Phenotypic, proteomic, and functional analyses of cytokine-induced memory-like NK cells show two distinct subsets...

Area of Science:

• Immunology
• Cell Biology
• Proteomics

Background:

• Natural Killer (NK) cells are crucial innate immune cells.
• NK cells can develop a memory-like phenotype upon cytokine stimulation (IL-12, IL-15, IL-18), termed cytokine-induced memory-like (CIML) NK cells.
• CIML NK cells possess enhanced cytotoxic potential and longevity, making them promising candidates for immunotherapy.

Purpose of the Study:

• To characterize distinct subsets of CIML NK cells based on CD16 expression.
• To compare the phenotype, degranulation capacity, and proteomic profiles of CD16- and CD16+ CIML NK cell subsets.
• To identify molecular differences that may explain functional variations between these subsets.

Main Methods:

• Isolation and overnight stimulation of primary NK cells with IL-12, IL-15, and IL-18 to induce CIML phenotype.
• Purification of CD16- and CD16+ CIML NK cell subsets using fluorescence-activated cell sorting (FACS).
• Analysis of cell phenotype, degranulation (CD107a/b expression), and high-throughput multiplexed quantitative proteomics.

Main Results:

• CD16- CIML NK cells displayed higher levels of activating receptors and Granulysin, with lower inhibitory receptor expression compared to CD16+ cells.
• The CD16- subset demonstrated superior degranulation capacity when co-incubated with target cells (K562 and melanoma).
• Proteomic profiling revealed 35 differentially expressed proteins, including Granzyme family proteins, NCAM1, and Fc receptors, between the two subsets.

Conclusions:

• This study provides a detailed molecular and functional characterization of CD16- and CD16+ CIML NK cell subsets.
• The observed differences in receptor expression and protein profiles underscore the functional heterogeneity within CIML NK cells.
• Findings may inform the development of more effective NK cell-based cancer immunotherapies.