Platelet Aggregation and Release Triggered by Antibody to Platelet Factor 4 (PF 4 ) 1

Abstract

Summary

Antibodies to PF₄ were prepared in rabbits injected with highly purified human or pig PF₄ preparations. Anti-human PF₄ (AHPF₄) caused aggregation of human platelets in plasma or in washed suspension. Anti-pig PF₄ (APPF₄) antibody caused aggregation of washed pig platelets. Slight cross reaction between the two species was observed. The aggregation was accompanied by the platelet release reaction, however, platelet lysis was not evident even on addition of complement. Aggregation could be blocked by prostaglandin E₁, EDTA, potato apyrase, purified or crude PF₄ and heparin. It is believed that platelet aggregation and the subsequent release reaction are triggered by the interaction of antibody with PF4 antigen on or in platelets.