Achieving High-Yield Production of Functional AAV5 Gene Delivery Vectors via Fedbatch in an Insect Cell-One Baculovirus System

Abstract

Despite numerous advancements in production protocols, manufacturing AAV to meet exceptionally high demand (1016–1017 viral genomes [VGs]) in late clinical stages and for eventual systemic delivery poses significant challenges. Here, we report an efficient, simple, scalable, robust AAV5 production process utilizing the most recent modification of the OneBac platform. An increase in volumetric yield of genomic particles by ∼6-fold and functional particles by ∼20-fold was achieved by operating a high-cell-density process in shake flasks and bioreactors that involves an Sf9-based rep/cap stable cell line grown at a density of about 10 million cells/mL infected with a single baculovirus. The overall volumetric yields of genomic (VG) and bioactive particles (enhanced transducing units [ETUs]) in representative fedbatch bioreactor runs ranged from 2.5 to 3.5 × 1014 VG/L and from 1 to 2 × 1011 ETU/L. Analytical ultracentrifugation analyses of affinity-purified AAV vector samples from side-by-side batch and fedbatch production runs showed vector preparations with a full and empty particle distribution of 20%–30% genomic and 70%–80% empty particles. Moreover, the stoichiometric analysis of capsid proteins from fedbatch production in shake flask and bioreactor run samples demonstrated the incorporation of higher VP1 subunits, resulting in better functionality.