IL-29 induces production of IL-6 and IL-8 by rheumatoid arthritis synovial fibroblasts. MH7A cells were cultured with IL-29 (1, 10 and 100 ng/ml) or TNF-α (10 ng/ml; positive control) for 24 hours, and the production of IL-6 (A) and IL-8 (B) were measured by ELISA. Because the effects of IL-29 at 1 ng/ml on the production of IL-6 and IL-8 in MH7A cells are similar to the medium control group, the data from IL-29 at 1 ng/ml in MH7A are not shown. MH7A cells were also cultured in the presence or absence of IL-29 (100 ng/ml) for 24 hours, then cell viability was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay (C). The data present the mean ± SD for three independent experiments. *P < 0.05 vs medium control. **P < 0.01 vs medium control.