Fig. 4.

Inhibition of classical pathway decay-accelerating activity of VCP by anti-VCP monoclonal antibodies. The classical pathway (CP) C3-convertase was formed on sheep erythrocytes and allowed to decay in the presence of VCP (0.2 μM) or VCP (0.2 μM) and antibody (1 μM). The remaining C3-convertase activity was detected by adding EDTA-sera (a source of C3-C9). The percentage of CP C3-convertase activity was normalized by considering the percentage of lysis in the absence of VCP as 100%. The dotted line was used as a cut off for determining the inhibition of VCP mediated decay of C3-convertase by mAb. NA indicates controls where no antibody was added.