Fc-less Bispecific Antibody Assembly via Segmentation
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Solution Overview
Problem
Current methods for producing bispecific antibodies are hindered by difficulties in achieving high purity and quantity, leading to adverse safety issues, low response rates, and limited effectiveness due to off-target effects and unexpected Fc-mediated effector functions.
Innovation Solution
Development of engineered bi-specific and tri-specific antibodies with fine-tuned combinations of single binding-domain fragments, where the first antigen binding domain is linked to the N-terminal of the heavy chain, and the second or third binding domain is linked to the N-terminal of the light chain, enhancing specificity and affinity for target cells while minimizing binding to normal cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional methods (chemical cross-linking, hybrid-hybridomas, or disulfide exchange) are used to produce bispecific antibodies, then bispecific antibodies can be generated, but manufacturing purity and quantity are insufficient
Solution Approach 1:
The invention segments the antibody production process into separate expression of individual antibody chains (first and second chains) followed by controlled assembly. Each chain is expressed separately in host cells, then assembled through reduction of disulfide bonds to form the bispecific antibody. This segmentation enables independent optimization of each chain's expression and purification, ultimately improving both quantity and purity of the final bispecific product.
Solution Approach 2:
The invention uses a linker molecule as an intermediary to facilitate the assembly of the first and second antibody chains into the bispecific antibody. The linker contains reducing agents that mediate the formation of interchain disulfide bonds, enabling controlled assembly while maintaining high purity. This intermediary approach avoids the need for complex purification steps required by conventional methods.
2Reliability
If high affinity binding is achieved, then target cell binding is enhanced, but off-target effects and adverse safety issues increase
Solution Approach 1:
The invention applies local quality by creating asymmetric antibody structures where the first and second chains have different affinities for their respective targets. The first chain binds to the first target with a specific affinity, while the second chain binds to the second target with a different affinity. This asymmetric design allows the antibody to preferentially bind to double-positive target cells (expressing both targets) while minimizing binding to single-positive or negative cells, thereby reducing off-target effects.
Solution Approach 2:
The invention employs asymmetry in the bispecific antibody structure, where the two arms of the antibody have different binding characteristics. The first arm (comprising the first chain) and second arm (comprising the second chain) are designed with different affinities and specificities. This asymmetric configuration enables selective binding to target cells expressing both antigens, improving therapeutic specificity and reducing adverse effects on normal cells.
3Reliability
If Fc-mediated effector functions are utilized, then therapeutic effectiveness is enhanced, but unexpected safety issues arise
Solution Approach 1:
The invention extracts and removes the Fc region from the antibody structure, creating an Fc-less bispecific antibody. By eliminating the Fc portion, the antibody retains its binding functionality to targets while avoiding unexpected Fc-mediated effector functions such as complement activation or Fc receptor binding that could cause adverse safety issues. The therapeutic effectiveness is maintained through the binding arms, which can still mediate target cell engagement and killing mechanisms.
Data Source
AI summary
The present invention relates to novel multi-specific antibodies comprising fine tuned combination of low affinity single binding domain fragments to selectively target double targets on cancer cell, and use thereof for therapy, such as for guided immunotherapy.