The soluble form of the leukocyte membrane antigen CD14 is known to increase the sensitivity of endothelial and epithelial cell lines to bacterial lipopolysaccharide (LPS). This molecule also directly induces cytokine production in monocytes. Here, the effect of sCD14 and LPS on the release of IL-6 and IL-8 by human bronchial epithelial cells (HBECs) was studied. Soluble CD14 induced cytokine production both in the presence and absence of LPS. In addition, neither sCD14 nor anti-CD14 monoclonal antibody which blocks the interaction of LPS with CD14 had any effect on the binding of LPS to HBECs. These data suggest that sCD14 may induce the release of IL-6 and IL-8 from HBECs. However, the binding of LPS to bronchial epithelium appears to be mediated by CD14-independent mechanisms.