Ligand-Directed GPCR Antibody Discovery

Area of Science:

• Biotechnology
• Immunology
• Pharmacology

Background:

• Developing affinity reagents for G-protein coupled receptors (GPCRs) is difficult using traditional methods.
• Existing anti-GPCR antibodies often lack functional modulation and have low development success rates.
• Current antibody development pipelines prioritize affinity over functional epitope recognition.

Purpose of the Study:

• To develop a new strategy for generating functional antibodies targeting GPCRs and other challenging cell surface proteins.
• To create antibody libraries with an inherent bias towards the active site of GPCRs using natural ligand affinity.
• To rapidly generate both agonist and antagonist antibodies against high-value targets with poor epitope exposure.

Main Methods:

• Generated focused antibody libraries incorporating natural ligands within or conjugated to antibody regions.
• Employed a two-round randomization strategy: first, limiting randomization to non-ligand-carrying regions, then randomizing the ligand-carrying part.
• Tested the pipeline on three different GPCR targets.

Main Results:

• Successfully generated functional antibodies (agonists and antagonists) against three GPCR targets.
• Demonstrated the pipeline's ability to overcome challenges associated with poor functional epitope exposure.
• Validated the approach for generating antibodies against GPCRs, channels, transporters, and glycosylated cell surface targets.

Conclusions:

• The proposed pipeline enables rapid generation of functional antibodies against difficult-to-target proteins.
• This strategy overcomes limitations of traditional methods for developing GPCR-targeting antibodies.
• The approach is applicable to a broad range of high-value therapeutic targets with masked binding sites.