Potency of antileukoprotease and alpha 1-antitrypsin to inhibit degradation of fibrinogen by adherent polymorphonuclear leukocytes from normal subjects and patients with chronic granulomatous disease.

Abstract

We have studied the relative efficacy of antileukoprotease (ALP) and alpha 1-antitrypsin (alpha 1AT) to inhibit the degradation of substrate by polymorphonuclear leukocytes (PMN) attached onto a fibrinogen matrix. PMN elastase activity was assayed by radioimmunoassay of a specific 21-residue cleavage product from the amino terminus of the A alpha chain, A alpha (1-21), of fibrinogen. The adherence of PMN (1.0 x 10(6)) to a fibrinogen matrix was facilitated by incubation with recombinant tumor necrosis factor-alpha (1 nM). Subsequently, the cells were exposed to inhibitors before stimulation with cytochalasin B and formylmethionyl-leucylphenylalanine. Under these conditions, ALP inhibited A alpha (1-21) formation with an IC50 of 85 +/- 30 nM and alpha 1AT gave an IC50 of 220 +/- 98 nM (mean +/- SD). The effect of oxidant production on A alpha (1-21) formation was evaluated by comparing the effect of PMN from normal subjects with PMN from subjects with X-linked NADPH oxidase deficiency. Stimulation of PMN from the latter subjects in a similar fashion as described above resulted in the formation of 40 +/- 4 pmol/ml A alpha (1-21), or approximately twice the amount seen with cells from normal subjects. Preincubation with ALP or alpha 1AT in a concentration range between 10 to 900 nM resulted in an IC50 of 50 +/- 13 nM for ALP compared with 150 +/- 21 nM for alpha 1AT. Both inhibitors are more effective to prevent fibrinogen degradation caused by chronic granulomatous disease (CGD) PMN than by normal PMN despite the fact that CGD PMN generated more A alpha (1-21) than did normal PMN.(ABSTRACT TRUNCATED AT 250 WORDS)