Discovery of selective small-molecule CD80 inhibitors

Area of Science:

• Immunology and Drug Discovery
• Molecular and Cellular Biology

Background:

• Protein-protein interactions regulate critical cellular events and are implicated in diseases like autoimmunity and cancer.
• The CD80-CD28 costimulatory pathway is vital for immune response regulation, making it a therapeutic target for autoimmune diseases.

Purpose of the Study:

• To identify small chemical compounds capable of disrupting the CD80-CD28 protein-protein interaction.
• To discover potent and selective inhibitors of the CD80-CD28 pathway for potential immunomodulatory drug development.

Main Methods:

• Employed a cell-based scintillation proximity assay for initial screening of compounds.
• Utilized secondary screening, including biosensor surface analysis, to confirm selective CD80 binding.
• Performed structure-activity relationship studies on derivatives to optimize inhibitor potency and identify key chemical features.

Main Results:

• Identified low-molecular-weight compounds that specifically inhibit the CD80-CD28 interaction.
• Confirmed high selectivity of identified compounds as CD80 binders.
• Achieved a 10-fold increase in binding affinity for CD80 inhibitors through optimization.

Conclusions:

• The study successfully identified potent and selective small-molecule inhibitors of the CD80-CD28 interaction.
• These identified compounds represent promising starting points for developing novel immunomodulatory drugs.
• The findings support targeting the CD80-CD28 pathway for therapeutic intervention in autoimmune conditions.