Inhibition of the factor VIIa–tissue factor complex by lactadherin or annexin V.

Recombinant tissue factor was reconstituted into vesicles of PS-PE-PC composition of 4:20:76 by detergent dialysis, with a tissue factor-PL ratio of 1:7500. The indicated concentrations of phospholipid, with included tissue factor, were incubated with the indicated concentrations of lactadherin or annexin V, 100 pM factor VIIa, 100 nM factor X, and 1.5 mM Ca⁺⁺ for 5 minutes prior to addition of EDTA and the chromogenic substrate S-2765. Lactadherin inhibited the function of the factor VIIa-tissue factor complex efficiently (A) while annexin V was less effective (B). Data displayed with tissue factor concentration of 1 nM (⋄) are representative of 3 experiments. Data from experiments with a tissue factor concentration of 0.2 nM (○) and 0.04 nM (▴) are representative of 2 experiments.