Highly Efficient Elimination of Colorectal Tumor-Initiating Cells by an EpCAM/CD3-Bispecific Antibody Engaging Human T Cells
Figure 2
Eradication of primary colorectal tumor-initiating cells (TICs) by MT110-engaged T cells.
(A) Photographs of crystal violet-stained colonies growing from TICs treated in the presence of T cells with the indicated concentrations of MT110, control BiTE antibodies at 200 ng/ml, or T cells alone. Unstimulated PBMCs were used as source of T cells at a PBMC to TIC ratio of 1∶1. (B) MT110 dose response of redirected lysis. Number of CFUs from TICs per cm2 are shown. Bar graphs are mean values of colony numbers from triplicate determination +/− SD observed after 11 days. Unstimulated PBMCs or CD8+ cells were used as effectors as indicated at an E:T ratio of 10∶1. (C) Effect of E:T ratio and T cell donor on redirected lysis. Number of CFUs per cm2 of TIC cells treated with 10 ng/ml MT110 or a CD3-monospecific BiTE control antibody at the indicated E:T ratios and incubation times are shown. Bar graphs are mean values of colony numbers from triplicate determination +/− SD as observed after 17 days. Unstimulated PBMCs from two healthy blood donors were used as effector cells. (D) Time dependence of redirected lysis. Number of CFUs per cm2 from TICs treated with 10 ng/ml MT110 or a CD3-monospecific BiTE control antibody at a PBMC to TIC ratio of 1∶1 are shown. Bar graphs are mean values from a triplicate determination +/− SD observed after 15 days.