Anti-Heparin Activity of Lysosomal Cationic Proteins from Polymorphonuclear Leukocytes

Abstract

The lysosomal cationic proteins (LCP) of rabbit polymorphonuclear leukocytes have previously been shown to inhibit the formation of intrinsic prothrombin activator. That they also have anti-heparin activity is now demonstrated in a thrombin-plasma clotting system, the partial thromboplastin time test and the thromboplastin generation test. In thrombin clotting systems that contain antithrombin, LCP exhibit a clot-promoting effect. This activity does not appear to represent inhibition of antithrombin II or III or potentiation of the enzymatic action of thrombin. Rather it may be a direct effect on fibrinogen, or the reactions leading to fibrin formation.