Problem: To determine whether amnion cells produce interleukin (IL)-6 and -8 and thus may contribute to the high concentrations of these cytokines in amniotic fluid at term.
Method of study: Amnion-derived WISH cells were treated in culture with stimuli over 16 hr, and IL-6 and IL-8 concentrations in the conditioned media were measured by enzyme-linked immunosorbent assay or bioassay (IL-6 only).
Results: IL-8 production was approximately 5-fold higher than that of IL-6 under basal and stimulated conditions. Significant (by Dunnett's test after analysis of variance) stimulation of production of both cytokines was achieved by IL-1 beta (> 0.2 ng/ml), TNF alpha (> 10 ng/ml), and the phorbol ester, phorbol 12-myristate 13-acetate (> 2 nM), over a 16-hr culture period. Epidermal growth factor at 10 ng/ml induced a small increase in production of IL-8, but not of IL-6, whereas bacterial lipopolysaccharide had minimal effects on production of either cytokine. Basal and cytokine-stimulated IL-6 and IL-8 production was inhibited by dexamethasone at concentrations equal to or greater than 1 nM.
Conclusion: These findings suggest that amnion may be a significant contributor to the IL-6 and IL-8 content of amniotic fluid, and that WISH cells may be a suitable model for the study of cytokine production by amnion epithelial cells.