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Activation of human platelets by exposure to a monoclonal antibody, PM6/248, to glycoprotein IIb‐IIIa
Author(s) -
Hornby E. J.,
Brown S.,
Wilkinson J. M.,
Mattock C.,
Authi K. S.
Publication year - 1991
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1111/j.1365-2141.1991.tb04533.x
Subject(s) - platelet , monoclonal antibody , chemistry , platelet activation , incubation , antibody , glycoprotein , platelet membrane glycoprotein , thromboxane , microbiology and biotechnology , membrane glycoproteins , platelet rich plasma , intracellular , biochemistry , immunology , biology
Summary Monoclonal antibody PM6/248, which recognizes the GPIIb‐IIIa complex on human platelets, causes platelet aggregation in platelet‐rich plasma or in gel‐filtered platelet suspensions. Aggregation follows a concentration‐dependent lag phase and reaches a maximum at 8 μg/ml. High concentrations of antibody (< 30 μg/ml) produce complete inhibition of the aggregation response. Aggregation is accompanied by serotonin secretion and thromboxane A 2 synthesis, neither of which are inhibited by high concentrations of antibody, and by the mobilization of intracellular Ca 2+ . The F(ab') 2 fragment of PM6/248 does not cause platelet activation and pre‐incubation of platelets with this fragment inhibits all platelet responses stimulated by the whole antibody. Pre‐incubation with the F(ab') 2 fragment of the anti‐FcγRII Mab, IV. 3, also inhibits all responses to PM6/248. These data indicate that platelet activation stimulated by PM6/248 is caused by cross‐linking of GPIIb‐IIIa to the FcγRII which stimulates signal transduction across the plasma membrane through a conformational change in the FcγRII.