Humanized Antibody CDR Residue Substitution for Reduced Immunogenicity
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Solution Overview
Problem
Current antibody humanization techniques face challenges such as high retention of non-human amino acids, inaccurate homology modeling, and the need for co-crystal structures, which affect the affinity and immunogenicity of humanized antibodies.
Innovation Solution
The method involves creating 'ultra' humanized antibodies by introducing human germline residues into the complementarity determining regions (CDRs) of non-human antibodies, using libraries to screen for antibodies with enhanced human amino acid content and reduced immunogenicity, while maintaining antigen binding affinity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If murine CDRs are grafted onto human antibody frameworks, then humanization is achieved, but antigen binding affinity is severely impaired
Solution Approach 1:
The patent applies local quality by selectively replacing only specific non-human residues in the CDR regions with human germline residues, rather than complete humanization. This targeted approach maintains the critical antigen-binding properties while reducing immunogenicity. The method identifies specific positions in CDR-L1, CDR-L2, CDR-L3, CDR-H1, and CDR-H2 that benefit from human residue substitution while preserving overall binding affinity.
Solution Approach 2:
The patent changes the amino acid composition parameters by introducing human germline residues at specific positions within the CDR regions. This parameter modification increases the human character of the antibody sequence while maintaining structural and functional integrity. The method systematically evaluates and substitutes residues based on their impact on both humanization and binding affinity.
2Reliability
If back-mutations are introduced to restore CDR conformation, then antigen binding is improved, but non-human amino acid content increases
Solution Approach 1:
The patent applies partial action by introducing only a subset of back-mutations that are most critical for maintaining CDR conformation and antigen binding. Rather than restoring all non-human residues, the method selectively introduces human germline residues at positions that provide the necessary structural support while minimizing non-human content. This partial restoration achieves sufficient binding affinity while maintaining high humanization levels.
3Productivity
If homology modeling is used to select framework residues, then humanization process is accelerated, but modeling accuracy is insufficient
Solution Approach 1:
The patent uses homology modeling as an intermediary tool to guide the humanization process, but combines it with empirical validation and iterative optimization. The modeling provides initial predictions of which residues to substitute, but the final selection is refined through experimental testing and structural analysis, ensuring both efficiency and accuracy in the humanization process.
4Adaptability or versatility
If all six murine CDRs are transferred to human framework, then complete humanization is achieved, but T-cell epitope content remains high
Solution Approach 1:
The patent applies local quality by focusing humanization efforts specifically on the CDR regions where T-cell epitopes are most likely to form. By selectively substituting non-human residues in CDR-L1, CDR-L2, CDR-L3, CDR-H1, and CDR-H2 with human germline residues, the method targets the reduction of immunogenic epitopes while preserving antigen-binding functionality in these critical regions.
Data Source
AI summary
Disclosed herein are humanized antibodies in which human germline residues are introduces to the complementarity determining regions (CDRs) of a non-human donor antibody. Also described herein are libraries of antibody variable domains (e.g., phage-display libraries) and methods for screening for humanized antibodies.