Adeno-Associated Virus (AAV)
Adeno-associated virus (AAV) was first identified in 1965 as a contaminant during adenovirus (Ad) preparation, which led to its naming. AAVs are small, non-enveloped viruses (approximately 20nm in size) with a single-stranded DNA genome and belong to the parvovirus family. Given that 80-90% of people are seropositive for AAV2, most individuals treated with AAVs experience no pathogenic effects. Recombinant AAVs (rAAVs) have the capability to infect both dividing and non-dividing cells and can persist in the host cell in an extrachromosomal state, without integrating into the host genome.
Advantages of AAV Compared to Other Viral Vectors:
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Sustained gene expression: rAAV genomes remain in the nucleus as episomes without integrating into the host's genome. Although these episomes may be lost during cell replication, AAV can still enable gene expression for over 6 months in tissues with low rates of cell division.
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High diffusivity: rAAV’s small size and high titer give it superior diffusivity compared to adenovirus and lentivirus, enabling it to cross the blood-brain barrier and making it ideal for targeting neurons and glial cells.
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Targeted expression: AAV can be tailored with a range of promoters and serotypes to specifically target and infect particular organs and cell types, which is why it is frequently chosen for animal research.
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Exceptional safety: AAV has not been linked to any human diseases and is regarded as the safest viral vector, with FDA approval for use in direct gene therapy.
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Minimal immunogenicity: Even when used in high local doses to target tissues such as muscle, brain, or eyes, AAV typically does not provoke a significant immune response.
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Robust stability: rAAV can be stored at 4°C for up to a week and is resistant to certain chemicals, including chloroform.
Virus serotypes
Ignis Bioscience currently provides a range of serotypes, including 1, 2, 5, 6, 8, 9, rh10, DJ, DJ8, PHP.B, PHP.eB, PHP.S, retro, pan, and anc80. Additionally, we can create novel peptide-modified serotypes tailored to specific needs. The choice of serotype determines tissue specificity. If you're unsure which AAV serotype to select, please refer to the following table to find the most suitable option for efficient gene delivery into your target cells or tissues.
How to choose an AAV serotype?
If you're unsure which AAV serotype to select, AAV9 is a good starting point.
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For first-time AAV users: Consider using the Rainbow Colors AAV for preliminary experiments. This allows you to compare the infection efficiency of different serotypes in your target tissue and to optimize factors such as injection method, injection site, and virus dosage for better experimental outcomes.
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Specific applications:
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AAV1: Ideal for anterograde tracing.
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AAV9: Also effective for anterograde tracing.
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AAVRetro: Best suited for retrograde tracing.
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AAV PHP.eB: Designed for crossing the blood-brain barrier.
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Rainbow Colors AAV is a set product that combines common serotypes suitable for different organizations.
Tissue-specific promoters
Ignis Bioscience provides a wide selection of tissue-specific promoters. Below are some of the most frequently selected options. Our promoter database is regularly updated, so if you don’t see the promoter you need, please contact us at support@ignisbio.com.
AAV packaging process
Step 1: Clone the gene of interest into an appropriate viral vector.
Step 2: Co-transfect AAV-293 cells with the recombinant expression plasmid, pHelper (which carries adenovirus-derived genes), and pAAV-RC (which carries AAV replication and capsid genes). These plasmids provide the necessary trans-acting factors for AAV replication and packaging within the AAV-293 cells. Within 2 to 3 days after transfection, recombinant AAV is assembled in the packaging cells.
Step 3: Harvest recombinant AAV viral particles from the transfected AAV-293 cells. These viral particles can then be used to infect various mammalian cells. Since AAV viral particles are typically concentrated within the packaging cells, lysing the cells to release the AAV particles into the supernatant is an effective method for recovering the majority of the viral particles.
Step 4: Concentrate and purify the virus-containing supernatant. The initial supernatant contains numerous intracellular proteins and fragments, so purification is necessary for animal experiments to achieve the required dose and avoid potential side effects.
Step 5: Quantify the AAV vector titer using quantitative PCR (qPCR), a common method to determine the physical titer of the AAV genome packaged within the viral particles. Since infection titer can vary significantly depending on the cell type, AAV coat protein, and test conditions, in vitro experimental data may not accurately reflect in vivo infection rates. Therefore, the physical titer obtained through qPCR provides a more objective measure.
How to Obtain Virus Packaging Services
Ignis Bioscience offers expert, convenient, and research-focused AAV packaging services, from small-scale to large-scale production, to help scientists accelerate their research in circuit tracing, disease mechanisms, and therapeutic development.
We currently have nearly 1,000 pre-made AAV products featuring various serotypes and promoters. Additionally, we have completed over 2,000 customized AAV projects for our clients, utilizing serotypes such as AAV-1, AAV-2, AAV-5, AAV-6, AAV-8, AAV-DJ, AAV-PHP.eB, AAV-retro, AAV-anc80, and AAV-9. We can also produce custom-designed serotypes and vectors tailored to specific needs.
For inquiries or to request services, please contact us at support@ignisbio.com.
Our current pre-made AAVs
Ignis Bioscience provides high-quality, high-titer AAV viral preparation services. Our pre-made AAVs are available in various serotypes, with default titers ranging from 1x10¹² to 1x10¹³ vg/ml. For information on the latest available pre-made AAVs, please contact us at support@ignisbio.com. If you require a higher titer, please explore our Custom-Made AAV Services.