Phagocytosis in human platelets: localization of acid phosphatase positive phagosomes following latex uptake

Abstract

Incubation of human platelets in plasma containing a suspension of latex particles for 1 - 90 min resulted in progressive accumulation of particles in the open channel system, followed by localization of latex in electron opaque vacuoles. After 60 min, acid phsophatase was localized within latex containing vacuoles. The periodate alkaline bismuth reaction intensely stained external membranes and membranes of the open channel system. Membranes of latex containing organelles were not stained. Latex phagocytosis was independent of both anticoagulant choice and aspirin effects. These results indicate that the platelet can act as a true phagocyte, and it is suggested that the phagocytic process is chronologically similar to that reported for polymorphonuclear leukocytes.