Research Paper Volume 17, Issue 3 pp 798—821

Figure 1. Decreased levels of surface receptors, cytotoxicity, and IFN-γ secretions in NK cells from older donors. PBMCs-derived NK cells from 21-25 years and 75-85 years donors were used to determine the surface expression levels of Nkp30, Nkp44, Nkp46, KIR2, KIR3, CD94, and NKG2D using flow cytometric analysis (one of three representative experiments is shown in the figure) (A). NK cells were left untreated or were treated with IL-2 (1000 U/ml) or with a combination of IL-2 (1000 U/ml) and anti-CD16 mAbs (3 μg/ml) for 18 hours before they were used as effectors in standard 4-hour ⁵¹Cr release assay against OSCSCs (n=3, B). The lytic units 30/10⁶ cells were determined using the inverse number of NK cells required to lyse 30% of OSCSCs X 100. NK cells left untreated ot treated with IL-2 (1000 U/ml) or with a combination of IL-2 (1000 U/ml) and anti-CD16 mAbs (3 μg/ml) for 18 hours before the supernatants were harvested to determine IFN-γ secretion using single ELISA (n=3, C). *(p-value 0.01-0.05).