The Development of Platelet Factor 3 Activity by Latex Particles—An Interaction with Plasma

Platelet factor 3 activity of polystyrene latex particles was found to be absent when the particles were tested without prior incubation with plasma. Following such incubation, the particles developed considerable but suboptimal activity. An interaction between the particles and some plasma component(s) during the incubation period which gives rise to a labile type of activity has been postulated.