Replacement of Native Adenovirus Receptor-Binding Sites with a New Attachment Moiety Diminishes Hepatic Tropism and Enhances Bioavailability in Mice (original) (raw)

The in vivo efficacy of adenovirus vectors (AdVs) in gene delivery strategies is hampered by the broad tissue tropism of the virus and its efficient binding to human erythrocytes. To circumvent these limitations, we developed a genetically targeted prototype AdV. We replaced the adenovirus fiber with a chimeric molecule consisting of the fiber tail domain, the reovirus σ1 oligomerization domain, and a polyhistidine tag as model targeting moiety. We also abolished the integrin-binding motif in the penton base protein. The chimeric attachment molecule was efficiently incorporated onto AdV capsids, allowed efficient propagation of AdV without requirement for complementing fiber and conferred highly specific tropism to the AdV. Importantly, the targeted AdV exhibited markedly reduced tropism for liver cells. In comparison to control AdV with native tropism, the targeted AdV showed 1,000-fold reduced transduction of HepG2 cells and 10,000-fold reduced transduction of mouse liver cells in freshly isolated liver slices. Following intravenous inoculation of C57BL/6 mice, the targeted AdV exhibited delayed clearance in comparison to the native AdV, leaving approximately 10-fold greater levels in the blood 2 h after inoculation. For all tissues analyzed, the targeted AdV displayed significantly reduced in vivo transduction in comparison to the native vector. Furthermore, in contrast to the native AdV, the targeted AdV did not bind human erythrocytes. Together, our findings suggest that the targeted AdV design described here provides a promising platform for systemic in vivo gene delivery.