Expression of CD94 by -differentiated NK cells correlates with the and acquisition of cytotoxic features.

The administration of -expanded Natural Killer (NK) cells in leukemia therapy is still challenging, in part due to the difficulty to generate in sufficient quantities fully mature and functional NK cells and Identification of surface markers indicative of NK maturation and functionality is therefore needed. Here, based on the analysis of surface receptors of -expanded NK cells, we identified CD94 as a surface marker correlating with high lytic potential against leukemic cell lines and immunological synapse formation. CD94-positive -expanded NK cells displayed higher expression of NKG2 receptors and the adhesion molecule LFA-1, as compared with their CD94-negative counterparts. We also tested the anti-leukemic capacity of -expanded NK cells against patient-derived acute myeloid leukemia cells. Although no anti-leukemic effect was detected, we noticed that only CD94-positive -expanded NK cells were detected in leukemic mice at the end of the 2-week treatment. Moreover, flow cytometry analysis showed a subpopulation harboring CD94 (NK) and CD34 (leukemic cells) double staining, indicative of conjugate formation. Therefore surface expression of CD94 on -differentiated NK cells emerged as an indicator of and killer cell functionality.