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. 2007 Mar 28;2(3):e326. doi: 10.1371/journal.pone.0000326

Figure 3.

Figure 3

Serial killing of tumor cells by NK cells is mediated by Perforin and Granzyme B. (A) IL-2 activated NK cells, alone (−221) or together with 221 target cells (+221) were incubated for a period of 16 hours at an E∶T ratio of 0.2∶1 and then stained intracellularly for Perforin and Granzyme B content. NK cells were identified by gating on CD56 positive cells. Fold expression shown here represents the ratio of MFI of Perforin/Granzyme B and respective isotypes. Figure is representative of multiple donors. (B) IL-2 activated NK cells were incubated alone or in combination with 221 targets at an E∶T ratio of 0.2∶1. After 16 hours, cells were harvested and stained for CD56 expression (NK cells) and annexinV (apoptotic cells). NK and 221 cells alone were used as controls. Forward and sideward scatter gating was used to gate on free NK cells, free 221 cells or conjugates. Figure is representative of multiple donors.