Comparison of targ-CD39, non–targ-CD39, and scFv_SCE5 alone in inhibition of platelet activation as assessed by P-selectin expression in flow cytometry. P-selectin expression was determined with a PE-labeled anti–P-selectin antibody. Bar graphs depict the median fluorescence intensity values of 3 independent experiments (mean ± standard error of the mean; ***P < .001). These assays were analyzed with 2-way repeated-measures analysis of variance with the Bonferroni posttest. Representative fluorescence histograms of P-selectin expression are shown in the same order and color as above.