TIGIT and leukemia: As effector cells, we used CIML-NK cells and the NK-92 cell line for our functional experiments as this cell line displayed the highest TIGIT expression of all NK cell lines tested, but more importantly as this cell line displays a proven high cytotoxicity against human leukemic cell lines and primary leukemia as well as superior cytotoxic activity compared to HD-NK cells in vitro and in mice [35].