Optimized cytotoxicity assay for co-suspended effector and target cells

Area of Science:

• Immunology
• Cell Biology
• Biotechnology

Background:

• Adoptive cell therapies, including CAR-T, NK, and CTL cells, are increasingly used in clinical settings.
• CD19 CAR-T cell therapy is FDA-approved for certain lymphomas.
• Accurate assessment of cellular cytotoxicity and immune cell quality is crucial before patient infusion.

Purpose of the Study:

• To develop and validate a reliable method for detecting cellular cytotoxicity and monitoring immune cell quality.
• To overcome limitations of conventional assays, such as target cell proliferation and interference from non-specific dyes.
• To optimize a cytotoxicity assay for routine quality control of ex vivo expanded immune cells.

Main Methods:

• Modification of a coincubation medium component to stabilize a specific assay window.
• Optimization and validation of the Europium-TDA (Eu-TDA) method for cytotoxicity detection.
• Comparison of the optimized Eu-TDA method with lactate dehydrogenase (LDH) detection.

Main Results:

• The modified medium component stabilized the assay window around 70%.
• The optimized Eu-TDA method provided reliable cytotoxicity results, comparable to LDH detection.
• The assay demonstrated compatibility with natural killer (NK) cells and specific cytotoxic T lymphocyte (CTL) assays.
• The assay accurately detects target cell death based on hydrophilic complex levels.

Conclusions:

• An optimized medium component and protocol for cellular coincubation have been developed and validated for cytotoxicity assays.
• The validated method reliably evaluates the potency of engineered CD19 CAR-T cells, NK cells, and specific CTLs.
• This assay is broadly applicable for routine quality control and cell activity evaluation of co-suspended effector and target cells.