Table 3 Biologic activities of human eosinophil granule proteins

Major Basic Protein (MBP)

Helminthotoxin and cytotoxin; bactericidal, platelet agonist; causes histamine release from basophils and rat mast cells; neutralizes heparin; increases bronchial reactivity to methacholine; provokes bronchospasm; activates neutrophils

Major Basic Protein-2 (MBP-2)

Cytotoxin; causes histamine release and LTC₄ release from basophils; causes superoxide and IL-8 release from neutrophils

Eosinophil Cationic Protein (ECP)

Helminthotoxin, neurotoxin, weak RNase activity, bactericidal, virucidal; inhibits cultures of peripheral blood lymphocytes; causes histamine release from rat mast cells; neutralizes heparin, alters fibrinolysis

Eosinophil –Derived Neurotoxin (EDN)

Neurotoxin, RNase activity, virucidal, weak helminthotoxin; inhibits cultures of peripheral blood lymphocytes; same as eosinophil protein X

Eosinophil Peroxidase (EPX)

In presence of H₂O₂ plus halide: kills microorganisms and tumor cells; causes histamine release and degranulation from rat mast cells; inactivates leukotrienes in absence of H₂O₂ plus halide; kills Brugia microfilariae; damages respiratory epithelium; provokes bronchospasm in primates. Generates reactive oxidants and free radicals