Triggered human neutrophils were able to maintain released elastase in an active form in the presence of purified alpha-lproteinase inhibitor (a-l-PI), serum or bronchoalveolar lavage fluid (BAL). The accumulation of free elastase activity was associated with a decrease in the ability of the a-l-PI to inhibit porcine pancreatic elastase, an increase in proteinase activity associated with a-2-mac*roglobulin, and the oxidation of a-l-PI to a molecule containing four methionine sulfoxide residues. Neutrophils used both hypochlorous acid and long-lived N-chloroamines to oxidize the a-l-PI, but hypochlorous acid was preferentially used for suppressing the activity of the antiproteinase over short distances whereas the N-chloroamines were effective even when the phagocytes and a-l-PI were physically separated. Sodium dodecyl sulfate-polyacryhamide gel electrophoresis of purified a-l-PI, serum, or BAL that had been incubated with triggered neutrophils revealed that the released neutrophil elastase was not complexed with the antiproteinase and that a portion of the a-l-PI had undergone proteolysis. These data suggest that the presence of free neutrophil elastase as well as inactive, oxidized,and proteolyzed a-l-PI in fluids recovered from inflammatory sites in vivo could be directly mediated by triggered neutrophils alone.

Abstract. Human phagocytes can be triggered to generate large quantities of long-lived nitrogen-chlorine derivatives. This class of oxidants can be detected as early as 5 min after the addition of phorbol myristate acetate or opsonized zymosan particles. Unlike all other oxygen metabolites known to be generated by phagocytes, the nitrogen-chlorine compounds can be readily detected in cell supernatants 90 min after stimulation. The generation of these oxidants is linear with neutrophil concentration, favored at alkaline pH, and inhibited by supraphysiologic concentrations of iodide or bromide. The oxidants are hydrophilic in nature and have a halflife ranging from 5 h at 370C to >100 h at 40C. Gel filtration chromatography of the accumulated nitrogenchlorine derivatives revealed that the oxidants generated by neutrophils or monocytes are a complex mixture of products whose Mr range from 150-5,000. One-half of the nitrogen chlorine derivatives migrate as a single peak with an Mr of -150. Amino acid analysis of this fraction identified the I-amino acid, taurine, as the single nitrogenous compound present. Neutrophils triggered in the presence of serum albumin accumulated increased amounts of the nitrogen-chlorine derivatives while continuing to generate their endogenous low M, oxidants.

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