Thromb Haemost 1987; 58(03): 936-942
DOI: 10.1055/s-0038-1646019
Original Article
Schattauer GmbH Stuttgart

Receptor Mediated Binding of the Fibrinolytic Components, Plasminogen and Urokinase, to Peripheral Blood Cells

Lindsey A Miles
The Department of Immunology, Research Institute of Scripps Clinic, La Jolla, CA, USA
,
Edward F Plow
The Department of Immunology, Research Institute of Scripps Clinic, La Jolla, CA, USA
› Author Affiliations
Further Information

Publication History

Received 16 February 1987

Accepted after revision 24 June 1987

Publication Date:
23 July 2018 (online)

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Summary

Glu-plasminogen binds to platelets; the monocytoid line, U937, and the human fetal fibroblast line, GM1380 bind both plasminogen and its activator, urokinase. This study assesses the interaction of these fibrinolytic proteins with circulating human blood cells. Plasminogen bound minimally to red cells but bound saturably and reversibly to monocytes, granulocytes and lymphocytes with apparent Kd values of 0.9-1.4 μM. The interactions were of high capacity with 1.6 to 49 × 105 sites/cell and involved the lysine binding sites of plasminogen. Both T cells and non-rosetting lymphocytes and two B cell lines saturably bound plasminogen. Urokinase bound saturably to gianulocytes, monocytes, non-rosetting lymphocytes and a B cell line, but minimally to T cells, platelets and red cells. Therefore, plasminogen binding sites of high capacity, of similar affinities, and with common recognition specificities are expressed by many peripheral blood cells. Urokinase receptors are also widely distributed, but less so than plasminogen binding sites. The binding ol plasminogen and/ or urokinase to these cells may lead to generation of cell- associated proteolytic activity which contributes to a variety of cellular functions.