Adenovirus (AdV) is a member of the family Adenoviridae, whose name derives from their initial isolation from human adenoids in 1953 . It is a medium-sized (90-100nm) and non-enveloped virus with an icosahedral nucleocapsid containing a double-stranded DNA genome. With a broad range of vertebrate hosts, 100 serotypes have been isolated, and about 57 distinct adenoviral serotypes in humans, causing a wide range of diseases, from mild respiratory infections in young children to life-threatening multi-organ disease in people with a weakened immune system. Since the isolation of adenoviruses, they were recognized as an invaluable tool for investigating mammalian molecular biology [2-4]. Considering the pathogenicity, recombinant adenovirus (rAdV), a replication-defective adenoviral vector system, is widely used for gene delivery in most cell types.
Based on human adenovirus type 5 (Ad5), recombinant adenovirus is replication-incompetent (-E1/-E3) and can’t be integrated into host genome, guaranteeing the security for subsequent operations . With large cargo capacity (~8kb), and they are easily manipulated with recombinant DNA techniques. What’s more, recombinant adenovirus can efficiently transduce dividing and non-dividing cells and can be produced with high titers. All of these distinguishing features make adenovirus a preferred vehicle for gene delivery and transgene expression in mammalian cells .