Send to

Choose Destination
See comment in PubMed Commons below
Am J Respir Cell Mol Biol. 1995 Mar;12(3):351-7.

Human neutrophil defensin and serpins form complexes and inactivate each other.

Author information

Will Rogers Pulmonary Research Laboratory, University of California at Los Angeles 90024-1736.


Defensins, antimicrobial and cytotoxic peptides of neutrophils, bind to and are inactivated by blood proteins. We identified defensin interactions with alpha 1-proteinase inhibitor (alpha 1-PI), alpha 1-antichymotrypsin (alpha 1-ACT), alpha 2-antiplasmin (alpha 2-AP), and antithrombin III (AT III) and examined defensin binding to alpha 1-PI and alpha 1-ACT in more detail. Defensin interactions with either alpha 1-PI or alpha 1-ACT were not affected by iodoacetamide or high salt concentration. Preincubation of alpha 1-ACT or alpha 1-PI with increasing concentrations of defensin resulted in a progressive decrease of antiprotease activity of both inhibitors against cathepsin G and antiprotease activity of alpha 1-PI against human neutrophil elastase. At higher concentrations, defensin also ablated the inhibitory effect of normal human serum on cathepsin G and human neutrophil elastase. Both alpha 1-PI and alpha 1-ACT inhibited defensin cytotoxicity toward the human lung carcinoma cell line A549, whereas the elastase inhibitor antileukoprotease did not. Complex interactions between serpins and defensin may have a role in regulating inflammatory processes.

[Indexed for MEDLINE]
PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Atypon
    Loading ...
    Support Center