Cytotoxic activity of expanded NK cells against non-tumor cells.

<p>Selective cytotoxicity of expanded NK cells against mixed targets of normal PBMCs and K562 cells was analyzed by flow cytometric cytotoxicity assay as described in the <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0053611#s2" target="_blank">Materials and Methods</a>. K562 tumor target cells were labeled with calcein-AM, and either allogeneic (A) or autologous (B) PBMC target cells were labeled with anti-HLA-class I. The expanded NK cells, the labeled K562 target cells, and the labeled PBMC target cells were cocultured at the ratio of 3∶1∶1 for 2 h. Dead cells were stained with 7-AAD, and the percent specific lysis was calculated. Cytotoxicity against PBMCs (left of each panel) and K562 cells (right of each panel) is presented separately. The assay was performed in duplicated. Each bar graph represents mean+SD.