• natural killer cells;
  • cytotoxicity;
  • mathematical model;
  • cytometry


Natural killer (NK) cells are capable of lysing their target cells with the help of perforin. The application of these cells for immunotherapy requires the estimation of their potency for the purpose of validation and batch-to-batch comparison. Cytotoxicity measurements have been carried out at only a few effector target ratios, therefore, allowing only semiquantitative assessment at best. By using a novel approach of varying the effector target ratio continuously and careful analysis of the experimental data after the reactions, we have achieved a precision necessary for constructing a mathematical model of cytotoxic reaction. Curve-fitting to experimental data indicates that NK cell cytotoxicity follows the law of mass action and fits the model of a single ligand–receptor interaction. The method allows to use the value of half-maximal lysis to describe the potency of cytotoxic NK cells numerically. © 2013 International Society for Advancement of Cytometry