ISVD Monomer Purification via Protein A Chromatography
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Solution Overview
Problem
Current Protein A chromatography methods are ineffective in separating antigen-binding polypeptide monomers comprising immunoglobulin single variable domains (ISVDs) from aggregates due to chemical similarity, leading to co-elution of aggregates with monomers and potential exacerbation of aggregate formation during acidic pH treatment.
Innovation Solution
Utilizing TOYOPEARL AF-rProtein A HC-650F or AMSPHERE A3 Protein A resins at neutral pH for equilibration and elution with a pH 3.5 solution to selectively bind and separate aggregates from ISVD monomers, achieving a composition substantially free of aggregates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional Protein A chromatography is used to purify ISVD monomers, then the bulk of impurities are removed, but aggregates co-elute with monomers due to chemical similarity
Solution Approach 1:
The patent applies parameter changes by optimizing the elution pH to 3.5, which is higher than conventional elution pH values (typically 2.0-2.5). This specific pH parameter change creates differential binding behavior where aggregates remain bound to the Protein A resin while monomers elute, achieving separation based on subtle differences in binding affinity at this specific pH condition.
2Productivity
If Protein A elution is performed at low pH to elute monomers, then monomers are recovered, but aggregate formation is exacerbated
Solution Approach 1:
The patent applies preliminary anti-action by performing the elution step at a controlled pH of 3.5 that prevents aggregate formation in the first place. By choosing an elution pH that maintains monomer stability and prevents denaturation, the process counteracts the potential harmful effect of acidic conditions before they can cause aggregation, rather than attempting to correct aggregation after it occurs.
3Manufacturing precision
If additional chromatography steps are added to remove aggregates, then aggregate removal is improved, but process complexity and cost increase
Solution Approach 1:
The patent merges the purification and aggregate removal functions into a single Protein A chromatography step. By optimizing the elution conditions, the process simultaneously achieves both monomer purification and aggregate separation, eliminating the need for additional dedicated aggregate removal steps and reducing overall process complexity.
4Adaptability or versatility
If Protein A resin is used for ISVD purification, then binding occurs via variable domain residues, but binding affinity differs from antibody-Fc interactions
Solution Approach 1:
The patent addresses the variability in binding affinity by precisely controlling the elution pH at 3.5. This parameter optimization compensates for the differences in binding mechanisms between ISVDs and traditional antibodies, ensuring reliable and consistent elution of ISVD monomers while maintaining selective separation from aggregates.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The process effectively reduces aggregate content in the eluted ISVD monomers to less than 5%, with specific embodiments achieving less than 2% or 1.6% aggregates, improving the purity and stability of the final product.
Implementation Method 1
This initial step provides a product that is typically greater than 90% pure, and the subsequent bioprocessing steps are focused on the removal of the remaining minor impurities. Protein A chromatography is fast and easy to use
Implementation Method 2
Protein A chromatography can effectively remove a significant amount of contaminants from the antibody preparation, it does not effectively remove aggregates already present in the feedstock because of the chemical similarity of aggregates to the single antibody molecule
Data Source
AI summary
A method that uses Protein A chromatography to separate antigen-binding polypeptide monomers comprising one or more immunoglobulin single variable domains (ISVDs) from aggregates of said monomers is disclosed.