AAV production services: specifying custom aav production, aav packaging services, aav services generally and any aav service by titre, purity and the aav empty capsids fraction that decides the dose

Specifying the preparation

1. Serotype and the packaging limit. Serotype determines tropism and is chosen from the target tissue and route. The packaging capacity is a hard limit on the genome, and a construct over it produces truncated genomes rather than a warning, so confirm the total size including the inverted terminal repeats and regulatory elements early.
2. Titre is method dependent. Genome-containing particles measured by amplification, total capsids measured immunologically and infectious units measured in cells are three different numbers. Ask which method is used, on which standard, and prefer providers who report more than one so the preparation can be understood.
3. Empty and full capsid ratio. Empty capsids carry no genome, contribute to the immune load and dilute the effective dose. The full to empty ratio should be measured and reported per lot, and a preparation with a poor ratio needs a higher total dose to achieve the same delivery.
4. Purification route. Density gradient separation enriches full capsids and is slower; chromatography scales better and varies in how well it separates empties. Ask which route is used and what ratio it achieves, since this is the largest quality difference between providers.
5. Residuals and endotoxin. Residual host cell protein and DNA, residual plasmid and helper sequences, and endotoxin should all have stated limits and lot results, particularly for in vivo work where they drive the response as much as the vector does.

Research grade against material for regulated use

Research grade preparations are made without a quality system and cannot be used to support a regulated application later. If a programme may move that way, ask now what would change and at what cost, because the process, the documentation and the testing all differ.

Plasmid quality feeds directly into vector quality, so where the programme is heading toward regulated use the plasmids need attention at the same time as the vector.

Testing what arrives

Verify titre in your own hands where you can, and always test a small aliquot for function before committing an experiment or an animal cohort. Provider titres are measured by the provider's method against the provider's standard.

Keep a retained aliquot of every lot. A change in results between lots cannot be investigated without one, and vector lots vary more than most reagents.

Common questions

Why does the empty capsid ratio matter?

Empty capsids carry no genome, so they dilute the effective dose and add to the immune load without delivering anything. The full to empty ratio should be measured and reported for every lot.

Which titre method should I ask for?

Ask which is used, because genome-containing particles, total capsids and infectious units are three different numbers. Providers reporting more than one give you a preparation you can actually understand.

What limits my construct size?

The packaging capacity of the capsid, counting the whole genome including the inverted terminal repeats and regulatory elements. Exceeding it produces truncated genomes rather than an error, so confirm the total early.

Can research grade AAV support a regulated application later?

No. Material for regulated use needs a different process, documentation and testing package, and it cannot be applied retrospectively. Ask what would change before the programme commits.

Browse by service class

• Compare Gene synthesis on advertised prices