Figure 2.

TR1-IgMs induce tumor cell killing by apoptotic signaling. (A) Cell viability assay. Colo205 cells were incubated with the indicated antibodies for 24 h, and cell viability was measured. (B) Measurement of activated caspases. The cells were incubated with the indicated concentrations of TR1-IgM(J+)s or control-IgM(J+). Activated caspase-8, and -3/7 were measured after 3 and 6 h of culture, respectively. (C) Caspase-dependent cell death in Colo205 cells. The cells were incubated with or without the indicated concentrations of z-VAD-fmk for 4 h. Then, the cells were cultured with TR1-IgMs or control-IgM for 24 h. After cell culture, the cell viability was determined. The data are shown as the mean ± SD of triplicate cultures. *p < 0.05 by Student’s t-test.