MP-associated TF PCA is recovered in the pellet of ultracentrifuged platelet-free plasma following LPS exposure in vivo Platelet-free plasma from 2 volunteers, obtained 3 to 4 hours after LPS exposure, was subjected to high-speed ultracentrifugation. The resuspended pellet and supernatant fractions were then independently assayed for MP-associated TF PCA, as described in “Materials and methods.” An inhibitory polyclonal antibody to TF (with or without poly TF Ab) was included in some wells.