Enhanced Natural Killer Cell Proliferation by Stress-Induced Feeder Cells

Area of Science:

• Immunology
• Cell Biology
• Biotechnology

Background:

• Natural killer (NK) cells are crucial for innate immunity and allogeneic cell therapies.
• Their limited proliferative capacity and half-life hinder effective in vitro expansion for adoptive therapy.
• Current gene modification strategies for NK cell expansion face challenges like genetic instability and unintended gene expression.

Purpose of the Study:

• To develop a safer alternative to genetic modification for enhancing NK cell proliferation.
• To investigate the use of chemically stressed feeder cells to promote NK cell expansion.
• To establish a method for increasing NK cell numbers for therapeutic applications.

Main Methods:

• Feeder cells were treated with chemical-based extracellular stress, specifically hypoxia and cytochalasin D, to inhibit their proliferation.
• The expression of 4-1BBL on stressed feeder cells was analyzed.
• NK cells were co-cultured with stressed feeder cells, and their proliferation, CD56 expression, and cytokine release were assessed.
• The process was validated under dynamic conditions simulating bioreactor environments.

Main Results:

• Chemical stress inhibited feeder cell proliferation, enhancing their efficiency as feeder cells.
• Stressed feeder cells showed upregulated 4-1BBL expression, promoting NK cell proliferation via 4-1BB interaction.
• Co-culture with stressed feeder cells led to increased CD56 expression on NK cells, specifically CD56bright, enhancing cytokine release and proliferation.
• Feeder cell-mediated NK cell expansion was effective under dynamic shear stress conditions.

Conclusions:

• Chemically stressed feeder cells provide a safe and effective non-genetic method to enhance NK cell proliferation.
• This approach overcomes the limitations of genetic modification for NK cell expansion in vitro.
• The method is applicable in dynamic culture systems, paving the way for scalable NK cell-based therapies.