Modified IgG4 Antibodies for Stable Heterodimerization
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Solution Overview
Problem
Current multispecific antibodies face challenges in achieving desired heterodimerization while minimizing effector functions and chain exchange reactions, particularly with IgG4, which affects their stability and immunogenicity, leading to unwanted inflammatory responses and immune reactions.
Innovation Solution
Development of multispecific antibodies with modified human IgG4 constant regions, such as those with mutations S228P, F234A, L235A, and T366W, and T366S, L368A, Y407V, which facilitate heterodimer formation and reduce effector functions, combined with a heavy chain-only variable domain configuration to minimize chain exchange and enhance specificity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If IgG4 constant region is used in multispecific antibodies, then effector function activity is reduced, but chain exchange reactions occur due to hinge region sequence
Solution Approach 1:
The patent applies parameter changes by modifying the amino acid sequence of the IgG4 hinge region through site-directed mutagenesis. Specific residues in the hinge region are mutated to alter the chemical and physical properties of the constant region, thereby preventing chain exchange reactions while preserving the low effector function characteristics of IgG4.
Solution Approach 2:
The patent applies local quality by making targeted modifications only to the hinge region of the IgG4 constant region, leaving other parts of the antibody structure unchanged. This localized approach allows the patent to address the specific problem of chain exchange reactions without affecting the overall low effector function profile of the IgG4 antibody.
2Manufacturing precision
If amino acid modifications are introduced to facilitate heterodimerization, then pairing specificity is improved, but immune response is induced due to non-native sequences
Solution Approach 1:
The patent uses parameter changes by introducing specific amino acid substitutions in the CH2 and CH3 domains that create knobs-into-holes interfaces. These modifications alter the steric and electrostatic parameters of the Fc region to enforce heterodimerization while maintaining overall structural similarity to native IgG4, thereby reducing immunogenicity.
Solution Approach 2:
The patent applies copying by creating modified versions of the native IgG4 constant region that closely resemble the original sequence. The modifications are minimal and strategically placed to achieve heterodimerization without creating highly foreign structures that would trigger strong immune responses.
3Object-generated harmful factors
If amino acid modifications are introduced to reduce effector functions, then unwanted inflammatory responses are reduced, but heterodimerization efficiency is affected
Solution Approach 1:
The patent applies local quality by making targeted modifications to specific residues in the Fc region that are responsible for effector function mediation, while preserving the overall Fc structure required for heterodimerization. This allows selective reduction of inflammatory responses without compromising pairing efficiency.
Solution Approach 2:
The patent uses parameter changes by modifying specific amino acid residues that control effector function binding interfaces, such as glycosylation sites and Fc receptor binding regions. These parameter modifications reduce inflammatory activity while maintaining the structural integrity needed for heterodimer formation.
Data Source
Figure 1A~1C
Figure 2A~2B
Figure 3A~3B
AI summary
Multispecific, human heavy chain antibodies (e.g., UniAbsTM) that have modified heavy chain constant regions that impart advantageous properties are provided. The invention further concerns methods of making such antibodies, compositions, including pharmaceutical compositions, comprising such antibodies, and their use to treat disorders that are characterized by expression of one or more of the binding targets described herein.