Adaptive NK Cells Resist Regulatory T-cell Suppression Driven by IL37

Area of Science:

• Immunology
• Cancer Biology
• Cellular Immunology

Background:

• Natural killer (NK) cells combat cancer and viral infections.
• Tumor microenvironments contain regulatory T cells (Tregs) that suppress immune responses, correlating with poor cancer prognosis.
• Intratumoral Tregs inhibit NK cell anti-tumor functions.

Purpose of the Study:

• To investigate the differential susceptibility of canonical and adaptive NK cells to Treg-mediated suppression.
• To elucidate the mechanisms underlying Treg suppression of NK cells.
• To identify potential therapeutic targets for enhancing NK cell-based cancer immunotherapy.

Main Methods:

• Comparative analysis of canonical and adaptive NK cell responses to Tregs.
• Assessment of NK cell proliferation, cytokine production (IFNγ), degranulation, and cytotoxicity.
• Evaluation of inhibitory receptor (TIM3, PD-1, IL1R8) and ligand (IL37) expression and function.
• Inhibition studies using blocking antibodies against PD-1, IL1R8, and IL37.

Main Results:

• Tregs suppressed canonical NK cells but not adaptive NK cells in terms of proliferation, IFNγ production, degranulation, and cytotoxicity.
• Treg suppression involved downregulation of TIM3 and upregulation of PD-1 and IL1R8 on canonical NK cells.
• Treg-produced IL37 contributed to the suppression of canonical NK cells via IL1R8.
• Blocking PD-1, IL1R8, or IL37 reversed Treg-mediated suppression of canonical NK cells.

Conclusions:

• Adaptive NK cells are inherently resistant to Treg-mediated suppression.
• Tregs employ mechanisms involving TIM3, PD-1, IL1R8, and IL37 to inhibit canonical NK cell function.
• Enhancing adaptive NK cells or blocking Treg suppression pathways offers promising strategies for improving NK cell cancer immunotherapy.