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. 2011 Oct 6;29(43):7435–7443. doi: 10.1016/j.vaccine.2011.07.062

Fig. 3.

Fig. 3

Inhibition of factor I cofactor activity of VCP for C3b and C4b by anti-VCP monoclonal antibodies. (A) Inhibition of C3b cofactor activity. C3b (3 μg) was incubated with VCP (0.5 μg), factor H (1 μg; fH; control) or VCP (0.5 μg) pre-incubated with each of the mAbs (where indicated) and factor I (100 ng) at 37 °C for 2 h. The reactions were stopped by adding SDS-PAGE sample buffer containing DTT and ran on SDS-PAGE gels. (B) Inhibition of C4b cofactor activity. C4b (3 μg) was incubated with VCP (0.5 μg), soluble complement receptor 1 (1 μg; sCR1; control), or VCP (0.5 μg) pre-incubated with each of the mAbs (where indicated) and factor I (100 ng) at 37 °C for 2 h. The reactions were stopped by adding SDS-PAGE sample buffer containing DTT and ran on SDS-PAGE gels. The gels were stained with Coomassie blue to visualize inhibition of α′-chain cleavage, which indicates inhibition of C3b or C4b cofactor activity.