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Disaggregation of Aggregated Platelets by Savignygrin, a αIIbβ3 Antagonist from Ornithodoros Savignyi

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Abstract

Ticks control their host's hemostatic system by secretion of bioactive components during feeding that inhibit blood coagulation and platelet aggregation. Dissolution of platelets that have already aggregated can enhance control over the hemostatic system. It has been shown that disaggregation of aggregated platelets by the enzyme apyrase was accompanied by a shape change from the aggregated spherical form back to the discoid form associated with un-activated platelets. The present study concerns the disaggregation effect of the αIIbβ3 antagonist, savignygrin. Aggregated platelets that were disaggregated by savignygrin and platelets pre-incubated with savignygrin before activation with ADP, retained a spherical form similar to platelets disaggregated by the fibrinogenolytic enzyme plasmin. The number of pseudopods were however, markedly reduced suggesting a disruption of the focal adhesion points that act as a localization point of αIIbβ3. These results are concurrent with targeting of αIIbβ3 and dissociation of fibrinogen from its receptor, once aggregation has taken place. This is the second mediator of platelet disaggregation found in soft ticks and suggests that disaggregation of aggregated platelets might play an important part in the anti-hemostatic strategy of ticks.

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Authors and Affiliations

  1. Department of Biochemistry, Faculty of Biological and Agricultural Sciences, University of Pretoria, Pretoria, 0002, South Africa

    Ben J. Mans, Abraham I. Louw & Albert W.H. Neitz

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  1. Ben J. Mans
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  2. Abraham I. Louw
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  3. Albert W.H. Neitz
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Correspondence to Albert W.H. Neitz.

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Mans, B.J., Louw, A.I. & Neitz, A.W. Disaggregation of Aggregated Platelets by Savignygrin, a αIIbβ3 Antagonist from Ornithodoros Savignyi . Exp Appl Acarol 27, 231–239 (2002). https://doi.org/10.1023/A:1021613001297

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  • DOI: https://doi.org/10.1023/A:1021613001297

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