A hexon-specific PEGylated adenovirus vector utilizing blood coagulation factor X.
We previously developed a hexon-specific PEGylated adenovirus (Ad) vector by utilizing avidin-biotin interaction.  However, the Ad vector was aggregated due to the multiple interactions between avidin and biotin, resulting in a reduction in the transduction efficiencies in the organs following systemic administration.  In this study, we developed a new method for hexon-specific PEGylation by mixing Ad vectors with PEGylated blood coagulation factor X (FX) (PEG-FX).  FX specifically binds to the hexon protein, suggesting that FX serves as an adaptor molecule for hexon-specific modification.  Intravenous administration of the PEG-FX-associated Ad (PEG-FX-Ad) vector into conventional mice resulted in prolonged blood retention.  However, the transduction efficiencies in the liver were not reduced by PEG-FX.  On the other hand, in the warfarinized mice, the PEG-FX-Ad vectors exhibited a significant reduction in the liver transduction.  In addition, incubation of the PEG-FX-Ad vector with unmodified FX resulted in dissociation of PEG-FX from the Ad vector, indicating that a substitution of PEG-FX with endogenous FX occurs in the blood following administration.  This study demonstrates that FX can be used as an adaptor molecule for hexon-specific modification; however, modified FX might be substituted with endogenous FX in the blood.