Eosinophils autonomously initiate thrombin generation. (A and B) Calibrated thrombin generation curve of in vitro–generated mouse eosinophils (mEOS; A) or human eosinophils (huEOS; B) after stimulation with ADP and/or collagen. Bar graphs show endogenous thrombin potential (ETP; nM*min) and peak of thrombin generation (peak; nM). (C) Calibrated FXa generation curve of mouse eosinophils. AU, arbitrary units. (D) Plasma clotting time experiments with in vitro–generated mouse eosinophils (Eos) stimulated with ADP or collagen. Bar graphs display calculated clotting index. The black bar shows plasma with ADP alone. (E, left) Quantitative RT-PCR analysis of TF mRNA (F3) expression in mouse monocytes (monos), neutrophils (PMN), eosinophils (eos), and platelets (plts); expression of the gene of interest was normalized to Atcb expression. (Right) Western blot analysis of TF protein (47 kD) expression in sorted mouse leukocytes. (F) Flow cytometry analysis of the exposure of TF on the surface of resting or ADP-stimulated mouse eosinophils. Histograms show representative flow cytometric stainings, and bar graphs show mean geometric fluorescence intensities (geom. MFI). (G, left) Calibrated thrombin generation assay with ADP-stimulated mouse eosinophils in the presence of blocking anti-TF antibody or isotope control. (Right) Bar graphs show endogenous thrombin potential (ETP; nM*min) and peak of thrombin generation (peak; nM). Data are representative of at least three independent experiments. Error bars represent SEM. *, P < 0.05; **, P < 0.01; ***, P < 0.001; ****, P < 0.0001; Student’s t test.