Antibody purification has been well studied and platform technologies have been created that purify multiple antibody products on similar purification trains. On the contrary, non-antibody therapeutics such as vaccines face a challenge in adopting conventional unit operations steps that can efficiently purify large viral particles. Some major issues that plague vaccine purification are purity, potency and quality. For example, the biopharmaceutical industry currently considers 30% an acceptable virus recovery. For antibodies, the acceptable recovery is generally around 80-85%. A platform technology would revolutionize vaccine production. The goal would be to produce a higher yield with alternative unit operations. In a quest to fulfill this goal, we have been exploring aqueous two phase systems (ATPS) as an optional mechanism to purify virus. ATPS has been unable to gain wide implementation mainly due to loss of virus infectivity, co-purification of proteins, and difficulty of polymer recycling. Loss of immunogenic property is likely due to the unfolding of the virus structure. Compared to enveloped viruses which have a sensitive bilayer, the majority of non-enveloped virus families Reovirus, Picornavirus, Polyomavirus and Parvovirus are known to withstand phase separations with polyethylene glycol. We use infectious porcine parvovirus (PPV), a non-enveloped DNA virus of 18-26 nm diameter, as a model virus to test and develop an ATPS separation method. We successfully achieved an infectious yield of 57% in a PEG-citrate ATPS. We completely eliminated the major contaminant protein, bovine serum albumin (BSA), from host cell media. We are currently determining a method to recover the virus from the PEG, creating a virus purification system. Once an ATPS method is created for PPV, it will be applied to other non-enveloped viruses to explore the option of a platform purification approach for vaccines.

Purification of a non-enveloped virus using aqueous two phase system

247th National Meeting (2014)

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