High-throughput, automated analysis of viral vector titer and process-related impurities
Adeno-associated virus (AAV) based vectors have become the go-to vehicle for systemic delivery of gene therapies. Vector production is, however, an expensive and complex process that results in a small volume of highly valuable product yet sample analysis during bioprocess steps can consume up to one half of a production batch. Analysis can also require extensive laboratory resources, especially where traditional immunoassays such as plate-based ELISAs are employed.
To explore a solution to these challenges, we investigated analyzing viral vector titer and impurities in a continuous 5-CD run using the Gyrolab® xPand platform and a combination of Gyrolab kits and assay protocols. Two AAV serotypes (AAV2 and AAV9) plus 3 impurities (host-cell proteins [HCPs], endonuclease, and transferrin) were analyzed for each serotype on one instrument.
The ability to automate and miniaturize five unique immunoassays for two AAV serotypes on one instrument in one run of under 6 hours represents significant hands-on time and sample volume savings compared to manual ELISA or other plate-based methods.
Key features include:
- Titer for two AAV serotypes (AAV2 and AAV9) plus 3 impurities (host-cell proteins [HCPs], endonuclease, and transferrin) were analyzed for each serotype in one run in under 6 hours, saving considerable hands-on time over plate-based methods.
- The total volume of neat sample consumed for the complete set of four assays per AAV serotype was approximately 40 μL, representing very low sample volume requirements for the assays.
- Kits used in the analysis were: the AAVX Titer Kit, AAV9 Titer Kit, HEK 293 HCP Solution for Gyrolab, EndonucleaseGTP Solution for Gyrolab, and Gyrolab assay protocol for transferrin, providing convenience and reliable assay performance.
- The samples all demonstrated dilutional linearity and low CVs (almost all under 10%), confirming the robustness of the assays.
- Overall, the 5-CD run time was less than 6 hours on the Gyrolab xPand system, with all assays fully automated after a hands-on time of approximately 1 hour to set up microplates with standard curves and samples for the 5 assays.