An integrated and continuous downstream process for microbial virus-like particle vaccine biomanufacture

In this study, we present the first integrated and continuous downstream process for the production of microbial virus-like particle vaccines. Modular murine polyomavirus major capsid VP1 with integrated J8 antigen was used as a model virus-like particle vaccine. The integrated continuous downstream process starts with crude cell lysate and consists of a flow-through chromatography step followed by periodic counter-current chromatography (PCC) (bind-elute) using salt-tolerant mixed-mode resin and subsequent in-line assembly. The automated process showed a robust behavior over different inlet feed concentrations ranging from 1.0 to 3.2 mg ml^-1 with only minimal adjustments needed, and produced continuously high-quality virus-like particles, free of nucleic acids, with constant purity over extended periods of time. The average size remained constant between 44.8 ± 2.3 and 47.2 ± 2.9 nm comparable to literature. The process had an overall product recovery of 88.6% and a process productivity up to 2.56 mg h^-1 ml_resin^-1 in the PCC step, depending on the inlet concentration. Integrating a flow through step with a subsequent PCC step allowed streamlined processing, showing a possible continuous pathway for a wide range of products of interest.