The copy number of EV71 was detected by real-time PCR analysis. Inhibitor treatment Cells were incubated with 0.5 mg/ml tunicamycin (Sigma) or 3.0 mM benzyl-α-GalNAc (Toronto Research Chemicals Inc.) at 37°C for 24 or 48 hours, respectively. After wash, the cells find more were subjected to virus infection. Neuraminidase treatment Cells were incubated with 0.5 to 25 mU of neuraminidase (Roche, 11080752001) with 4 mM CaCl2 in serum-free DMEM at 37°C for 3 hours followed by wash and EV71 infection. For detecting cell surface SCARB2, the neuraminidase treated cells (10 mU) were incubated with mouse anti-SCARB2

antibody (1:100) and FITC-conjugated goat anti-mouse antibody (1:500) at 4°C for 30 minutes. After wash for three times, the cells were analyzed by FACS caliber with Cell Quest Pro software (BD Biosciences). Lectin competition Cells were incubated with 2 to 125 μg/ml of MAA (maackia amurensis) or SNA (sambucus nigra) at 4°C for 30 minutes. After wash, the cells were subjected to learn more virus infection. Fetuin and

asialofetuin treatment RD cells (2×104) were incubated with 2/25 μg/ml of fetuin or asialofetuin at 4°C for 30 minute followed by wash and EV71 MP4 infection (M.O.I = 100). The binding of EV71 was measured by ELISA assay. Isolation of cell membrane glycoproteins and sialylated proteins RD cells were harvested and homogenized in ice-cold homogenization buffer (20 mM Tris–HCl, pH 7.5, 2.0 mM EDTA, 1.0 mM DTT and protein inhibitor cocktail) by using sonicator (Chrom Tech). Cell lysates were obtained by centrifugation and cell pellet was resolved in homogenization buffer. The collected membrane fractions from centrifugation were resuspended in homogenization buffer and analyzed by western blotting. Then, membrane

protein fractions were subjected to lectin affinity chromatography that was packaged with SNA and MAA agarose Demeclocycline beads (EY Laboratories). The sialylated glycoproteins were eluted by 20 mM ethylenediamine and all of the fractions were collected for further characterization and analyzed by western blotting with anti-SCARB2 monoclonal antibody. Immunoprecipitation assay The purified sialylated glycoproteins were incubated with 5 units of neuraminidase at 4°C for 16 hours. The reaction mixture was transferred to an eppendorf which contained EV71 viral particles, anti-EV71 antibody, and protein G agarose beads. The reaction was incubated at 37°C for 12 hours and the bound proteins were pulled down by centrifugation. After unbound proteins were removed, the agarose beads were washed with PBS buffer for three times and added glycin-HCl (pH 2.0) to break the bindings. The reaction solution was centrifuged to remove Protein A agarose beads and the bound glycoproteins were concentrated and analyzed by western blotting with anti-SCARB2 monoclonal antibody. Interactions of EV71 to recombinant hSCARB2 – Viral-Overlaying Protein Binding Assay (VOPBA) Recombinant h-SCARB-2 protein was purchased from Abscience (11063-H03H).