Quantitation Of Human Granulocyte Protease Inhibitors In Non-Purulent Bronchial Lavage Fluids

The predominant inhibitors of granulocyte proteases in plasma (α1-antitrypsin, α1-antichymotrypsin, and α2-macroglobulin) were quantitated in unconcentrated bronchial lavage fluids obtained from non-infected individuals, together with the acid-stable low molecular weight inhibitor with activity against granulocyte elasto-lytic and chymotrypsin-like enzymes. This latter inhibitor accounted for about 90 % of the total molar concentration of granulocyte protease inhibitors in the bronchial lavage fluids. The remaining 10% consisted mostly of α1-anti-trypsin and α1-antichymotrypsin. About 85 % of the bronchial inhibitor was in a free form with preserved enzyme reactivity. The remaining 15% of the immunoreactive bronchial inhibitor exhibited a molecular size indicating complexation with enzymes. The major portion of α1-antitrypsin and α1-antichymotrypsin showed electrophoretic mobilities and molecular sizes similar to the native proteins but had no enzyme reactivity.