Humanized Anti-CD19 Antibody Framework Optimization
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Solution Overview
Problem
Current antibodies against CD19, primarily murine antibodies, exhibit strong immunogenicity leading to human anti-mouse antibody (HAMA) and anti-antibody reactions, reducing their therapeutic efficacy and stability, and it is challenging to maintain their affinity and specificity after humanization.
Innovation Solution
Development of a humanized antibody against CD19 with specific framework regions that retain high affinity and specificity, avoiding HAMA and AAR reactions, by optimizing the light and heavy chain variable regions and incorporating specific CDR sequences, and using these antibodies in immune effector cells or as part of chimeric antigen receptors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If murine antibodies are used against CD19, then high affinity and specificity are achieved, but strong immunogenicity occurs leading to HAMA and AAR reactions
Solution Approach 1:
The patent applies parameter changes by modifying the amino acid sequence of the antibody framework regions from murine to human origin. Specifically, the framework regions are replaced with human framework regions while retaining the CDR sequences, thereby changing the immunological parameters of the antibody to reduce HAMA and AAR reactions while maintaining binding affinity through optimized framework-CDR interactions
2Object-affected harmful factors
If humanization is performed by replacing murine framework regions with human framework regions, then immunogenicity is reduced, but binding affinity and specificity are decreased by more than 10-fold
Solution Approach 1:
The patent applies local quality by making targeted amino acid substitutions specifically in the framework regions that are critical for CDR conformation and antigen binding. Rather than complete humanization, specific residues are optimized to maintain local structural features necessary for high-affinity binding while still reducing overall immunogenicity. This localized optimization preserves the framework-CDR interactions essential for maintaining binding affinity
Solution Approach 2:
The patent optimizes specific parameters of the framework regions including amino acid composition, charge distribution, and hydrophobicity to maintain stable CDR conformation. By carefully selecting and optimizing these parameters, the antibody achieves both reduced immunogenicity and preserved binding affinity
3Measurement precision
If framework regions are optimized to maintain CDR conformation, then binding affinity is preserved, but the complexity of screening and expressing appropriate framework regions increases
Solution Approach 1:
The patent establishes specific parameter ranges and optimization criteria for framework region selection, including amino acid composition guidelines, charge distribution patterns, and hydrophobicity indices. These defined parameters provide a systematic framework for selecting and optimizing framework regions, reducing the complexity of screening by providing clear selection criteria rather than requiring extensive empirical testing
Data Source
AI summary
Disclosed are an anti-CD19 humanized antibody prepared from a murine monoclonal antibody, a chimeric antigen receptor containing the humanized antibody, and an immune cell expressing the humanized antibody. Not only does the humanized antibody of the present invention not produce an anti-antibody response (AAR) and a human anti-mouse antibody response (HAMA), but same also has better affinity than a murine antibody, and has excellent activity and safety, thereby providing a new means for treating CD19-expressing tumors.