Development of a Macrophage-Based ADCC Assay

Area of Science:

• Immunology
• Pharmacology
• Biotechnology

Background:

• Fc-dependent effector functions are crucial for therapeutic antibody efficacy in vivo.
• Existing antibody-dependent cellular cytotoxicity (ADCC) assays often lack throughput, reproducibility, and in vivo relevance.
• Macrophages, rather than NK cells, are increasingly recognized as key mediators of antibody effector functions in vivo.

Purpose of the Study:

• To develop a novel, macrophage-based ADCC assay for improved assessment of therapeutic antibody potency.
• To establish a reliable method for measuring ADCC activity mediated by macrophages.
• To validate the assay's performance using various antibody isotypes and influenza-specific antibodies.

Main Methods:

• Development of a macrophage-based ADCC assay utilizing luciferase-expressing target cells.
• Quantification of ADCC-dependent cell killing by measuring the loss of luciferase signal.
• Validation with diverse mouse and human antibody isotypes against a model antigen-antibody complex.

Main Results:

• The developed assay successfully measured ADCC activity for various antibody isotypes, aligning with known effector functions.
• The assay demonstrated correlation with established in vivo effector functions for influenza-specific antibodies.
• The macrophage-based assay provides a more in vivo-relevant measure of antibody-mediated cytotoxicity.

Conclusions:

• A novel and robust macrophage-based ADCC assay has been developed.
• This assay offers enhanced in vivo relevance for evaluating therapeutic antibodies, particularly those engaging Fc receptors on macrophages.
• The assay serves as a valuable tool for antibody discovery and development, especially for influenza-specific therapeutics.