Figure 4.

IL-2 restores the killing ability of inactivated NK cells. IL-2 activated NK cells were incubated with or without 221 targets for 16 hours at an E∶T ratio of 0.2∶1. Thereafter, NK cells were re-isolated by CD56 positive selection using MACS columns and cultured in the presence of IL-2 (100 U/ml). Killing assays against 221 target cells were performed on day 1 (A) and 2 (B) after isolation. Data from three independent donors show that NK cells regain their lost cytotoxic ability on day 2 in response to IL-2 treatment.