Induction of MDC expression by IL-4 and IL-13. Monocytes were incubated for 24 hours with increasing concentrations of IL-4 and IL-13 (dose-response) or with IL-4 or IL-13 (20 ng/mL) for different times (time-course). Ten micrograms of total RNA was used in Northern blot analysis. Results of one experiment representative of two performed are shown. Autoradiography were obtained after 12 hours of exposure. Etidium bromide staining of the membrane is shown in the lower part of the figure. (A) Time-course of IL-4. (B) Time-course of IL-13. (C) Dose-response of IL-4. (D) Dose-response of IL-13.