Generation of anti-MDTCS mAbs. (A) Binding of newly developed mAbs to immobilized MDTCS_(V5-6xHis) was investigated by ELISA. Bound anti-MDTCS mAbs were detected using HRP-labeled goat anti-mouse antibodies. Data (mean ± SD; n = 3) were expressed relative to the binding of the anti-MP domain mAb 3H9 to MDTCS_(V5-6xHis), which was set as 1 (data not shown). (B) The influence of anti-Cys/Spacer domain mAbs on plasma ADAMTS13 activity was studied using the FRETS-VWF73 assay (mean ± SD; n = 3). Differences between ADAMTS13 activity were statistically analyzed using analysis of variance with multiple comparison test. *P < .01. Activating and inhibitory mAbs are shown as purple and light green bars, respectively. Nonactivating/noninhibitory mAbs are shown as blue bars.