Adenoviral Serotype 5 Vectors Pseudotyped with Fibers from Subgroup D Show Modified TropismIn VitroandIn Vivo

Abstract

Adenovirus (Ad5) serotype 5 vectors are commonly used for gene transfer. Preclinical studies have shown that their application to systemic gene delivery, however, is limited by their highly efficient uptake in the liver, principally mediated by receptor-binding sites on the fiber shaft and knob domain. Using Ad to target other sites in vivo requires vectors that lack hepatic tropism. We therefore sought to exploit Ad family diversity to isolate vectors that possessed poor hepatic tropism. We pseudotyped the fibers from Ad16 (subgroup B; Ad5/16), Ad19p (subgroup D; Ad5/19p), and Ad37 (subgroup D; Ad5/37) onto Ad5 capsids and assessed infectivity profiles in vitro in multiple cell types and in vivo in rats. In rat, mouse, and human hepatocytes, Ad5/19p and Ad5/37 both possessed a striking lack of hepatic cell infectivity compared with Ad5. Both vectors were, however, able to transduce human vascular endothelial and smooth muscle cells with efficiencies equal to or greater than that of nonmodified Ad5. We evaluated liver uptake in 12-week-old male rats after intravenous injection. In contrast to a vector with the wild-type Ad5 fiber, Ad5, both Ad5/19p and Ad5/37 produced significantly less virion accumulation (measured at 1 hr and 5 days) and transgene expression in the liver. Thus, Ad5/19p and Ad5/37 may be useful platforms for the development of targeted Ad vectors.

Serotype Chimeric and Fiber-Mutated Adenovirus Ad5/19p-HIT for Targeting Renal Cancer and Untargeting the Liver

“…In accordance with previous work in rats and in a human hepatoma line (Denby et al, 2004), we found significantly reduced liver uptake with Ad5=19p-HIT in comparison with Ad5 (Fig. 5).…”

“…In an earlier study in rats, we found that Ad19p results in less liver transduction than Ad5 (Denby et al, 2004). Ad19p belongs to subgroup D, which contains 32 different serotypes, most of which are rarely isolated from humans (Burmeister et al, 2004).…”

“…Generation and characterization of the replication-deficient adenoviruses used here (Table 1) have been reported (Denby et al, 2004(Denby et al, , 2007.…”

“…Given that Ad5=19p-modified viruses have enhanced tropism to kidney in rats (Denby et al, 2004), we sought to investigate the biodistribution of such vectors after intravenous administration in mice. To this end, five groups of nude mice were injected intravenously with viruses bearing kidneyspecific peptide and compared with Ad5-derived virus.…”

PET imaging of thymidine kinase gene expression in the liver of non-human primates following systemic delivery of an adenoviral vector

“…This can be exploited to target adenoviral-based vectors to this organ, as has been extensively documented in mouse models. 1,2 Adenoviruses provide the basis for various gene therapy vectors and applications in cancer and other diseases. 3,4 Unfortunately, the immune response elicited by the vectors prevents secondary administration thus greatly hampering efficacy.…”