Characteristics of NK cells activation following IL-12, IL-15, IL-18 cytokines stimulation for preclinical purposes

Adoptive cell therapy is a promising strategy in cancer treatment, among which NK cell therapies represent an encouraging approach. Freshly isolated NK cells exhibit low cytolytic activity. Therefore, efficient activation of NK cells is essential to enhance their anti-cancer properties. The aim of this study was to compare ex vivo NK cells activation with commonly used cytokines, including IL-2, IL-12, IL-15, IL-18, or STING agonist, and to determine the most effective activation method. Our results indicate higher viability and expression of activating receptors and granzyme B in IL-15-treated NK cells. The addition of IL-12 to IL-15 augmented the production of IFN-γ and CCL3 in NK cells. However, incubation of NK cells with a cocktail of IL-12, IL-15, and IL-18 cytokines generated massive production of pro-inflammatory cytokines and a significant increase in activation marker CD69. We have also observed reduced viability of NK cells after incubation with STING agonist. NK cells activated with IL-12/IL-15, and IL-12/IL-15/IL-18 co-cultured with MHC^- tumor cells, and in each cytokine combination with MHC⁺ tumor cells caused proliferation inhibition and lysis of tumor cells. Activation of NK cells, particularly with the combination of IL-12/IL-15/IL-18 cytokines, shows potential clinical relevance in adoptive cell therapy.