Anti-AAV5 (aa 530-541) polyclonal antibody

Adeno-associated virus (AAV) was originally identified in adenovirus isolates grown in the lab and soon afterwards in human tissues. AAV would not have successful infection or replication without helper viruses, like adenovirus or herpes simplex virus. Without a helper virus, AAV could become site-specifically incorporated into the host genome or it could stay stuck as an episome, incubating latent infection in the cell. Due to its safety profile, AAV has become an important vector platform for in vivo gene therapy. In contrast to other viral vectors, AAV causes no human disease, is very low in immunogenicity, only expresses episomally, and has a very low integration frequency. AAV is one of the most promising and used gene-transfer devices today.

Figure 1. Schematic representation of the basic components of a gene insert packaged inside recombinant AAV gene transfer vector
(Source: Naso MF, et al. 2017)

AAV is not enveloped, and has an icosahedron with diameter between 20 and 26 nm. Inside the virus, there's a 4.7 kb single-stranded DNA genome made of two giant ORFs, Rep and Cap. Rep code for four proteins that enable viral replication and assembly, and Cap codes for the structural proteins VP1, VP2, and VP3 and the assembly-activating protein (AAP). VP1, VP2, and VP3 together form the icosahedral particle of the virus, with VP1 and VP2 sharing the sequence of VP3 and having additional residues at their N-terminus. AAP is crucial for capsid assembly and is encoded by an in-frame overlapping ORF within the Cap gene. There are only two cis-acting repeats – the inverted terminal repeats (ITRs) – on either side of the AAV genome for genome replication and packing.

More than 100 AAV serotypes and variants have been identified, including 12 primate serotypes known as AAV1 through AAV12. AAV serotypes 1 to 6, except for AAV5, were discovered during laboratory adenovirus preparations. AAV5 was isolated from human tissues. The differences between various AAV serotypes mainly lie in the variations of their capsid protein, Cap. Due to the diversity of AAV serotypes, they can infect different types of cells by targeting different cell surface receptors, exhibiting varying tissue tropisms. Among them, AAV5 has a higher transduction efficiency for sensory neurons. With the rapid development of AAV vectors, researchers have conducted extensive genetic modifications on the AAV capsid, resulting in numerous variants with modified characteristics. This has made AAV a versatile vector for gene therapy applications in various genetic diseases.

Anti-Adeno-associated virus 5 (aa 530-541) polyclonal antibody