ISOLATION OF HUMAN-PLATELET MEMBRANE MICROPARTICLES FROM PLASMA AND SERUM

  • 1 January 1982
    • journal article
    • research article
    • Vol. 60  (4) , 834-840
Abstract
Methods were developed to isolate human platelet membrane fragments from plasma and serum. Rabbit antibody produced against the human platelet membrane glycoprotein complex, IIb/IIIa, was utilized in an immunoelectrophoretic assay to evlauate the amount of this antigen in various microparticle preparations. The serum concentration of platelet microparticles was more than 10-fold greater than that observed for plasma (65 vs. 4.4 .mu.g/ml, respectively). Ultrastructural evaluation of either plasma or serum-derived microparticles disclosed various membrane fragments and membrane-bound vesicles with occasional fragments of red blood cells, white blood cells and platelets. Microparticle preparations derived from isolated washed platelets after thrombin stimulation contained a heterogeneous array of membrane fragments, vesicles and granules, but no identifiable red cell, white cell or platelet fragments. Evidently, normal human plasma and serum contain platelet membrane fragments that are produced during cell activation. If a similar loss of platelet membranes occurs in vivo following reversible platelet activation, the resulting membrane modifications may be of importance in both the structural and functional changes that develop during platelet senescence.