Bispecific Antibody Fab CH3 Dimer for Stable Dual-Target Production
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Solution Overview
Problem
Existing bioantibody drugs targeting a single antigen have limitations in efficacy, convenience, and side effects, and there is a need for improved production yield, productivity, solubility, and stability of bi- or multi-target antibodies.
Innovation Solution
A bispecific or multispecific antibody is developed with a CH3 dimer introduced into the Fab region, comprising arms with VH1-CHa-Fc1 and VL1-CLb for one antigen and VH2-CH1-Fc2 and VL2-CL for another antigen, with CHa and CLb forming a dimer and Fc1 linked to Fc2 to form a heavy-chain constant region dimer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single target antibody backbone (IgG1 or IgG4) is used, then the antibody structure is simple and easy to produce, but the efficacy is limited for diseases requiring multiple target mechanisms
Solution Approach 1:
The antibody is divided into two functional arms (first arm and second arm), each capable of binding to different antigens. The first arm includes VH1-CHa-Fc1 and VL1-CLb, while the second arm includes VH2-CH1-Fc2 and VL2-CL, allowing the antibody to simultaneously target multiple antigens while maintaining production simplicity through modular design
Solution Approach 2:
The antibody molecule is designed to perform multiple functions by incorporating two different antigen-binding arms. The Fc1 and Fc2 regions can be linked to form a heavy-chain constant region dimer, enabling the single antibody molecule to engage with two different antigen targets, thus achieving multi-functionality while maintaining a relatively simple IgG-like structure
2Reliability
If combination therapy of two monoclonal antibodies is used, then the therapeutic coverage is improved, but the convenience and side effect profile deteriorate
Solution Approach 1:
Two separate monoclonal antibody functions are merged into a single bispecific antibody molecule. The first arm targets the first antigen while the second arm targets the second antigen, allowing combination therapy effects to be achieved through a single agent, thereby improving treatment convenience and potentially reducing side effects associated with multiple injections
3Adaptability or versatility
If conventional bispecific antibody formats are used, then the ability to bind two targets is achieved, but the production yield, productivity, solubility, aggregation, and stability are insufficient
Solution Approach 1:
The CHa and CLb regions are specifically engineered with local structural modifications to form a dimer, creating a stable Fab region structure. This local quality enhancement at the Fab region (through CH3 dimer introduction) improves overall antibody stability and solubility without compromising the multi-target binding capability of the variable regions
Solution Approach 2:
The antibody incorporates a composite structure combining IgG constant regions (CH1, CH2, CH3) with engineered CHa and CLb regions that form dimers. This composite design integrates the stability of conventional IgG structures with enhanced solubility and reduced aggregation properties, achieving both productivity and versatility
Data Source
AI summary
The present invention relates to a bi- or multi-specific antibody in a novel format comprising a polypeptide in which a CH3 dimer has been introduced into a portion of a Fab region. The bi- or multi-specific antibody in the novel format forms heterodimers while exhibiting almost no non-specific binding between heavy chains and light chains, and produces almost no homodimers, and thus can be highly expressed through animal cells. In addition, the bi- or multi-specific antibody can be obtained through a purification process of an existing monoclonal antibody, and has stability equal to or higher than that of the monoclonal antibody.