Split Ig Domain Heterodimerization for Antibody Chain Pairing
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Solution Overview
Problem
Current methods for producing bispecific antibodies face challenges in achieving correct pairing of different chains, particularly the 'light chain pairing problem', leading to unwanted mispaired products and reduced plasma half-life due to the absence of the Fc domain, which affects their efficacy and stability.
Innovation Solution
The use of novel heterodimerization domains derived from split immunoglobulin (Ig) domains, specifically comprising N-terminal and C-terminal β-strands of an Ig domain, enables specific dimerization of polypeptides, ensuring correct pairing of heavy and light chains without unwanted by-products and enhancing plasma half-life by reassembling into complete Ig domains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If heterodimeric bisspecific antibodies are generated by coexpression of two expression cassettes each comprising a heavy chain and a light chain, then bisspecific antibodies can bind two different targets simultaneously, but many unwanted mispaired side products are formed due to the heavy chain pairing problem
Solution Approach 1:
The invention divides the antibody chain pairing problem into separate heterodimerization domains. By introducing distinct heterodimerization domains (HD1 and HD2) that specifically recognize and bind to each other, the heavy chains are segmented into pairs that can only form the desired heterodimer configuration, preventing mispairing while maintaining bispecific functionality.
Solution Approach 2:
The invention introduces heterodimerization domains as intermediary structures that mediate specific pairing between heavy chains. These domains act as molecular mediators that facilitate correct chain association through specific protein-protein interactions, ensuring that only the intended heterodimer pairs form during coexpression.
2Ease of manufacture
If the Fc domain is absent in bisspecific antibodies, then the antibodies are smaller and can be produced in microbial systems, but they do not evoke antibody-dependent cell-mediated cytotoxicity (ADCC) or complement-dependent cytotoxicity (CDC) and have much shorter plasma half-lives
Solution Approach 1:
The invention applies local quality by differentially modifying the N- and C-terminal regions of the antibody chains. The N-terminal region retains the antigen-binding variable domains for microbial production compatibility, while the C-terminal region incorporates heterodimerization domains that provide Fc-like stability and half-life extension without requiring the full Fc domain structure.
Solution Approach 2:
The invention creates a composite antibody structure combining antigen-binding variable domains with heterodimerization domains. This composite design integrates the advantages of small, microbially-producible antibody fragments with the stability and half-life characteristics of Fc-containing antibodies, achieving both ease of manufacture and reliable effector functions.
3Ease of operation
If one uses a common light chain to address the light chain pairing problem, then pairing is simplified, but this approach is not feasible in all cases
Solution Approach 1:
The invention creates a universal heterodimerization domain system that can be applied across different antibody formats and applications. The heterodimerization domains serve multiple functions: ensuring correct heavy chain pairing, enabling bispecific binding, and providing stability, making the approach universally applicable regardless of the specific antigen targets or light chain configurations.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach minimizes undesired chain pairings and extends the plasma half-life of bispecific antibodies, improving their stability and efficacy by ensuring precise assembly and interaction with Fc receptors and complement systems.
Implementation Method 1
HDA and HDB bind to each other wherein one heterodimerization domain comprises or consists of two N-terminal β-strands (N-β) of an immunoglobulin (Ig) domain and the other heterodimerization domain comprises or consists of two C-terminal β-strands (C-β) of an Ig domain
Data Source
AI summary
The invention relates to a protein complex comprising at least two polypeptide chains A (PCA) and B (PCB), wherein PCA comprises a heterodimerization domain A (HDA) and PCB comprises a heterodimerization domain B (HDB), wherein HDA and HDB bind to each other and wherein one heterodimerization domain comprises or consists of two N-terminal β-strands (N-β) of an immunoglobulin (Ig) domain and the other heterodimerization domain comprises or consists of two C-terminal β-strands (C-β) of an Ig domain. The invention further relates to polynucleotides encoding one or more polypeptides of the protein complex, expression vectors comprising the polynucleotides and a cell comprising the polynucleotides or the expression vectors.