Figure 8. CD16 triggering in primary NK cells inhibited granzyme B.

Purified NK cells were treated as described in Figure 1A and after an overnight treatment, the supernatants were removed from the co-cultures and the levels of granzyme B secretions were determined using specific ELISA. *The difference between IL-2 and IL-2+anti-CD16mAb treated NK cells is significant at a P < 0.05 A. Purified NK cells were treated as described in Figure 1A and after 12–18 hours of incubation, NK cells were fixed, permeabilized and stained with PE-conjugated anti-human CD56 and FITC-conjugated anti-human granzyme B. The intracellular expression of granzyme B was assessed with flow cytometric analysis. Isotype control antibody was used as control. Mean Fluoresce Intensities (MFI) for each sample were determined and fold increase or decrease based on untreated NK cells were assessed B. Primary NK cells and NK92 cells (1×10⁶ cells) were left untreated or treated with anti-CD16mAb (3 μg/ml), IL-2 (1000 units/ml) or a combination of IL-2 (1000 units/ml) and anti-CD16mAb (3 μg/ml) for 24 hours before the cells were fixed, permeabilized and stained as described in the Materials and Methods section. The intracellular expression of granzyme B was analyzed by flow cytometry and Mean Fluoresce Intensities (MFI) for each sample were determined and fold increase or decrease based on untreated NK cells or untreated NK92 cells were assessed C. Overlay of isotype, IL-2 treated NK cells and IL-2+anti-CD16mAb treated NK cell histograms were analyzed by FlowJo software D.