Figure 4
mbIL-21 signaling promotes increased metabolic activity in NKF-NK cells but does not affect cytotoxicity. (A) NKF cells lead to enhanced NK cell proliferation as compared to OCI-AML3 cells at a 5:1 feeder-to-NK ratio as measured by cell counts after 3 weeks of expansion. The proliferation marker, Ki67, expression is higher in NKF-NK cells as compared to IL-2-NK and OCI-NK cells as assessed by flow cytometry, n = 4. (B) NKF-NK cells exhibit increased pSTAT3 and c-myc levels compared to IL-2-NK and OCI-NK as measured by flow cytometry, n = 4. (C) OCR and ECAR measurements of IL-2-NK, OCI-NK, and NKF-NK cells at baseline and after the addition of oligo (1 µM) and FCCP (0.25 µM). Average OCR (D) and ECAR (E) measurements of IL-2-NK, OCI-NK, NKF-NK cells at baseline and stressed conditions. (F) OCR/ECAR ratio of IL-2-NK, OCI-NK and NKF-NK cells. (G) ECAR vs OCR plot illustrating the energetic state of the indicated NK cells, n = 4. (H) NKF-NK cells demonstrate similar cytotoxic activity to OCI-NK cells as were measured by the 4-hr cytotoxicity assay using hematologic malignancy or solid tumor cell lines at a 1:1 NK:Target cell ratio, n = 4. NK cells were expanded 2–3 weeks for these experiments. Data represents mean +/− SEM. *p < 0.05, **p < 0.01, ***p < 0.001.
