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Thromb Haemost 1990; 64(01): 172-176
DOI: 10.1055/s-0038-1647276
Original Article
Schattauer GmbH Stuttgart

The Binding of Phosphatidylglycerol Liposomes to Rat Platelets Is Mediated by Complement

H C Loughrey
1   The University of British Columbia, Faculty of Medicine, Department of Biochemistry, Vancouver, B.C., Canada
,
M B Bally
1   The University of British Columbia, Faculty of Medicine, Department of Biochemistry, Vancouver, B.C., Canada
2   The Canadian Liposome Company, North Vancouver, B.C., Canada
,
L W Reinish
1   The University of British Columbia, Faculty of Medicine, Department of Biochemistry, Vancouver, B.C., Canada
,
P R Cullis
1   The University of British Columbia, Faculty of Medicine, Department of Biochemistry, Vancouver, B.C., Canada
2   The Canadian Liposome Company, North Vancouver, B.C., Canada
› Author Affiliations
Further Information

Publication History

Received 10 October 1989

Accepted after revision 27 April 1990

Publication Date:
25 July 2018 (online)

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Summary

Previous work has shown that intravenous administration of phosphatidylglycercol (PG) containing liposomes to rats results in a rapid transient decline in platelet count (1). Here the interactions of PG liposomes with rat platelets in vitro have been examined with the aim of charactenzing factors associated with the decline. It is shown that PG liposomes induce formation of rat (but not human) platelet-liposome microaggregates in vitro. The PG liposome dependent thrombocytopenia observed in vivo can therefore be attributed to sequestration of PG liposome-platelet aggregates. Further, the aggregation of platelets with PG liposomes, which can be moni ored as a reduction in platelet count using a coulter counter, is shown to be mediated by a serum complement fgctor, likely C3b. This is indicated by a requirement of plasma for the in vitro reduction in platelet count induced by PG liposomes, and the inhibition of this effect by heat treatment of plasma, by incubation of plasma with purified cobra venom factor, or by removal of C3 from plasma.