Release of IL-1β via IL-1β-Converting Enzyme in a Skin Dendritic Cell Line Exposed to 2,4-Dinitrofluorobenzene

We used a mouse fetal skin dendritic cell line (FSDC) to study the effect of the strong allergen 2,4-dinitrofluorobenzene (DNFB) on interleukin (IL)-1beta release and IL-1beta receptor immunoreactivity. Stimulation with DNFB (30 minutes) increased IL-1 release without changing the mRNA levels of the protein. Furthermore, DNFB increased transiently the interleukin-1beta-converting enzyme (ICE) activity, as measured with its fluorogenic substrate Z-Tyr-Val-Ala-Asp-AFC. The ICE inhibitor Z-YVAD-FMK prevented the release of IL-1beta evoked by DNFB. Incubation of the cells with DNFB (30 minutes) strongly increased IL-1beta receptor immunoreactivity. The rapid effect of DNFB on the release of mature IL-1beta, without inducing an increase of IL-1beta mRNA in FSDC, suggests a posttranslational modification of pro-IL-1beta by ICE activity.