Humanized Antibody Framework Selection by Tiered Residue Matching
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Solution Overview
Problem
The existing methods for humanizing antibodies often fail to maintain the integrity of the antigen-binding site and result in a loss of antigen-binding activity due to the transfer of CDRs alone, without adequate consideration for the acceptor framework residues, leading to inconsistent affinity and functionality of humanized antibodies.
Innovation Solution
A method is developed to select appropriate human acceptor framework regions for non-human donor antibodies by performing homology alignments and transferring CDRs onto these frameworks, allowing for the production of humanized antibodies with high affinity by utilizing the entire range of variable regions, including the Kabat numbering system for residue selection and weighting of Tier 1 and Tier 2 residues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If CDRs alone are transferred from non-human donor antibodies to human acceptor frameworks, then the humanization process is simplified and faster, but the integrity of the antigen-binding site is not maintained and antigen-binding activity is lost
Solution Approach 1:
The patent applies local quality by selectively modifying specific framework residues (Tier 1 and Tier 2) rather than the entire framework. Tier 1 residues (positions 24, 49, 71, 73, 78, 93 in VH and 46, 48, 58 in VL) are critical for CDR conformation and are prioritized for matching. This localized approach maintains antigen-binding integrity while keeping the humanization process efficient.
Solution Approach 2:
The patent employs preliminary action by pre-identifying and classifying framework residues into tiers based on their importance to CDR conformation before the actual CDR grafting occurs. This preliminary classification (Tier 1: critical, Tier 2: important, Tier 3: less critical) guides the selection of acceptor frameworks and predicts which humanized antibodies will maintain binding activity, reducing the need for extensive screening.
2Reliability
If multiple donor antibodies are screened to find appropriate acceptor frameworks, then the affinity and functionality of humanized antibodies are improved, but the time and resources required for screening increase
Solution Approach 1:
The patent replaces the mechanical/screening-based approach with a computational/predictive system. Instead of empirically screening multiple donor-acceptor combinations, the method uses homology alignment algorithms and tier-based residue classification to predict which acceptor frameworks will preserve binding activity. This substitution dramatically reduces screening time while maintaining high functionality.
Solution Approach 2:
The patent performs preliminary homology alignment and tier classification of framework residues before conducting actual humanization experiments. By pre-identifying acceptor frameworks with high sequence identity in Tier 1 and Tier 2 regions, the method narrows down the candidate pool significantly, reducing the number of antibodies that need to be expressed and screened experimentally.
3Stability of the object's composition
If framework residues are altered to match donor sequences, then the three-dimensional structure of the antigen-binding site is maintained, but the complexity of the humanization protocol increases
Solution Approach 1:
The patent segments the framework residues into three distinct tiers based on their functional importance: Tier 1 (critical for CDR conformation), Tier 2 (important for structure), and Tier 3 (less critical). This segmentation allows researchers to focus modifications on the most critical residues while accepting variations in less important regions, simplifying the overall protocol while maintaining structural integrity.
Solution Approach 2:
The patent applies local quality by making selective modifications only at specific framework positions (Tier 1 and Tier 2 residues) rather than attempting to match the entire donor framework. This localized matching approach maintains the essential three-dimensional structure of the antigen-binding site while reducing the number of modifications required compared to comprehensive framework matching.
4Manufacturing precision
If extensive screening of intermediate chimeric antibodies is performed, then high-affinity humanized antibodies are obtained, but the production process becomes longer and more resource-intensive
Solution Approach 1:
The patent replaces extensive empirical screening with a computational prediction system based on homology alignment and tier-based residue analysis. By calculating sequence identities in Tier 1 and Tier 2 regions and predicting structural compatibility, the method identifies high-affinity candidates in silico before expression, dramatically reducing the number of antibodies that need to be produced and screened experimentally.
Solution Approach 2:
The patent performs preliminary computational assessment of potential humanized antibodies using homology alignment and tier classification before actual production. This preliminary action identifies the most promising candidates based on framework residue matching, allowing researchers to focus resources on expressing and characterizing only those antibodies most likely to achieve high affinity, thereby improving overall production efficiency.
Data Source
AI summary
The present invention relates to improved methods for the selection of appropriate human acceptor framework regions for non-human (donor) antibodies and methods for obtaining humanized antibodies of high affinity using such acceptor frameworks.