Phospho-epitope profiling in human CD56⁺ NK cells. (A) Kinetic analysis of phosphoprotein after stimulation with anti–LFA-1 cross-linking in human CD56⁺ NK cells. Peripheral blood was cross-linked for LFA-1 antibody (mAb clone 27) and stained in 4-color combinations of CD56-PE-Cy5 and 3 phosphospecific antibodies coupled to Alexa 488, Alexa 568, Alexa 647, Alexa 660, or PE. Ratios of the fluorescent intensities (geometric mean) were calculated relative to unstimulated cells. All values were derived from CD56⁺ and CD56^– gated populations and computed using Cluster and Treeview software programs.