The influence of granulocyte elastase-like proteinse (ELP) on platelet aggregation was investigated by using the method in which agonist such as ADP, epinephrine, thrombin, collagen, arachidonic acid, A 23187 or ristocetin, cofactor such as fibrinogen or von Willebrand factor, or the suspended platelets in calcium free Hepes Tyrode albumin buffer was respectively incubated with ELP.
ELP treatment of agonists except collagen or thrombin resulted in no change of the ability to induce aggregation. On the other hand, the treated collagen showed the decrease of the ability, however, the treated thrombin showed the slight increase of the ability. ELP treatment of cofactor such as fibrinogen or vWF resulted in the decrease of the cofactor activity corresponding to the change of its molecular form. Platelet aggregation in ELP treated platelets was markedly decreased by agonist such as thrombin, collagen, epinephrine or ristocetin, while it was not as greatly decreased by arachidonic acid, ADP or A 23187.
These results demonstrated that the influence of ELP on platelet aggregation was mainly caused by direct inactivation of platelets. ELP also acted on cofactor such as fibrinogen or vWF and a part of agonist such as collagen or thrombin, and subsequently influenced upon the aggregation.
