Intracellular accumulation of IFN-γ, IL-5, TNF-α, and GM-CSF in CD56⁺ and CD56⁻ NK cells from cultures of Lin⁻ cells to determine the sequence with which the ability to produce type 1 and type 2 cytokines is acquired during differentiation.

Cells from primary cultures of Lin⁻ cells with Sl/Sl⁴hSCF²²⁰ feeder cells and IL-2 (left panels) or IL-15 (right panels) were stimulated as in Figure 3. Intracellular cytokines and surface phenotype were analyzed simultaneously (3-color immunofluorescence) on gated CD161⁺cells within purified CD3⁻ cells using FITC-, PE-, or biotin-labeled mAbs to the indicated molecules and streptavidin-R670. Quadrants were set to distinguish CD56⁺ and CD56⁻ cells. Percent positive cells is indicated in each quadrant. Experiment representative of 4 performed with similar results.