Effector cells were coincubated
with Cr51 (150 ,uCi for 5 x 106) labeled target cells
for 4 hr at 37°C in different effector and target cell ratios.
Parental MCA-26 cells were used as target cells for the CTL
assay. After incubation, the radioactivity of 100 ,lI of the
supernatant was counted in a gamma counter. The percentage
of specific cytolysis was calculated as (experimental release -
spontaneous release)/(maximum release - spontaneous release)
x 100.