Role of inhibitory NK receptor/HLA-class I interactions in the induction of CCR7 expression. (A-B) Freshly isolated NK cells were purified, cultured for 1 hour with the indicated cell lines either in the presence or in the absence of anti–HLA-class I monoclonal antibodies (mAbs), and analyzed by 2-color immunofluorescence for the expression of CCR7 in combination with CD56 (A). Fresh NK cells were also cocultured for 1 hour with the HLA I–negative 221 cell line in the presence or in the absence of antibodies specific for the indicated surface molecules and then analyzed for CCR7 expression (B). In both panels A and B, the values reported in the top right corners indicate the percentage of CD56⁺ CCR7⁺ NK cells. The experiment shown is representative of 8 independent experiments performed using different donors.