Generation of mixed-valency, modular multispecific antibodies using disulfide-linked Fc-FcγR complexes

Area of Science:

• Biotechnology
• Immunology
• Protein Engineering

Background:

• Multispecific antibodies offer therapeutic advantages but face challenges in design and production.
• Current engineering methods for multispecific antibodies are complex and bespoke.

Purpose of the Study:

• To develop a simplified, universal platform for engineering multispecific antibodies.
• To repurpose the native Fc-FcγR interaction into a covalent docking site.

Main Methods:

• Engineered a single disulfide bond between Fc and FcγRIIIa to create a stable, covalent complex.
• Utilized the FcγR termini for independent functionalization with various payloads (e.g., anti-CD3, IL-2).
• Compatible with standard mammalian expression systems without post-expression modification.

Main Results:

• Generated stable, covalently linked Fc-FcγR complexes.
• Demonstrated successful incorporation of diverse payloads, including masked formats.
• Exhibited potent, antigen-selective cytotoxicity in vitro and in vivo.
• Showcased tunable avidity and reduced off-target activity.

Conclusions:

• The developed platform provides a simple, plug-and-play solution for multispecific antibody design.
• This method overcomes key developability bottlenecks, enabling rapid and scalable creation of next-generation antibody therapeutics.