Purification of virus like particles
Methods of purifying virus-like particles (VLPs) that are substantially free of process contaminants and infectious agents. The methods incorporate, for example, low-pH treatment during harvest and/or inactivation by a solvent and/or detergent during VLP capture.
1. A solution comprising a purified population of human norovirus VLPs, wherein the norovirus VLPs comprise at least genogroup II VLPs, wherein said solution contains no more than about 80% residual contaminating protein relative to VLP, and wherein said solution is generated by a process comprising:
generating or obtaining a cell lysate, culture supernatant, or filtrate containing the norovirus VLPs, wherein said norovirus VLPs comprise at least a first subpopulation with full length VP1 subunit and a second subpopulation with truncated VP1 subunit of the norovirus VLPs;
adjusting the pH of the lysate, supernatant or filtrate to a pH of less than about 5 to generate a pH-adjusted solution;
removing the second subpopulation with truncated VP1 subunit of norovirus VLPs from the pH-adjusted solution using a filtration process to generate a filtered solution, wherein the filtered solution substantially retains the first subpopulation with full length VP1 subunit of norovirus VLPs;
and
wherein the solution comprises full length VP1 subunit of norovirus VLPs and is substantially free of norovirus VLPs with the truncated VP1 subunit, wherein the solution contains less than about 10% truncated VP1 subunit.
2. A vaccine comprising the norovirus VLPs prepared from the solution of claim 1 .
3. The solution of claim 1 , containing no more than about 35% residual contaminating nucleic acid relative to the lysate, supernatant or filtrate.
4. The solution of claim 1 , wherein at least about 50% of the norovirus VLPs are recovered from the lysate, supernatant or filtrate.
5. The solution of claim 1 , wherein the ratio of the norovirus VLPs to residual contaminating protein is increased at least about ten-fold as compared to the lysate, supernatant or filtrate.
6. The solution of claim 1 , wherein the solution is suitable for use in a commercial process.
7. The solution of claim 1 , wherein the process further comprises one or more of the following: centrifugation, precipitation, flocculation, settling, and filtration.
8. The solution of claim 6 , wherein the commercial process has a processing volume of at least 20 liters.
9. The solution of claim 1 , wherein the residual contaminating protein relative to VLP is measured by size exclusion chromatography and ELISA.