Development of a scalable production bioprocess for HIV-1 virus-like particles coupling continuous VLP harvesting with end-to-end downstream processing.

HIV-1 Gag virus-like particles (VLPs) have been drawing attention as vaccine platform for their non-infectivity, ability to induce robust immune responses and versatility. However, challenges in their production, purification, and preservation still hinder their application. The production process, often reliant on transient gene expression (TGE), faces scalability limitations. Moreover, the downstream processing (DSP) presents challenges, including separating VLPs from extracellular vesicles (EVs), scale-up, and the lack of analytical methods to monitor the entire process. A complete bioprocess for Gag VLPs production is presented here, combining perfusion-based upstream production with a three-step DSP. Perfusion-based continuous production of Gag VLPs demonstrated significant yield improvements, with a 2.4-fold increase in VLP volumetric productivity compared to previous methods. Subsequent DSP steps, including secondary clarification and anion exchange chromatography (AEC) capture, resulted in approximately 60% recovery and purity. This ensures its scalability potential and robustness. The post-purification lyophilization step maintained VLP integrity and stability. This study presents an intensification strategy to address critical challenges in Gag VLP production, purification, and preservation, offering insights into enhancing vaccine biomanufacturing and distribution.