The duration of each step was determined experimentally using specific controls (Supporting Fig. 2). The results clearly show that a decrease in HCVcc infection was only observed when EGCG was present during virus infection (Fig. 3A, second, third, fourth, and sixth bars in the bar-graph), and that there was no effect of EGCG if added as a pretreatment of the cells (Fig. 3A, first bar) or postinfection (Fig. 3A, fifth bar). These results suggest that EGCG inhibits an early step of the HCV life cycle, most likely the entry step. To confirm the effect of EGCG on HCV entry, HCVpp harboring E1 and E2 of different genotypes were produced. HCVpp

infectivity was reduced by approximately 10-fold with a concentration of 50 μM, confirming the effect of EGCG on HCV entry, whatever the genotype used (Fig. Palbociclib order 3B). However, Wnt tumor some differences between genotypes could be observed at a lower EGCG concentration (5 μM). In contrast, vesicular stomatitis virus (VSV)pp entry was much less inhibited. These results suggest that the antiviral activity of EGCG is directed against HCV envelope glycoproteins and is genotype independent. Together, these data indicate that

EGCG inhibits HCV entry in a genotype-independent manner. Although the above data indicate that EGCG has a strong effect on HCV entry, we cannot exclude additional effects on other steps of the HCV life cycle. To analyze the effect of EGCG on HCV genome replication, Huh-7 cells were electroporated with in vitro transcribed assembly-defective JFH1-ΔE1/E2-Luc RNA, to bypass the entry step, and avoid any interference with late steps of the HCV life cycle. EGCG had no major effect on HCV replication, even after a longer period of treatment (96 hours postelectroporation) (Fig. 4A). In contrast, IFN-α, at 2 IU/mL, approximately twice the IC50 calculated for HCVcc in Huh-7 cells (1.15 IU/ml), 28 induced 1 log10 decrease of luciferase activity. To determine whether EGCG could have any effect on HCV assembly or secretion, intra- and extracellular core protein was quantified in infected

cells treated postinfection with 50 μM of EGCG for 70 hours. The amount Ribonucleotide reductase of core in the culture supernatant reflects the quantity of secreted viral particles. A slight, but not significant (P = 0.10), decrease in intracellular core was observed in the presence of EGCG (Fig. 4B). This cannot be explained by a decrease in RNA replication, because it has been shown above that EGCG has no effect on HCV replication (Fig. 4A). However, the quantification of extracellular core showed a small, but not significant (P = 0.10), increase of secreted core in the presence of EGCG, as compared to the nontreated control (Fig. 4B), showing that EGCG does not impair viral secretion. Similar experiments were performed with JFH1-ΔE1/E2 to avoid reinfection of the cells and to quantify the levels of extracellular core resulting from cell lysis.