Results of immunocytochemistry performed on platelets.

(A) The platelets were isolated from circulating blood and deposited on collagen-coated slides. Immunocytochemistry was performed to detect TF. When stained, the platelets did not test positive for TF. Hemotoxylin was used for counter staining. (B) THP-1 cells induced to produce TF and also TF⁺ microparticles by treatment with TNF-α were perfused over a platelet carpet on a collagen-coated glass slide that was mounted in a parallel plate flow chamber.14The induced THP-1 cells were perfused over the platelets at 500s⁻¹. Note that platelets turned a brown color, indicating TF⁺, after exposure to TF containing THP-1 cells (original magnification × 200).