Bispecific antibody target pair discovery by high-throughput phenotypic screening using in vitro combinatorial Fab...

Area of Science:

• Immunology
• Biotechnology
• Drug Discovery

Background:

• Selecting effective bispecific antibody target combinations is difficult.
• Bispecific antibodies offer unique cellular response modulation.
• Novel screening platforms are needed for bispecific antibody discovery.

Purpose of the Study:

• To develop a high-throughput, combinatorial, phenotypic screening approach for bispecific antibody target discovery.
• To identify novel bispecific antibodies with potent functional activity.
• To demonstrate the utility of the screening platform across diverse therapeutic areas.

Main Methods:

• Utilized a bispecific antibody target discovery format enabling screening of hundreds of target combinations.
• Generated thousands of bispecific antibodies via simple *in vitro* mixing of Fab-fusion proteins.
• Employed short-term flow cytometry signaling assays and long-term, high-content imaging assays for phenotypic screening.
• Conducted mechanistic screens evaluating functional modulation of peripheral blood mononuclear cell subsets.

Main Results:

• Identified a bispecific antibody co-targeting CD79a/b and CD22 that inhibits human B cell activation.
• Discovered anti-integrin bispecific inhibitors of human cell matrix accumulation targeting integrins β1/β6 or αV/β1.
• Confirmed functional activity conservation from screening format to therapeutic format.
• Identified bispecific antibodies for T cell activation (oncology, infectious disease) and T cell abrogation (autoimmune, inflammatory disease).

Conclusions:

• The described bispecific antibody target pair discovery technology provides access to new target biology.
• This platform enables the development of unique bispecific therapeutics for diverse disease indications.
• The screening approach is versatile for identifying functional bispecific antibodies for various applications.