In this age of modern medicine, viral diseases continue to take the lives of millions of people. The most effective method to prevent viral infections is vaccines. However, there needs to be an improvement in current manufacturing virus purification processes to efficiently produce new viral vaccines. In this study, we use virus flocculation in the presence of osmolytes, followed by microfiltration as an alternative purification method to chromatography. Osmolyte flocculants are natural compounds found in cells, with their main functions being to stabilize intracellular proteins and maintain cell volume. They accomplish these functions by preferential interactions with water molecules. We hypothesize that osmolytes are able to specifically flocculate hydrophobic virus particles by depleting the hydration layer around the particles, which leads to virus aggregation. Using high throughput screening, we have discovered a variety of osmolytes, including sugars, sugar alcohols and amino acids, flocculate the non-enveloped porcine parvovirus (PPV) and enveloped Sindbis virus, and demonstrate a &gt;80% removal with a 0.2 μm filter. Removal and purification of a virus with a micropore filter, which is usually used for bacteria removal and not for small viruses, will increase the flux and decrease the transmembrane pressure found in traditional virus filters.<br/><br/>The osmolytes that achieved the highest percent removal were tested for their ability to aggregate and flocculate virus particles at different concentrations, pH, ionic strengths and temperatures, and optimized conditions were determined. We were able to remove both an enveloped and non-enveloped virus with alanine and mannitol, while removal of bovine serum albumin (BSA) and lysozyme was low. Osmolyte flocculation is specific to virus particles, making this a method to purify the virus particles. We propose to use virus flocculation with osmolytes, followed by microfiltration, as a potential platform approach for virus purification that can be applied to many types of viruses with minor modifications per strain. Many of the osmolytes used are known adjuvants for vaccine products, and therefore may not need to be removed from the final product. Osmolyte flocculation is an improvement in viral vaccine purification that could greatly reduce the time to market and cost of development of future vaccine products.

Virus flocculation and recovery with osmolytes

249th National Meeting (2015)

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