Fibrinogen is the receptor for the endogenous lectin of human platelets

Abstract

Washed human platelets activated by .alpha.-thrombin, .gamma.-thrombin, thrombocytin or ionophore A23187 lose their disk shape, produce pseudopodia and become cohesive. This cohesiveness is accompanied by the expression of an endogenous hemagglutinin which, although apparently bound to the platelet membrane, is dependent on cell secretion. The interaction of this agglutinin with appropriate receptors on other platelets is believed to be responsible for aggregation. Platelets which lack agglutinin activity but which have function can be prepared. Afibrinogenemic platelets lack receptor activity. Fibrinogen is the receptor for the agglutinin secreted by activated platelets.