Figure 4.

Defective [¹²⁵I]UdR release exhibited by DPPI−/− CTL and LAK cells. Standard cytotoxicity assays of wild-type (□), DPPI−/− (◊), granzyme A−/− × B−/− (○), and perforin−/− (▵) LAK cells tested against YAC-1 target cells at increasing effector/target (E:T) ratios (Left); CTL were tested against TA3 and P815 target cells (Center and Right). Release of [¹²⁵I]UdR is measured after 2 (Upper) and 6 (Lower) hr. The results are represented as mean ± SEM of duplicate samples. This experiment was repeated three times with similar results. Note that DPPI−/− LAK and CTL have an early defect in [¹²⁵I]UdR release that is due to the loss of active granzyme B, and a persistent defect at 6 hr that is caused by the loss of active granzyme A.