Release of immunoreactive canine leukocyte elastase normally and in endotoxin and pancreatitic shock

A specific ELISA has been developed for the determination of alpha 1-proteinase inhibitor-bound leukocyte elastase in canine plasma and tissue fluids. Comparison of the sequence of the first 16 N-terminal amino acids of the isolated canine leukocyte elastase to other elastases indicated moderate homology with porcine pancreatic elastase and pronounced identity with human leukocyte elastase. Normal canine plasma contains about 66 micrograms/l leukocyte elastase measured as elastase alpha 1-proteinases inhibitor complexes. This represents about 70% of the total amount of leukocyte elastase released in plasma. The remaining 30% is bound by alpha 1 alpha 2-macroglobulin. Blood coagulation leads to a rapid release of elastase from the leukocytes. Slow intravenous infusion of a lethal dose of endotoxin into dogs is followed by a marked drop in leukocyte count and a simultaneous rapid increase in plasma leukocyte elastase concentration reaching a plateau level of 2-3 mg/l plasma. Bile-induced pancreatitis in dogs is accompanied by successive increases in leukocyte elastase levels in plasma as well as in peritoneal exudates, reaching a level of about 15 mg/l in the exudates during the late stages of disease.