ALPHA-1-ANTITRYPSIN HUMAN-LEUKOCYTE ELASTASE COMPLEXES IN BLOOD - QUANTIFICATION BY AN ENZYME-LINKED DIFFERENTIAL ANTIBODY IMMUNOSORBENT-ASSAY AND COMPARISON WITH ALPHA-2-PLASMIN INHIBITOR PLASMIN COMPLEXES

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  • 1 January 1983
    • journal article
    • research article
    • Vol. 61  (5) , 842-849
Abstract
An enzyme-linked immunosorbent assay (ELISA) was developed for the quantification of .alpha.1-antitrypsin human leukocyte elastase (.alpha.1AT-E) complexes. In the ELISA, the .alpha.1AT-E complex is bound to a surface by rabbit antileukocyte elastase antibody, and the inhibitor-proteinase complex is quantified by a 2nd antibody, rabbit anti-.alpha.1-antitrypsin F(ab'')2, labeled with alkaline phosphatase. .alpha.1AT-E complexes were detected when a final concentration of 2.2 nmol/l of leukocyte elastase was added to plasma. The concentration of these complexes increased with additional elastase. In clotting blood, .alpha.1AT-E complexes were generated in parallel with the conversion of 125I-fibrinogen to fibrin, whereas .alpha.2-plasmin inhibitor-plasmin (.alpha.2PI-P) complexes were not formed. The concentration of .alpha.1AT E-complexes in 19 of 21 controls was < 2.2 nmol/l. Patients with laboratory evidence for disseminated intravascular coagulation (DIC) demonstrated elevated .alpha.2 PI-P complexes with either increased or normal concentrations of .alpha.1AT-E complexes. Patients without evidence for DIC, but who demonstrated prolonged reptilase clotting times, were studied. This group had increased .alpha.1AT-E but normal .alpha.2PI-P complex levels, raising the possibility that elastase release in vivo may be accompanied by limited degradation of fibrinogen. These assays, thus, serve as useful probes for the study of leukocyte activation and of the interactions between cellular and plasma proteolytic enzyme systems.