Microchip Screening Platform for Single Cell Assessment of NK Cell Cytotoxicity

Area of Science:

• Immunology
• Cell Biology
• Biotechnology

Background:

• Natural killer (NK) cells are crucial for innate immunity and cancer surveillance.
• Assessing individual NK cell cytotoxic potential is challenging in large populations.
• Understanding NK cell heterogeneity is vital for immunotherapy and transplantation.

Purpose of the Study:

• To develop and validate a high-throughput screening platform for evaluating individual NK cell cytotoxicity.
• To characterize the cytotoxic potential and heterogeneity of primary human NK cells.
• To explore the application of this platform in clinical settings.

Main Methods:

• A silicon-glass microchip with 32,400 microwells was used to isolate individual NK cells with target cells.
• Automated fluorescence screening and image analysis quantified NK and target cell viability.
• Time-lapse live-cell imaging assessed serial killing by individual NK cells.

Main Results:

• Most resting NK cells (≈75%) showed minimal cytotoxicity against K562 leukemia cells.
• A subset of NK cells demonstrated the ability to kill multiple target cells (≥3) within 12 hours.
• A small fraction of highly cytotoxic NK cells accounted for a significant portion of overall tumor cell killing.
• Cytotoxic potential varied among donors, highlighting NK cell heterogeneity.

Conclusions:

• The developed microchip platform enables precise enumeration and characterization of cytotoxic cells, including NK and T cells.
• This technology can identify highly cytotoxic NK cell subsets for therapeutic applications.
• Potential clinical applications include donor selection for stem cell transplantation and generating cells for adoptive immunotherapy.