Is AAV a viral vector?
One limitation of AAV vectors is their small packaging size (~5.0 kb, including ITRs) compared with other viral vectors. However, several strategies have been investigated to enable delivery of a large therapeutic gene.
How does AAV infect cells?
When AAV infects a cell alone, its gene expression is repressed (AAV does not replicate), and its genome is incorporated into the host genome (into human chromosome 19). In rare cases, lysis can occur without a helper virus, but usually AAV can not replicate and kill a cell on its own.
How does an AAV vector work?
How does AAV work? Simply put, AAV is transformed from a naturally occurring virus into a delivery mechanism for gene therapy. The viral DNA is replaced with new DNA, and it becomes a precisely coded vector and is no longer considered a virus, as most of the viral components have been replaced.
What is the difference between AAV and adenovirus?
Adenoviruses have a capacity of ~8.5 kilobases, high levels of protein expression, and transient gene expression….Adenovirus vs. AAV.
| Adenovirus | AAV | |
|---|---|---|
| Protein Expression | High | Low |
| Gene Expression | Transient | Potentially Long Lasting |
| Target Cell’s Immune Response | High | Very Low |
What is a viral vector platform?
Viral vector-based vaccines differ from most conventional vaccines in that they don’t actually contain antigens, but rather use the body’s own cells to produce them.
Is AAV a satellite virus?
Indeed, as it came to be known, in addition to the unavoidable host cell, AAV typically needs a so-called helper virus such as adenovirus to replicate. Since the AAV life cycle revolves around another unrelated virus it was dubbed a satellite virus.
Is AAV a retrovirus?
Overall, AAV can be produced at a moderately high titer and can infect target cells efficiently, but less so than adenovirus. Retrovirus (e.g. MMLV) can introduce genetic material into the genome of the host cell, making it great for long-term stable expression.
How are viral vectors produced?
“There are three basic ways to produce viral vectors: using a stable packaging cell line, using transient transfection, or using infection,” Dr. van der Loo explains.
How is AAV packaged?
AAV genomes flanked by inverted terminal repeats are packaged as ssDNA into empty preformed capsids. The packaging mechanism couples the replication and encapsidation process. The small Rep proteins play a central role in the translocation of the genome into the capsid.