Site-specific antibody masking enables conditional activation with different stimuli

Area of Science:

• Biotechnology
• Immunology
• Oncology

Background:

• Antibody therapeutics offer significant disease treatment potential but are limited by off-target side effects.
• Conditionally-active antibodies enhance safety through targeted activation, but current masking strategies lack broad applicability.
• Developing versatile antibody masking is crucial for improving therapeutic selectivity and reducing adverse events.

Purpose of the Study:

• To develop a versatile approach for conditionally masking antibody derivatives.
• To apply this strategy to a single chain variable fragment (scFv) targeting cancer stem cell receptors.
• To engineer antibodies activatable by various internal or external stimuli.

Main Methods:

• Site-specific conjugation of a polymer to an engineered cysteine residue via a chemically-synthesized, cleavable linker.
• Utilizing light (365 nm) or matrix metalloproteinases (MMPs) as stimuli for mask cleavage.
• Evaluating masking efficiency based on conjugation site and mask size.

Main Results:

• Masking efficiency was dependent on conjugation site and polymer size.
• Optimized masking reduced antigen binding by up to 20-fold.
• Antigen binding affinity was fully restored upon activation by light or MMPs.

Conclusions:

• The proposed strategy enables versatile conditional masking of antibody derivatives.
• This approach significantly enhances antibody selectivity and safety for therapeutic applications.
• The method facilitates the rapid engineering of antibodies activatable by diverse stimuli.