Antibody Constant Domain Mutations for Serum Half-Life Extension
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Solution Overview
Problem
Current methods for altering the isoelectric point of antibodies to extend serum half-life are unpredictable and often introduce immunogenicity, as they primarily focus on the Fc region or variable regions, without a modular approach to improve pharmacokinetics while minimizing immunogenicity.
Innovation Solution
Introducing specific amino acid mutations in the constant domains of antibodies, such as non-native glutamic acid or cysteine substitutions, to lower the isoelectric point, thereby increasing serum half-life without significant immunogenicity, using a modular approach that can be applied to different antigen binding sequences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If Fc region or variable regions are engineered to alter isoelectric point, then serum half-life is extended, but immunogenicity increases
Solution Approach 1:
The patent systematically varies the isoelectric point parameter of constant domains through specific amino acid substitutions (particularly E211K in IgG1 and analogous positions in other isotypes) to optimize serum half-life while maintaining low immunogenicity. This parameter-based approach allows precise control over pharmacokinetic properties without introducing highly immunogenic variable region changes.
Solution Approach 2:
The invention applies localized modifications specifically to constant domain regions (CH1, CH2, CH3, CL) rather than throughout the entire antibody structure. By confining isoelectric point alterations to specific constant domain positions, the patent achieves pharmacokinetic optimization while preserving the immunologically quiet nature of constant regions, thereby minimizing immunogenicity.
2Duration of action of stationary object
If variable regions are engineered to lower isoelectric point, then serum half-life increases, but binding affinity may be affected
Solution Approach 1:
The patent divides the antibody into functional segments: variable regions for antigen binding and constant regions for pharmacokinetic control. By assigning the isoelectric point modification task to constant domains rather than variable regions, the invention isolates pharmacokinetic optimization from binding function, ensuring that antigen recognition and serum half-life can be independently optimized without compromising either.
Solution Approach 2:
Instead of the conventional approach of modifying variable regions to alter isoelectric point, the patent inverts the strategy by modifying constant domains. This reversal allows pharmacokinetic optimization without interfering with the variable regions' primary function of antigen binding, thereby maintaining binding affinity while achieving extended serum half-life.
3Duration of action of stationary object
If multiple amino acid mutations are introduced to significantly lower isoelectric point, then serum half-life extends by 25-250%, but structural stability may be compromised
Solution Approach 1:
The patent introduces a specific number of targeted amino acid substitutions (typically 1-3 key mutations per constant domain) rather than exhaustive modifications. This partial action approach achieves sufficient isoelectric point reduction to extend serum half-life by 25-250% while maintaining structural integrity, as evidenced by the preservation of normal antibody folding, assembly, and function.
Data Source
AI summary
The invention relates generally to compositions and methods for altering the isoelectric point of an antibody, and in some cases, resulting in improved plasma pharmacokinetics, e.g. increased serum half-life in vivo.