Figure 2: CTL mediated lysis of MCF-7 cells during cytotoxicity assay. 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 ratio 4:1. On following (a-d) or 3rd (a-d) day, target cells were carefully washed with HBSS and photographed on an inverted phase contrast microscope (scale bar: 50 m). (a, a) MCF-7 cells grown alone. (b, b) MCF-7 cells incubated with CTL that had been stimulated with unloaded DC. (c, c) MCF-7 cells incubated with CTL that had been stimulated with lysate-loaded DC. (d, d) MCF-7 cells incubated with CTL that had been stimulated with trypsin digest-loaded DC.