Fig 1: Serum EVs contain high levels of platelet proteins in human blood.(A) Western blot analysis of the sEV fractions derived from plasma and serum of 5 individuals, using antibodies against EV markers and platelet-specific proteins. Equal amounts of proteins were loaded onto each lane and analyzed. (B) Bar graph showing relative protein levels of CD63 that were calculated from the band intensity of the Western blot image in (A). (C-D) Bar graphs showing the levels of the EV marker CD9 (C), and platelet-specific markers GPIIb, GPIIIa and PF4 (D), relative to that of CD63. Whereas the level of CD9 was comparable between the sEV fractions from plasma and serum, all the platelet markers showed a clear tendency of increased levels in serum EVs. (E) NTA results showing the numbers (left) and median diameters (right) of the particles in the sEV fractions derived from human plasma and serum. (F) Comparison of the sEV fractions derived from mouse and human blood by Western blot analysis using antibodies against EV markers and lipoprotein ApoA1. The sEV fractions isolated from human blood contain very low levels of the EV markers CD63 and Hsc70, but a high level of ApoA1, implying a large difference in particle population between human and mouse blood. Data are shown as the average ± SEM. Student t-test. n.s., not significant.