Bispecific IgG Engineering Services

Based on the advanced antibody engineering technology platform, Creative Biolabs provides first-class bispecific IgG engineering services, including bispecific IgG generation service and appended IgGs generation service. We utilize mature technology and rich experience to deliver high-quality bispecific antibody (BsAb) service to accelerate your scientific breakthroughs with precision and reliability.

Features of Bispecific IgGs

Bispecific IgGs are a widely used format of BsAbs that maintain the general size and structure of conventional IgGs. They share similar biophysical properties with regular IgGs, including high serum stability, long half-life, and effective tissue penetration. Bispecific IgGs contain the Fc region, which can be engineered to adjust effector functions. They are typically generated through recombinant expression or hybrid-hybridoma technology. Their IgG-like nature makes them a versatile platform for therapeutic applications, combining dual-antigen targeting with established IgG benefits.

Symmetric Bispecifics

Symmetric BsAbs maintain the IgG-like HC₂LC₂ format, augmented with additional binding domains for a second antigen. These typically result in tetravalent 2+2 bispecifics, but hexavalent 2+4 forms exist via double fusions. Common formats include scFv-IgG, tandem scFv-Fc, sdAb-IgG fusions, and tetra-VH IgG.

Their key advantage is simplified assembly, requiring expression of only one or two polypeptide chains, reducing optimization complexities compared to asymmetric bsAbs. The HC₂LC₂ structure minimizes misassembly risks. Selecting appropriate exogenous antigen-binding domains is crucial. ScFvs are traditional choices, but smaller sdAbs gain traction due to their monomeric nature, avoiding aggregation issues seen with scFvs. Glycine-serine linkers, or those derived from natural antibody linkers, are used for flexible and stable fusions. The modular nature of antibodies permits diverse fusion locations, enabling tailored structural designs.

Fig.1 Various formats of symmetrical BsAbs.¹

Asymmetric Bispecifics

Asymmetric BsAbs are engineered to ensure each half of the antibody binds a different antigen, avoiding unwanted homodimer formation. Asymmetric bispecifics, closely resembling the native molecular geometry of IgG, offer excellent drug-like properties. Their architecture provides flexibility in valencies, enabling monovalent (1+1) or trivalent (2+1) formats, beyond the standard bivalent Y-shape. This flexibility allows for tailored therapeutic effects. The high structural similarity to natural IgGs is believed to minimize immunogenicity risks, enhancing safety. However, achieving this asymmetry requires complex engineering to ensure proper heavy and light chain pairing, a key challenge in their development.

Fig.2 Various formats of asymmetrical BsAbs.¹

Technologies for Heterodimerization

HC:HC pairing

This refers to the pairing of HC with another HC. This is typically observed in some forms of BsAb engineering where two HC chains interact or are designed to pair together in a specific manner. In antibody engineering, controlling this kind of pairing can help generate antibodies with unique functionalities.

HC:LC pairing

This involves the pairing of the HC with the LC. In traditional antibodies, the heavy and light chains naturally pair to form the antigen-binding site. In engineered antibodies, careful manipulation of HC:LC pairing can be used to ensure proper folding and function, as well as to design BsAbs and other complex formats.

Alternative chain steering

This is a method used to control which chains (usually the heavy and light chains) pair together in the correct way. In some cases, it is difficult to achieve the correct HC:LC pairing due to mispairing or aggregation. Alternative chain steering can be used to guide the chains into the correct configuration, ensuring the desired heterodimerization.

Published Data

1. Development of a Symmetric, Bivalent IgG-Like Bispecific Through Bringing the HC to LC

This study introduced a near-native IgG antibody format, the 2xVH, which enables bivalency for any epitope or target without requiring cognate chain pairing engineering. In this design, two distinct VH domains with unique binding specificities were integrated into the CH1 and CL domains, giving the molecule dual specificity. Researchers analyzed the expression, binding, and stability of multiple human VH domains, generating prototype 2xVH IgG and Fab molecules by incorporating these domains into an IgG scaffold. These molecules exhibited similar properties to mAbs, avoiding post-expression purification while maintaining dual binding. The 2xVH format addresses manufacturing limitations of IgG-like bispecifics while enabling biologically relevant dual target engagement.

Fig.3 Bispecific IgG-based formats and overview of 2xVH IgG and Fab format.²

As a trusted partner in the field of BsAb services, Creative Biolabs offers bispecific IgG design, manufacture, and analysis services for your research. Our experts can design BsAbs in multiple formats and species to meet the unique needs of each customer.