1H5 inhibits Notch cleavage. Sandwich ELISA was used to measure the levels of total (A) and cleaved (B) Notch1 in COLO205 cells upon treatment with 1H5. The data represent mean of triplicate experiments, and the bar plots show the effect of treatment with 1H5 relative to untreated control, mean ± SEM. Comparison of notch levels between treated and untreated groups was performed using independent t test. Total Notch1 levels did not significantly differ between the two groups (A), p = 0.162. On the other hand, the mAb-treated group showed significant decrease of the cleaved Notch1 levels when compared with the untreated control (B), p < 0.001.