AAV Harvesting via Supernatant Extraction
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Solution Overview
Problem
Current methods for producing Adeno-associated virus (AAV) require cell disruption and collection of cell pellets, leading to low efficiency and purity due to the release of intracellular proteins and debris, necessitating large quantities of producing cells and complex purification processes.
Innovation Solution
A method for producing AAV by modifying the capsids, cells, and culture conditions to reduce binding between AAV and producer cells, allowing AAV to be harvested from the supernatant without cell disruption, resulting in higher purity and yield, and enabling continuous production without the need for cell lysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If cell disruption and cell pellet collection methods are used for AAV production, then AAV can be obtained from producing cells, but intracellular proteins and debris are released leading to low purity and requiring complex purification processes
Solution Approach 1:
The patent extracts only the necessary component (AAV) from the production system by harvesting it from the supernatant, leaving the problematic intracellular components (proteins and debris) behind in the cells. This is achieved by modifying AAV capsids to prevent binding to producer cells, allowing selective extraction of AAV without co-extraction of contaminants.
Solution Approach 2:
The patent segments the AAV production system into two separate harvestable components: AAV in the supernatant and cellular material in the pellet. By preventing AAV binding to cells through capsid modification, the system allows supernatant harvesting containing pure AAV, while cellular contaminants remain segregated in the discarded pellet.
2Productivity
If cell disruption methods are used to release AAV from producer cells, then AAV can be harvested, but the process requires large quantities of producing cells and results in low production efficiency
Solution Approach 1:
The patent enables continuous AAV production by allowing repeated harvesting from the same supernatant without cell disruption. The modified capsids maintain their non-binding properties across multiple harvest cycles, allowing continuous extraction of AAV from the culture medium while maintaining high production efficiency.
Solution Approach 2:
The patent changes the binding parameter of AAV capsids to producer cells by modifying capsid structure or culture conditions. This parameter change transforms AAV from a cell-bound state to a free-floating state in supernatant, dramatically improving harvestability and production efficiency without requiring large cell quantities.
3Stability of the object's composition
If AAV binding to producer cells is strong, then AAV remains associated with cells during production, but this requires cell collection and disruption leading to contamination with intracellular materials
Solution Approach 1:
The patent inverts the traditional approach by preventing AAV binding to cells rather than relying on strong binding. Instead of harvesting AAV from disrupted cells, the method allows AAV to remain free in the supernatant through capsid modification, reversing the conventional wisdom that strong cell association is necessary for production.
Data Source
AI summary
A method for producing AAV, without requiring cell lysis, is described. The method involves harvesting AAV from the supernatant. For AAV having capsids with a heparin binding site, the method involves modifying the AAV capsids and/or the culture conditions to ablate the binding between the AAV heparin binding site and the cells, thereby allowing the AAV to pass into the supernatant, i.e., media. Thus, the method of the invention provides supernatant containing high yields of AAV which have a higher degree of purity from cell membranes and intracellular materials, as compared to AAV produced using methods using a cell lysis step.