Cell-derived vesicles from saliva initiate TF/factor VII–mediated coagulation activation. Human plasma, depleted from vesicles by ultracentrifugation, was incubated with microparticles (A,C) or exosomes (B,D) isolated from autologous saliva (A-B) or plasma (C-D), without (●) or with antifactor XII (○) or antifactor VII (▵). Coagulation/clot formation was initiated by addition of calcium chloride (t = 0) and monitored for 1 hour. The graphs shown were obtained within one single experiment and are representative of 6 other independent experiments.