Figure 5

<p>Increasing the killing frequency of fresh NK cells by cytokines and Rituximab. (A) Freshly isolated NK cells were cultured with IL-2 (10 or 100 U/ml) alone (A) or with IL-2 (100 U/ml) and IL-15 (10ng/ml), alone or in combination (B) IL-2 (100 U/ml) alone or in combination with IFN-α (1000U/ml) or poly I∶C (50 µg/ml) (C) for one week. Thereafter, stimulated NK cells were tested against 221 target cells using 4 hours Cr-⁵¹ release assays. Combining IFN-α or poly I∶C with only 10 U/ml IL-2 also showed no enhancement of cytotoxicity (data not shown). (D) 221 target cells were treated with Rituximab (10 µg/ml) and killing frequency of freshly isolated NK cells was assessed by 4 and 16 h ⁵¹Cr release assay and compared to untreated targets. Data are representative of three independent experiments using NK cells from different donors.