To further to testify that SZ34 is a conformational mAb against VWF, a western blot in combination with ELISA based on polystyrene microspheres was performed to compare the binding activities of SZ34 to native pVWF and denatured pVWF. Compared with native pVWF, the binding activity of SZ34 to heated pVWF or pVWF treated with 1.5 M guanidine-HCl was significantly reduced (Figure 6 ), further confirming that SZ34 is a conformation-sensitive mAb to VWF.