Deimmunized VNAR Scaffolds for Reduced Immunogenicity
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Solution Overview
Problem
Shark VNAR domains pose a challenge for humanization due to structural differences and low sequence identity with human V domains, leading to immunogenicity issues when used therapeutically.
Innovation Solution
Deimmunization of VNAR scaffolds by identifying and removing human T-cell epitopes from MHC Class II binding sites through in silico analysis and subsequent amino acid substitutions, deletions, or insertions, maintaining the overall structure and antigen binding capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If VNAR scaffolds are used therapeutically, then high affinity and cross-reactivity with target antigens is achieved, but immunogenicity increases due to structural differences and low sequence identity with human V domains
Solution Approach 1:
The patent applies local quality by making targeted amino acid substitutions specifically in framework regions 1, 2, and 4 of the VNAR scaffold while preserving the CDR regions. This localized modification approach reduces immunogenicity in specific areas without affecting the overall antigen-binding functionality of the variable domain.
Solution Approach 2:
The patent implements parameter changes by systematically altering the amino acid sequence parameters of the VNAR scaffold. Specific residues in framework regions are mutated to reduce similarity to shark-derived sequences and minimize MHC class II binding, thereby changing the immunogenic parameters while maintaining structural integrity and binding affinity.
2Object-affected harmful factors
If framework residues are replaced to reduce immunogenicity, then MHC class II binding is reduced, but antigen binding capacity is dramatically lost
Solution Approach 1:
The patent carefully distinguishes between framework regions and CDR regions, applying modifications only to framework regions 1, 2, and 4 while leaving the CDR regions intact. This localized approach ensures that antigen-binding properties are preserved while reducing immunogenic framework sequences.
Solution Approach 2:
The patent applies partial action by selecting specific residues within framework regions for mutation rather than replacing entire framework regions. This selective modification of key residues achieves sufficient reduction in MHC class II binding while minimizing impact on overall structure and antigen binding.
3Reliability
If extensive paratope re-engineering is performed to maintain binding after framework replacement, then binding capacity is partially restored, but structural complexity and development time increase
Solution Approach 1:
The patent performs preliminary action by pre-identifying and optimizing framework region residues before CDR grafting. The framework is engineered in advance to have reduced immunogenicity, which simplifies subsequent paratope optimization and reduces the need for extensive iterative re-engineering of the antigen-binding regions.
Data Source
AI summary
The present disclosure relates to deimmunized VNAR scaffolds, methods of making the scaffolds and their use as frameworks, and VNAR domains comprising those scaffolds, especially therapeutic VNAR domains to a target antigen of interest, including, for example, high affinity VNAR domains that are cross reactive with primate transferrin receptors (“TfR”) as well as other VNAR domains capable of carrying a therapeutic or diagnostic cargo across the blood brain barrier.