Figure 3: Cytotoxicity of effector CTL against MCF-7 cells. Target MCF- 7 cells were seeded at 5 104 cells per well in 48-well tissue culture plates, and then effector CTL were added at CTL:MCF-7 ratios ranging from 1:1 to 8:1. A ratio of 0:1 indicates growth of MCF-7 cells to which effector CTL were not added. (?) - MCF-7 cells incubated with CTL that had been stimulated with trypsin digest-loaded DCs. () MCF-7 cells incubated with CTL that had been stimulated with lysate-loaded DCs. (?) - MCF-7 cells incubated with CTL that had been stimulated with unloaded DCs. (?) MCF-7 cells grown either alone, or with unstimulated PBMC. Points represent the mean value of 3 identical measurements. As an example, the standard deviation for the 4:1 ratio is shown (similar values for standard deviation were obtained using other CTL:MCF-7 ratios).