Profile and kinetics of NK-cell secretion upon interaction with K562 cells. (A) Resting NK cells were incubated alone or with K562 cells for 6 hours at 37°C. Supernatants were harvested, and the concentrations of indicated cytokines and chemokines were determined by a multiplex immunoassay. Values represent mean ± SD of 8 different donors. (B) NK cells were mixed with K562 cells and incubated at 37°C. Supernatants were harvested at different time points, as indicated, and the concentrations of IFN-γ, TNF-α, MIP-1β, MIP-1β, and RANTES were determined by a multiplex immunoassay. Values represent mean ± SD of 5 different donors.