AAV Manufacturing
With several AAV-based gene therapies now approved and many more in clinical development, scalable and high-quality AAV manufacturing has become a critical component of therapeutic success.
AAV Manufacturing Platforms
AAV manufacturing platforms provide the technological foundation for producing recombinant AAV vectors used in gene therapy research, preclinical studies, and clinical applications. These platforms differ in vector yield, product quality, scalability, cost, and regulatory readiness, and have evolved significantly to address the growing demands of in vivo gene delivery.
Early AAV production relied primarily on transient transfection–based systems, which remain widely used due to their flexibility and ease of implementation. However, challenges such as limited packaging efficiency, batch-to-batch variability, high plasmid requirements, and manufacturing cost. Modern AAV manufacturing strategies aim to achieve higher productivity, improved full-to-empty capsid ratios, reduced impurities, enhanced reproducibility, and lower cost, while maintaining compatibility with scalable suspension culture and regulatory expectations. Selecting an appropriate AAV manufacturing platform is therefore a critical decision that directly impacts vector quality, development timelines, and clinical translation.
- Transient Transfection/HEK293 Platform: The most widely used method for AAV production, such as AAVone® and AAVtri.
- Stable Producer Cell Line Platform: Cells are engineered to stably express one or more AAV components
- Baculovirus/Sf9 Insect Cell Platform: Uses baculovirus expression vectors in Spodoptera frugiperda (Sf9) insect cells to produce AAV in suspension.
- Other Platforms: such as TESSA, HSV/BHK, VV-Ad system.
Transient Transfection/HEK293 Platform
The Transient Transfection platform using HEK293 cells is the most widely used method for AAV vector production, especially in early-stage research, preclinical studies, and clinical manufacturing. This flexible and robust system allows rapid generation of AAV vectors by introducing plasmid DNA into mammalian cells that are capable of producing high AAV yields.
Key Components:
Plasmids: Typically a triple plasmid system [Xiao et al., 1998]
Cell Line: HEK293 or derivatives (e.g., HEK293T, HEK293F, HEK293FT, HEK293one)
Transfection Reagent: PEI, PEImax, PEIpro, PEIone, or commercial alternatives
The most common method of AAV manufacturing involves triple-plasmid transient transfection (AAVtri) of HEK293 cells. This method requires the co-transfection of three plasmids:
- pAAVtri: Contains two inverted terminal repeats (ITRs), the only cis-element necessary for AAV replication and packaging. The transgene cassette is placed between these two ITRs.
- pRCap: Provides AAV helper functions, including encoding the necessary Rep proteins (Rep78, Rep68, Rep52, Rep40). Only Rep78 and Rep52 are essential as trans elements for AAV production. The capsid proteins (VP1, VP2, VP3) are also required for capsid assembly.
- pHelper: Supplies adenovirus (Ad) helper functions, such as E2A, E4orf6, and VA RNA, to enhance AAV production. Recently, the adenoviral 22K and 33K proteins have also been reported to be involved in AAV packaging within the AAVtri system [Adsero et al., 2024] .
Although the AAVtri system has proven to be safe, convenient, and effective in clinical trials, it faces challenges with traditional AAV manufacturing, especially scalability limitations. Transfecting all three plasmids simultaneously can:
Requires co-transfection of three plasmids into the same cell, limiting packaging efficiency
Competition for cellular resources reduces overall AAV production efficiency
Batch-to-batch variability due to plasmid quality fluctuations; precise plasmid ratio optimization is required
GMP-grade plasmid production (>95% purity) is time-consuming and costly
High DNA input required (typically ~1 µg plasmid per 1 × 10⁶ cells)
Higher impurity risk in final vectors, particularly from plasmid backbone sequences
AAVnerGene's Solution for AAV Manufacturing
AAVnerGene has developed a suite of innovative technologies to enhance AAV productivity and significantly reduce AAV manufacturing costs. By integrating these advancements—including optimized cell lines, proprietary plasmid systems, and high-efficiency transfection reagents—we are able to consistently achieve AAV9 titers exceeding 5 × 10¹² VG/mL in crude harvests. This level of productivity positions AAVnerGene as an industry leader in scalable and cost-effective AAV manufacturing.
Plasmid Design: AAVone, AAVdual and AAVtri
- AAVone® (single-plasmid) system, capable of achieving AAV9 productivity exceeding 5e15 vg/L in HEK 293one cells with full particle ratio over 70%.
- AAVdual® (two-plasmid) system, designed to balance productivity with flexibility.
- AAVtri, the smaller mini-pHelper-1.0 plasmid (8.4kb) offers higher packaging efficiency.
AAVone® system is designed to streamline AAV production process, increase AAV yield, improve product consistency and reduce the cost and labor, especially for GMP grade AAV production. In the AAVone system, all the Ad helper genes (E2A, E4orf6 and VA RNA), AAV helper genes (Rep and Cap), and AAV vector genome are assembled into one plasmid and AAV vectors are simply generated by transfection one plasmid into host cells. AAVone has demonstrated impressive productivity, which is 2~4 fold higher than original triple plasmid transfection system.
We recently developed the second-generation AAVone system (AAVone2.1), which significantly improves the full-to-empty capsid ratio. For most AAV serotypes, AAVone2.1 achieves approximately 70% full particles in both our HEK293one cell line and VPC2.0 cells.
Fully adapted to FreeStyle F17/Viral Production Medium, PEAK/PRIME, and Pro293 media
High AAV productivity across multiple production platforms and compatibility with various AAV serotypes
High full-to-empty ratio across multiple serotypes
Scalable for large-volume AAV production
Compatible with multiple transfection reagents, especially our PEIone transfection reagent
Available for research use under license, cGMP cell banks are currently in preparation
High DNA-binding capacity with our pAAVone plasmids (it also works with traditional triple-plasmid transfection method)
Low transfection complex ratio, reducing reagent waste
Exceptional complex stability, ensuring consistent transfection efficiency
References:
- Production of high-titer recombinant adeno-associated virus vectors in the absence of helper adenovirus. J Virol. 1998 Mar;72(3):2224-32. doi: 10.1128/JVI.72.3.2224-2232.1998.
- Adsero A, Chestnut B, Shahnejat-Bushehri S, Sasnoor L, McMurphy T, Swenor M, Pasquino R, Pradhan A, Hernandez V, Padegimas L, Dismuke D. A Novel Role for the Adenovirus L4 Region 22K and 33K Proteins in Adeno-Associated Virus Production. Hum Gene Ther. 2024 Jan;35(1-2):59-69. doi: 10.1089/hum.2023.146.
- Rongze Yang et al., AAVone: A Cost-Effective, Single-Plasmid Solution for Efficient AAV Production with Reduced DNA Impurities. https://www.sciencedirect.com/science/article/pii/S2162253125001179