Inhibition of elastase by canine serum: demonstration of an acute phase response

Canine serum alpha 1-proteinase inhibitor is not a major acute phase reactant in the dog, unlike the equivalent protein in humans. The possibility that an alternative protease inhibitor system is stimulated during the acute phase response in the dog was investigated. alpha 2-macroglobulin was not an acute phase reactant, but an inhibitor of elastase was identified in canine serum which could be separated from proteinase inhibitor by gel filtration and which was shown to be an acute phase reactant. This protein has been named canine elastase inhibitor.