Engineered protease-resistant antibodies with selectable cell-killing functions

Area of Science:

• Biotechnology
• Immunology
• Protein Engineering

Background:

• Monoclonal antibody therapeutics, primarily IgG1 scaffolds, face degradation by proteases in tumor microenvironments.
• Proteolytic cleavage in the IgG1 hinge region can abolish Fc-mediated cell-killing functions while preserving antigen binding and half-life.
• This cleavage is a mechanism for tumors and microbes to evade host immune responses.

Purpose of the Study:

• To engineer novel antibody scaffolds resistant to protease degradation.
• To restore or enhance Fc-mediated cell-killing functions in protease-resistant antibodies.
• To develop a versatile platform for protease-resistant antibody therapeutics with selective cytotoxicity.

Main Methods:

• Engineering mutations in the CH2 domain and lower hinge region of IgG1 antibodies.
• Assessing protease resistance of engineered antibodies.
• Evaluating Fc-mediated functions, including complement-dependent cytotoxicity (CDC) and Fcγ receptor (FcγR)-mediated cellular cytotoxicity.

Main Results:

• Mutations in the CH2 domain, combined with lower hinge mutations, conferred protease resistance.
• These combined mutations restored and sometimes enhanced Fc-mediated cell-killing functions.
• The developed antibody platform demonstrated selective cell-killing capabilities while maintaining protease resistance.

Conclusions:

• Novel antibody engineering strategies can overcome protease-mediated evasion mechanisms.
• The developed protease-resistant antibody platform offers a promising approach for next-generation antibody therapeutics.
• This platform enables the design of antibodies with tailored, potent, and selective cell-killing functions for therapeutic applications.