Fig. 5.

Fucoidan suppresses the replication of HBV and increases the production of type I IFN via activating the ERK pathway. HepG2.2.15 cells were left untreated or pretreated with U0126 (2 μM) for 2 h, followed by treatment with fucoidan (100 μg/ml) for 24 h. a Phospho-ERK and total ERK were detected by western blot. GAPDH was served as a loading control. b The mRNA level of IFN-α in cells was determined by quantitative RT-PCR. c The production of IFN-α in the culture supernatant was evaluated by ELISA analysis. d The HBV DNA replicative intermediates in the cells were detected by quantitative PCR. e, f The levels of HBsAg (e) and HBeAg (f) in the culture medium were measured by ELISA analysis. * p < 0.05, ** p < 0.01, N.S., not significant. g The expression of HBcAg in the cells was determined by western blot analysis. All the experiments were repeated at least three times independently