Stimulatory effect of inflammatory cytokines on alpha 1-antichymotrypsin expression in human lung-derived epithelial cells.

Although it is a well known fact that hepatocytes are the primary source of plasma proteinase inhibitors, including alpha 1-antichymotrypsin, this protein has also been detected in lung epithelial cells, which may suggest its local production. We have demonstrated that lung-derived epithelial cells are capable of synthesizing high levels of alpha 1-antichymotrypsin. In normal bronchial epithelial cells, as well as in the HTB55 human adenocarcinoma cell line, alpha 1-antichymotrypsin synthesis was under the control of inflammatory cytokines, of which oncostatin M was the most potent stimulator. This finding is consistent with a role for this inhibitor in protecting the lung epithelium from damage by chymotrypsin-like enzymes released from phagocytes such as neutrophils following pathogen invasion.