Engineering of acidic pH-responsive anti-CD3 binding antibodies

Area of Science:

• Biotechnology
• Immunology
• Computational Biology

Background:

• Anti-CD3 antibody therapeutics offer promise for cancer treatment but face challenges with tumor specificity.
• Tumors exhibit an acidic microenvironment (pH ~6.5-6.8) distinct from healthy tissues (pH ~7.4).
• Engineering conditional pH-dependent binding affinities is a strategy to enhance tumor targeting.

Purpose of the Study:

• To engineer pH-dependent antibody binders targeting the human CD3 antigen.
• To investigate the molecular mechanisms underlying pH-responsiveness in CD3 binders.
• To develop T cell engagers with preferential activity in acidic tumor environments.

Main Methods:

• Utilized molecular dynamics (MD) simulations to analyze the pH-responsiveness of CD3ɛ antibody binder 40G5c.
• Focused on key mutations and their structural impact at varying pH levels.
• Engineered novel CD3 binders with conditional pH-dependent binding.

Main Results:

• MD simulations provided insights into the molecular mechanisms of pH-responsiveness in antibody binders.
• Demonstrated that engineered CD3 binders preferentially bind and activate T cells under acidic conditions.
• Characterized favorable affinity and pH-window profiles for the developed binders.

Conclusions:

• Molecular dynamics simulations are valuable tools for guiding antibody engineering and understanding pH-dependent mechanisms.
• Engineered pH-sensitive CD3 binders offer a promising strategy for tumor-specific T cell engager therapies.
• This approach has the potential to improve cancer treatment by enhancing efficacy and reducing off-tumor toxicity.