Development of fiber-substituted adenovirus vectors containing foreign peptides in the adenovirus serotype 35 fiber knob

Abstract

Fiber-substituted adenovirus (Ad) vectors containing fibers of Ad serotype 35 (AdF35) efficiently transduce a variety of human cells because their receptor, human CD46, is ubiquitously expressed on almost all nucleated cells. However, the ubiquitous expression of CD46 might lead to unexpected transduction in untargeted organs. In this study, we developed fiber-modified AdF35 vectors with an integrinbinding Arg-Gly-Asn (RGD) peptide incorporated into the FG, HI or IJ loop, which have been identified as important regions for binding to CD46. Incorporation of foreign peptides into these loops does not inhibit trimerization of the fibers. In CD46-negative cells, fiber-mutant AdF35 vectors containing an RGD peptide in the FG or HI loop showed 6-to 30-fold higher transduction efficiencies in an RGD-peptide-dependent manner than the unmodified AdF35 vectors. In contrast, in CD46-positive cells, insertion of foreign peptides markedly reduced the transduction efficiencies of the AdF35 vectors, indicating that insertion of foreign peptides significantly inhibits binding to CD46. In particular, CD46-mediated transduction was completely diminished by insertion of foreign peptides into the HI loop. Our findings indicate that HI loop is the most suitable domain to mediate a foreign peptide-dependent and CD46-independent transduction by incorporation of foreign peptides into the Ad35 fiber knob.

Protection against Enterovirus 71 with Neutralizing Epitope Incorporation within Adenovirus Type 3 Hexon

“…Recently a novel approach is developed to incorporate antigenic epitopes into the Ad capsid proteins: hexon, fiber knob, and penton base, as well as protein IX [19], [20], [21], [22]. Incorporating immunogenic peptides into the Ad capsid offers potential advantages: a strong humoral response similar to the response generated by native Ad capsid proteins, allowing boosting of the immune response against antigenic epitopes that are part of the Ad capsid [18].…”

Retargeting Adenovirus Serotype 48 Fiber Knob Domain by Peptide Incorporation

“…Hesse and colleagues highlighted the suitability of the EG, HI, and IJ loops within the short fiber of species F adenovirus, Ad41, for the insertion of an integrin targeting Arg-Gly-Asn (RGD) motif (Hesse et al, 2007). The FG and HI loops of species B adenovirus, Ad35, also have been shown to tolerate the insertion of RGD-containing peptides (Matsui et al, 2009). Both retargeting approaches resulted in improved am-integrin-mediated transduction efficiency in vitro.…”

“…Attempts previously have been made to genetically modify the fiber of species B (Ad35) (Matsui et al, 2009), D (Ad19p fiber) (Denby et al, 2007), and F (Ad41 short fiber) serotypes (Hesse et al, 2007). The insertion of peptides within the EG, HI, and IJ loops of these fiber knobs was found to be compatible with fiber trimerization and resulted in successful modification of tropism (Denby et al, 2007;Hesse et al, 2007).…”

Enhanced in vivo gene transfer into the placenta using RGD fiber-mutant adenovirus vector

“…Also, our observations collectively have important implications for strategies that could be applied to potential gene therapy, for example for placental insufficiency. Recent progress in the development of Ad vectors has provided a way to suppress Ad-mediated gene expression in the liver by utilizing tissue-specific miRNAs such as miR-122a or fibersubstituted chimeric Ad containing the fiber of Ad serotype 35 (AdF35), into which foreign peptides can be inserted [6,51]. The miRNA-based modification of Ad was simple and effective in controlling transgene expression in some tissues.…”