Supplementary Material for: Differential Effector Function of Tissue-Specific Natural Killer Cells Against Lung Tumors

Introduction. Natural killer (NK) cells are innate lymphoid cells capable of directly killing target cells while modulating immune effector responses. Despite their multifunctional capacities, a limited understanding of their plasticity and heterogeneity has impeded progress in developing effective NK cell-based cancer therapies. In this study, we investigated NK cell tissue heterogeneity in relation to their phenotype and effector functions against lung tumors. Methods. Using hanging-drop tumor spheroid and subcutaneously established LL/2 lung tumor models, we examined NK cell receptor diversity and its correlation with tissue-specific cytotoxicity through multiparametric flow cytometry, fluorescence imaging, and cytotoxicity assays. Results. We identified distinct patterns of cell surface receptor expression on tissue-specific NK cells that are crucial for antitumor activity. Linear regression mathematical analyses further revealed significant positive correlations between activation-associated cell surface receptors and cytotoxic capacity in NK cells from tissues such as the liver and bone marrow. Conclusion. These findings underscore the differential effector capacities of NK cells from distinct tissues, even prior to exposure to LL/2 tumor cells. This highlights the significance of tissue-specific NK cell heterogeneity and its impact on their antitumor cytotoxicity. Recognizing these distinct tissue-specific receptor expression patterns will be instrumental in developing more efficacious NK cell-based cancer treatments.