Technology
The proprietary TESSA® (Tetracycline enabled self-silencing adenovirus) technology delivers high titer and high quality AAV to gene therapy pioneers. Our team engineers TESSA® vectors to encode your gene or capsid of interest for high quality manufacture of AAV. The result is an easily scalable, contaminant-, chemical- and transfection- free technology.
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Overcome typical challenges in scale and costs to meet market demand.
Combining upstream yield and % full increases overall yield by 10x.
Reduced HCD levels in AAV particles.
No TESSA® contamination in AAV production.
Drastic reduction in material costs plus process improvement gains.
Infection based process to scale at 2000L or greater.
Leverage integrated development, manufacturing, and testing to streamline timelines.
Anyone who needs to produce a large amount of AAV to adequately meet patient demands or are targeting indications that require high doses of AAV can gain from the application of TESSA® technology. In addition, developers who are facing challenges related to the cost of production or struggling to meet quality or yield targets may also want to evaluate TESSA®.
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TESSA® vectors take advantage of the adenoviral lifecycle, which contains two temporal phases: early and late. The early phase provides all the adenoviral help needed for high fidelity, high titer AAV manufacture. The late phase leads to adenovirus contamination.
We’ve engineered supremely tight regulation of the adenoviral late region, which is wholly responsible for producing adenovirus structural proteins. Using TESSA® technology, full early region expression, which provides all the help needed for AAV production, is enabled. However, the late region gene expression is turned off, meaning there is no adenoviral structural protein production.
This tightly represses adenovirus production during an AAV manufacturing run, while increasing recombinant AAV (AAV) yield, packaging efficiency and infectivity compared to both Ad5 helper plasmid or wild-type adenovirus. Stable integration of AAV Rep and AAV Cap into the TESSA® vector allows efficient and simultaneous delivery of all the necessary components for AAV replication in a single agent.
TESSA® vectors can be combined in two different ways to produce AAV. The process variation between the two approaches is the method by which the gene of interest (GOI) is introduced. A TESSA® vector encoding Rep and Cap can be combined with either a TESSA® vector (TESSA® Duo model) or an AAV encoding the GOI (TESSA® Pro model.)
We observe an increase in AAV2 infectious yield where 1 in 23 genomes containing AAV2 particles is infectious from TESSA® , compared to 1 in 186 from plasmid-based system. Producing AAV2 using TESSA® Duo (two TESSA® vectors) results in ~43-fold total increase in AAV particle yields compared to the 3-plasmid system. The full power of TESSA® is realized through the combination of the percentage full improvement (left) with the upstream yield improvement. For AAV6-EGFP & AAV2-EGFP, this has meant a 31.4-fold & 42.9-fold higher yield than that achieved using the 3-plasmid system. We also see an increased percentage of full capsids from 73% up to 95%.
A Tet repressor (TetR) binding site is inserted into the Major late promoter, while the TetR gene itself is encoded within the late region. This creates a negative feedback loop, where adenoviral structural proteins can only be produced in the presence of doxycycline.
Using two TESSA® vectors (Duo) to produce AAV6 in a 50L bioreactor results in a 10-fold improvement in the AAV6 yield compared the 3-plasmid system. Consistent AAV2 yields across a range of production scales (125mL-200L) demonstrate the scalability of manufacturing using TESSA®.
Top: The gene of interest (GOI) is packaged more efficiently into AAV made using TESSA® Duo and this results in a higher percentage of particles containing the full sequence of the GOI (full particles). AAV6- EGFP produced using TESSA® Duo at 200L scale had 26% more full particles than those produced using the 3- plasmid system.
Bottom left: This higher percentage of full particles appear lighter when negative stained and visualized using electron microscopy. Bottom right: This higher percentage full particles is enriched in the post drug substance, which contains 94.4% full particles. Scale bar = 200nm.
AAV2 produced using TESSA® Duo (blue) contains significantly more infectious particles (1 in 23) than those made using the 3-plasmid system (1 in 186) (grey). As seen on the right, a higher number of infectious particles translates to greater transduction efficiency, as demonstrated by the relative expression levels of EGFP in HEK293 & U87 cell lines.
Large scale manufacturing of AAV using TESSA® technology eliminates the need for costly starting materials. It’s ideally suited for rapid and robust production of GMP quality AAV, using the same batch of TESSA® starting material for multiple runs reduces the potential for batch-to-batch variation. Ultimately, TESSA® technology will result in economic benefits whilst improving the safety of AAV gene therapies.
OXGENE, a WuXi Advanced Therapies Company, offers an in-house evaluation service for TESSA® Duo and Pro. We design and construct a custom TESSA® -GOI vector and conduct a head-to-head comparison of AAV manufacture and transient transfection. We start in shake-flasks and then scale up to a 1L or 10L bioreactor. You’ll receive the resulting AAV and data-pack containing all the analytics.
OXGENE, a WuXi Advanced Therapies Company, offers an in-house evaluation service for TESSA® Duo and Pro. We design and construct a custom TESSA® -GOI vector and conduct a head-to-head comparison of AAV manufacture and transient transfection. We start in shake-flasks and then scale up to a 1L or 10L bioreactor. You’ll receive the resulting AAV and data-pack containing all the analytics.
Each pack contains everything needed for your own studies: AAV-EGFP and RepCapX vectors as well as the validated WuXi Advanced Therapies cell line. Two pack sizes are available for the production of approximately 1L and 10L of AAV.
Our team can supply custom research grade of TESSA® vectors or GMP production of TESSA® vectors or event AAV using TESSA® vectors. You can also purchase off the shelf GMP grade TESSA® vectors.
We have fully qualified analytical assays for both characterization and release of AAV manufactured using TESSA® ready for GMP manufacture at WuXi Advanced Therapies.
An evaluation project will typically take anywhere from 3 to 6 months from start to finish.
We will host a kick-off call to answer any questions you may have before you start your evaluation. During that call we will also agree how often to meet during your self-paced evaluation.
Our stocks are currently frozen for over a year and are still viable, have good stability, and are stored in aliquots that can infect a 200L production-scale bioreactor. Stability could be measured in 2 ways. Firstly, the physical stability of the Ad vectors during storage at -80°C, and secondly, genetic stability following multiple rounds (passages) of serial re-amplification. TESSA Ad vectors are likely to be just as stable as other Ad5 vectors which can be stored at -80 degrees C for many years. We have tested the genetic stability of the TESSA-RepCap vectors at up to 10 serial passages and observed no changes. Here we test to ensure that the AAV rep and cap genes and the Ad Hexon gene are all still present.
Cheaper at both 1L and 10L scale. With TESSA® Pro at 1L scale, we can generate AAVs equivalent to a 10L production run using the plasmid system.
AAV-2 because the ITR’s most commonly used in AAV drug candidates are from AAV-2.
We can engineer your custom capsid in the TESSA® vector to be used in TESSA® Duo or Pro process. The yield may vary.
Please contact us and we can schedule a time for you to meet with our scientists. Once we have a CDA in place, we can share a great deal more information about the technology, timelines, commercial arrangements and more.