| Popis: |
In Hep 3B cells, in which the combination of IL-6 and IL-1 had previously been found to be required for SAA induction, checkerboard titration of these cytokines showed that each cytokine played an enabling role, permitting the effect of the other cytokine to be perceived at the level of synthesis in a dose-related manner. Dexamethasone (dex) markedly potentiated SAA induction by both monocyte conditioned medium and IL-6 plus IL-1α, although it had no effect when employed alone. SAA induction by these cytokine preparations in the presence of dex was inhibited by TGFs-1 at concentrations of 4-10 ng/ml. The combination of IL-6 and TNFa was capable of SAA induction at levels about 20-60% of those achieved by IL-6 and IL-la. [TGFs-1 (4-10 ng/ml) inhibited SAA induction by cytokine.] These cytokine effects were detectable at the pretranslational level. These data suggest that SAA synthesis in human hepatocytes might be regulated by IL-6, IL-1, TNFa, and TGFs and corticosteroids in various combinations. |
