Correlation between speed and strength of the NK response. (A) Calcein intensity profiles for 293T cells treated with melittin. (B-C) Conjugation (B) and attachment (C) times for nonlytic interactions and lytic interactions resulting in slow and fast target cell death. (D) Time to lytic hit for slow or fast target cell death. (E) Percentage of kills over number of lytic hits. Inset: example of a calcein decay showing 2 consecutive hits. (F) Distribution of time gaps between lytic hits. Error bars indicate SE. n.s. indicates P > .05. Values above bars in panels E and F indicate n.