Fig. 4.
Inhibitory effects of autoantibodies on FVIII proteolytic cleavage at Arg336 by APC in the absence of PL.
Autoantibody F(ab′)2 (0.5 μM) was added to 10 nM FVIII, which was bound to immobilized NMC-VIII/10 (0.2 μM). Then, 50 nM APC and 2.5 mM CaCl2 were added. At timed intervals, supernatants were removed and APC activity was stopped by adding 2 mM PMSF to the microtiter wells. FVIII cleavage at Arg336 was detected with peroxidase-conjugated mAb C5. Case 1, ○; case 2, ●; case 3, ■; type 1 autoantibody F(ab′)2, ▪; normal F(ab′)2, ▵.
