Figure 5.
IL-TIF activity requires IL-10Rβ chain. (A and B) HepG2 cells, transfected with the pGRR5 luciferase construct, were preincubated with 20 μg/ml anti-gp130 antibodies (A) or anti-IL-10Rβ antibodies (B) and then stimulated by IL-6 (300 units/ml), IL-TIF (1% supernatants from IL-TIF-transfected HEK293 cells), or left unstimulated. Luciferase activity was monitored 2 h later. The results are expressed in arbitrary units including standardization by using renilla luciferase internal control. The data correspond to the mean of duplicate cultures and are representative of three independent experiments. Supernatants from mock-transfected HEK293 cells had no effect in the assay (data not shown). (C) HepG2 cells were preincubated with anti-IL-10Rβ antibodies and stimulated with IL-TIF as indicated above. After 2 h, total RNA was extracted and RT-PCR amplification was performed with oligonucleotides specific for SAA and β-actin. PCR products were analyzed by agarose gel electrophoresis.