Thromb Haemost 1985; 54(02): 397-401
DOI: 10.1055/s-0038-1657748
Original Article
Schattauer GmbH Stuttgart

Interaction of β2-Glycoprotein-I with Human Blood Platelets: Influence Upon the ADP-Induced Aggregation

Johannes Nimpf
*   The Physiological Institute, University of Graz, Austria
,
Helmut Wurm
*   The Physiological Institute, University of Graz, Austria
,
Gerhard M Kostner
**   The Institute of Medical Biochemistry, University of Graz, Austria
› Author Affiliations
Further Information

Publication History

Received 11 January 1985

Accepted 22 April 1985

Publication Date:
18 July 2018 (online)

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Summary

The interaction of β2-glycoprotein-I (β2-G-I), a plasma constituent of unknown function, with blood platelets was studied. The following results were obtained: 1) β2-G-I binds to washed human platelets isolated by centrifugation (WP) at one kind of specific, saturable binding sites. The dissociation constant was found to be approx. 1 × 10−6M.

2) In the presence of physiological concentrations of Ca++ (2.5 mM), this specific binding is markedly reduced. Unspecific binding of β2-G-I to platelets, however, is not influenced by Ca++.

3) Platelets prepared by gel filtration (GFP), differing in their in vitro aggregability from WP, exhibit no specific binding of β2-G-I. Binding to GFP is also not induced by activation with thrombin, collagen or ADP.

4) β2-G-I causes significant alteration of the ADP-induced aggregation of GFP. Aggregation induced by thrombin, collagen, arachidonic acid or PAF-acether, however is not altered by β2G-I.

It is suggested, that pelleting during centrifugation causes irreversible rearrangements in the membrane of platelets.