Figure 2.

Nine timepoints during the killing of a NP68-presenting LD^b target cell by two F5 cells (CTL) during a timelapse video recording made in the presence of 10 nM P68. The times shown (hh:mm:ss) in the upper part of each image are relative to the moment of first contact between the CTLs and the target cell, whereas those in the lower part are relative to the first cytoplasmic contraction of the target cell at the onset of zeiotic death. During the long (almost 3 hr) browse that preceded death, the target cell appeared normal and healthy, with lamellipodial ruffling, and the CTLs moved actively over its surface. The target cell then contracted, rounded up, and exhibited zeiotic blebbing, actively for the first 15 min, and then with decreasing vigor for a further 20 min, by which time the target cell corpse had completely detached from the substratum and exhibited no further activity. The field of view is ≈40 μm wide.