vector strategies and provides a potent means for localization, to avoid distal side-effects. This approach has therapeutic potential as an implantable preparation that through the means of antibody-complexation, can localize and optimize viral vector gene therapy.