The specific binding of thrombin to human polymorphonuclear leucocytes.
Thrombin is a chemotaxin for polymorphonuclear leucocytes. In this paper the binding kinetics of 125I-labelled thrombin to purified polymorphonuclear leucocytes is characterized. At 4 degrees C, the 125I-labelled thrombin bound to the cells with a half-time of about 3 min. About 0.77 of the bound tracer dissociated upon addition of a surplus of unlabelled thrombin or hirudin. Each cell possessed about 50 receptors with a Kd of 18 pmol/l and about 6000 receptors with a Kd of 31 nmol/l. Although the binding affinity at 37 degrees C was 7-10-fold lower than that measured at 4 degrees C, it may be high enough to constitute the molecular basis for the reported thrombin-induced chemotaxis.
Sonne
O
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Institute of Physiology, University of Aarhus, Denmark.
D002634:Chemotaxis, Leukocyte; D006801:Humans; D009504:Neutrophils / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000378:metabolism*; D018179:Receptors, Thrombin; D013917:Thrombin / Q000378:metabolism*
D011956:Receptors, Cell Surface; D018179:Receptors, Thrombin; D013917:Thrombin