Anti-FVIIa MoAb 12C7 mimics FVIIa T99Y functional properties. (A) Representative immunoblot showing the effect of anti-FVIIa MoAbs 3G12 and 12C7 (20 µg/mL) on TF-dependent FVIIIa generation in reactions including 50 pM rTF, 200 pM FVIIa, 135 nM FX, 3.5 nM FVIII, 3 nM FV, and 200 nM lepirudin incubated for 120 s at 37°C (left). Quantification of the data on the left (n = 3; min-to-max floating bars, line at the mean) (right); differences were evaluated by Welch-corrected 2-tailed t test. (B) Anti-FVIIa MoAb 12C7, but not 3G12, preserves FVIIIa-dependent FXa generation by 10 nM FIXa (left; n = 3), but not 90 nM FIX (right; n = 3-5) in reactions containing 50 pM rTF, 200 pM FVIIa, 700 pM FVIII, 3 nM FV, 135 nM FX, 10 nM TFPIα, 200 nM lepirudin, and 2.5 mM CaCl₂ incubated for 180 or 360 s, respectively, at 37°C. Anti-FVIIa MoAbs or control mouse IgG were added at 20 µg/mL. Results (min-to-max floating bars, line at the mean) were analyzed by ANOVA/Tukey tests. (C) Representative thrombograms (n = 2) showing the effect of anti-FVIIa MoAbs 3G12 and 12C7 (20 µg/mL) on 1.2 pM rTF-induced TG in normal PRP with CTI (30 µg/mL) and without (left) or with (right) addition of anti-FXI MoAb O1A6 (20 µg/mL) blocking FIX activation by FXIa. **P < .01. ***P < .001.