Precipitation of Soluble Fibrin Monomer Complexes by Lysosomal Protein Fraction of Polymorphonuclear Leukocytes

Abstract

A lysosomal protein fraction (LPF) isolated from rabbit PMN leukocytes is able to interact with soluble fibrin monomer complexes to form a precipitate. The reaction seems to be nonenzymatic and similar to that induced by polycationic protamine sulfate and polyanionic polyanethol sulfonate (Liquoid). The fibrin precipitating activity of LPF is thermostable and destroyed by proteolysis. The reaction between LPF and soluble fibrin monomer complexes is inhibited by 1 M urea. Heparin in a concentration of 100 U/ml has no effect on precipitate formation. The fibrin precipitating activity of LPF suggests that this material may be important in producing intravascular fibrin deposition in those situations in which there is destruction of PMN leukocytes and a concurrent rise of soluble fibrin monomer complexes in the circulation.