Quantifying Heavy and Light Chain Pairing Selectivity
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Solution Overview
Problem
Forming bi-specific IgG antibodies with correctly paired antibody heavy chains and light chains is challenging due to their promiscuous binding nature, leading to minor production of the desired bi-specific antibody format.
Innovation Solution
A high-throughput method for quantifying the selectivity of heavy chain polypeptides pairing with light chain polypeptides, involving co-expression of constructs, isolation, and detection using techniques like ELISA, SPR, or FACS to identify specific pairings and determine selective formation of Fab-containing constructs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If antibody heavy chains and light chains are co-expressed to form bi-specific antibodies, then the desired bi-specific antibody can be produced, but multiple incorrect antibody molecules are also produced due to promiscuous pairing
Solution Approach 1:
The patent modifies the pairing parameters of antibody chains by introducing engineered interfaces with specific binding affinities. By changing the molecular recognition parameters through protein engineering, the system achieves selective pairing where heavy chains preferentially bind to their intended light chains rather than pairing promiscuously, thus improving manufacturing precision while maintaining productivity
Solution Approach 2:
The patent employs engineered interface regions as intermediaries that mediate specific interactions between heavy and light chains. These engineered interfaces act as selective mediators that facilitate correct pairing while preventing incorrect associations, resolving the contradiction between producing desired antibodies and avoiding incorrect pairings
2Adaptability or versatility
If standard co-expression methods are used for heavy and light chains, then multiple antibody variants are produced, but the desired bi-specific format is formed only in minor amounts
Solution Approach 1:
By engineering the pairing interface parameters, the patent shifts the distribution of antibody variants toward the desired bi-specific format. The modified interaction parameters ensure that when heavy and light chains are co-expressed, the majority of molecules form the correct pairing rather than diverse incorrect variants, thus increasing the quantity of desired product while maintaining system versatility
3Ease of manufacture
If heavy chains and light chains with promiscuous binding are used, then co-expression is simple, but selective pairing cannot be achieved
Solution Approach 1:
The patent maintains the simplicity of co-expression by using standard expression systems but changes the binding parameters of the antibody chains themselves. By engineering specific binding affinities and selectivities at the molecular level, the system achieves selective pairing without complicating the manufacturing process, thus resolving the contradiction between ease of manufacture and pairing precision
Data Source
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Figure 3A~3B
AI summary
Provided is a method of quantitatively determining the ability of individual IgG heavy chains to selectively pair with a particular IgG light chain when the heavy chains and two unique light chains are co-expressed. The method provides results with reasonable throughput and is robust and accurate. The co-expressed heavy and light chains do not need to be isolated and purified which enables more efficient screening.