Heterodimeric IgG1 pI Engineering for Homodimer Purification
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Solution Overview
Problem
Existing methods for producing heterodimeric antibodies result in significant production of undesirable homodimers, necessitating complex purification steps, and there is a need to extend the serum half-life of antibodies by altering the constant domains without affecting antigen binding affinity or introducing immunogenicity.
Innovation Solution
Engineering heterodimeric antibodies with variant heavy and light chain constant regions that have isoelectric points (pIs) at least 0.5 logs apart, allowing for purification by charge-based methods and reducing serum clearance by modifying the pI through specific amino acid substitutions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional methods are used to produce heterodimeric antibodies, then production is straightforward, but significant amounts of undesirable homodimers are generated requiring complex purification steps
Solution Approach 1:
The patent applies parameter changes by modifying the isoelectric point (pI) of antibody constant domains through specific amino acid substitutions. This creates a pI difference between heterodimeric and homodimeric species, enabling separation based on charge differences. The method changes the physical-chemical parameter (pI) to facilitate purification without affecting antigen binding affinity.
2Manufacturing precision
If complex purification steps are used to remove homodimers, then purity of heterodimers is improved, but production cost and time increase
Solution Approach 1:
The patent modifies the isoelectric point parameter of antibody constant domains to create charge-based separation capability. This allows purification based on pI differences between heterodimers and homodimers, reducing the need for multiple complex purification steps and thereby decreasing purification time while maintaining high purity.
3Duration of action of moving object
If serum half-life is extended by altering constant domains, then antibody persistence in serum is improved, but risk of immunogenicity increases
Solution Approach 1:
The patent applies local quality by making targeted amino acid substitutions specifically in the constant domains of antibodies. These localized modifications alter the isoelectric point and extend serum half-life through FcRn binding enhancement, while the variable regions responsible for antigen binding remain unchanged, thereby minimizing immunogenicity risk.
Solution Approach 2:
The patent changes the isoelectric point parameter of constant domains through specific amino acid substitutions. This parameter modification extends serum half-life by optimizing FcRn binding while maintaining structural similarity to endogenous antibodies, thereby reducing immunogenicity.
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 method enables high-yield purification of desired heterodimers and extends serum half-life of antibodies by altering the constant regions, minimizing immunogenicity and simplifying purification processes.
Implementation Method 1
Engineering heterodimeric antibodies with variant heavy and light chain constant regions that have isoelectric points (pIs) at least 0.5 logs apart, allowing for purification by charge-based methods
Data Source
AI summary
The invention relates generally to compositions and methods for purifying the desired species from a mixture of desired heterodimer and contaminating homodimer immunoglobulin variants by modifying the isoelectric point(s) of the individual chains.