Evaluation of complement-dependent cytotoxicity using ATP measurement and C1q/C4b binding.

Area of Science:

• Immunology
• Pharmacology
• Biochemistry

Background:

• Antibody therapy efficacy is often limited by insufficient effector functions.
• Complement-dependent cytotoxicity (CDC) is a key effector function involving C1q binding to antibody Fc regions, leading to cell lysis.
• Modifications to antibody Fc regions (isotype, genetics, glycosylation) can alter CDC activity.

Purpose of the Study:

• To evaluate the impact of Fc modifications on complement-dependent cytotoxicity (CDC).
• To establish robust methods for assessing CDC induction by therapeutic antibodies.

Main Methods:

• A luminescence-based ATP assay to quantify tumor cell damage.
• Flow cytometry to measure C1q binding to Fc regions and C4b deposition on cell surfaces.
• Combined use of luminescence and flow cytometry for comprehensive CDC evaluation.

Main Results:

• The described luminescence and flow cytometry methods effectively assess antibody-mediated CDC.
• These methods allow for the evaluation of Fc engineering strategies aimed at enhancing CDC.
• The combined approach provides a complete picture of an antibody's ability to trigger CDC.

Conclusions:

• Accurate measurement of CDC is essential for optimizing antibody-based therapeutics.
• The presented luminescence and flow cytometry assays offer a comprehensive platform for evaluating CDC.
• These methods can guide the development of more effective antibody treatments by assessing Fc-mediated effector functions.