Fig. 5. Additive cytotoxicity and estimation of damage recovery half-life.

a Time-lapse sequence and intensity plot of multiple Ca²⁺ events followed by target cell apoptosis. Green fluorescence, OT1 CTL (dsRed); Fire LUT, Ca²⁺ intensity (GCaMP6s). Cross, target cell death; Scale bar, 20 µm. Image sequence shows a representative example from 124 perforin events preceding N = 63 B16F10/OVA apoptosis events, pooled from 5 independent experiments. b Survival probability of B16F10/OVA cells having received increasing numbers of Ca²⁺ events. c Simulation of stochastic apoptosis induction by permutation of waiting times between Ca²⁺ events, survival, and lag times until apoptosis. p-Values in c, d, two-sided log rank test comparing all groups. d Estimation of damage recovery half-life in B16F10/OVA after one single Ca²⁺ event by a statistical model that assumes additive killing (see “Methods”). Point and error bar: damage half-life that is most consistent with the data and at 95% confidence interval. Data in b–d represent 124 perforin events related to N = 63 B16F10/OVA apoptosis events, pooled from 5 independent experiments. e Killing efficacy of B16F10/OVA cells and percentage of preceding single or multiple interacting CTL in dependence of ET ratio. Left panel, means and SD from N = 2 independent experiments; right panel, 110 contacts from N = 4 independent experiments per ET ratio. Source data are provided as a Source Data file.