Preparation and characterization of a monoclonal antibody that inhibits human neutrophil elastase activity

Neutrophil proteases are believed to play a role in the pathogenesis of a variety of human diseases. While many studies of proteases in models of disease have focused on elastase, neutrophils contain several proteases some of which share a high degree of homology. This report describes the production and characterization of an IgG1 murine monoclonal antibody (AHN-10) that reacts with human neutrophil elastase but not with the other major neutrophil neutral proteases: cathepsin G, proteinase 3, collagenase, or the newly purified neutral protease, esterase N. AHN-10 inhibited the elastinolytic activity of purified human neutrophil elastase and could detect elastase in alcohol-fixed cytospin preparations. The epitope recognized by AHN-10 was resistant to treatment with NaIO4, suggesting that the epitope is not a carbohydrate. AHN-10 should be useful for the immunolocalization of neutrophil elastase in tissue specimens and as a stable source of characterized antibody for quantitative identification of neutrophil elastase.