What is the Difference Between Adeno-associated Viral Vector and Adenoviral Vector?

The main difference between adeno-associated viral vectors (AAV) and adenoviral vectors (AVV) lies in their genetic makeup. AAV is composed of a single-stranded DNA viral vector, while adenoviral vectors consist of double-stranded DNA. Both are used as viral vectors for gene delivery and have the ability to infect a broad range of hosts, including dividing and non-dividing cells, without integrating with the host genome. However, there are several key distinctions between them:

1. Packaging Capacity: Adenoviruses have a capacity of ~8.5 kilobases, while AAVs have a packaging capacity of ~4.5 kilobases.
2. Level of Protein Expression: Adenoviruses have high levels of protein expression, whereas AAVs have relatively low levels of protein expression.
3. Onset and Duration of Gene Expression: The onset of expression for adenoviruses can occur as early as 16-24 hours after infection, with transient gene expression. AAVs, on the other hand, have the potential for long-lasting gene expression.
4. Immune Response: Adenoviruses elicit a high immune response from target cells, which is the main limitation of adenoviral systems. AAVs do not cause significant immune responses.

Both adenovirus and AAV serve as essential viral vectors for delivering therapeutic genes to target cells, making them fundamental tools in gene therapy. Researchers can modify these vectors by engineering them to transport certain genes or gene-editing tools, leading to precise genetic modifications.

Comparative Table: Adeno-associated Viral Vector vs Adenoviral Vector

Here is a table comparing adeno-associated viral vectors (AAV) and adenoviral vectors (AVV):

AAV is a single-stranded DNA viral vector with a small foreign DNA capacity, while AVV is a double-stranded DNA viral vector with a larger foreign DNA capacity. AAV does not integrate into the host genome and is known for its long-term expression, whereas AVV can integrate into the host genome and typically provides short-term expression. AAV has been shown to be safe and effective in preclinical and clinical settings, while adenoviral vectors have been associated with inflammation and toxicity.