Fig. 6.

Effects of actinomycin D, cycloheximide, and brefeldin A on the IL-4- and IL-1β-stimulated increase in the release and expression of DAF. Cells were incubated for 24 h with IL-4 (10 ng/ml) or IL-1β (10 ng/ml) in the presence of various concentrations of actinomycin D (a–c), cycloheximide (d–f), or brefeldin A (g–i). The amounts of DAF shed into the culture supernatant (a,d,g), phosphatidylinositol-specific phospholipase C (PIPLC)-sensitive cell surface DAF (b,e,h), and DAF in the cell lysate (c,f,i) were then determined. Values are expressed as a percentage of that of the control in which the cytokines and inhibitors were absent. Values shown are means of three experiments. □, IL-4; ○, IL-1β; ▵, medium (without cytokine).