Binding and in vivo effect of MBB2ΔCH2. (A) Human or mouse β2GPI (10 μg/mL) immobilized on γ-irradiated polystyrene plates were incubated with different concentrations of either MBB2ΔCH2 or control MB, and the bound scFv-Fc was measured using ELISA. (B) Deposition of C1q and C4 to bound MBB2ΔCH2 and MBB2 was evaluated as indicated in the legend to Figure 3. (C) Thrombus formation and (D) vessel occlusion monitored by intravital microscopy at different time intervals in LPS-primed normal rats receiving either MBB2ΔCH2 or MBB2. Percentages of (E) fetal loss and (F) fetal weight in pregnant mice treated with either MBB2ΔCH2 or MBB2. The procoagulant and proabortive effects of MBB2 and MBB2ΔCH2 were evaluated and analyzed as reported in Figure 2. The data of vessels occlusion and fetal weight are expressed as mean ± SD; percentages of fetal loss are expressed as median ± interquartile range presented as box plots. *P < .05, **P < .01.