Figure 2
Heparin at physiological concentration in human plasma can stimulate HBV in vitro infection. (a) An illustration of experimental design. (b) Human plasma, with or without heat pre-treatment, enhanced HBV in vitro infection. HBsAg (left panel) and HBeAg (right panel) were measured at 9 dpi by ELISA. HepG2-NTCP-AS cells were infected with HBV serum at MOI 300–3000 in the presence of 1.2% PEG. Human plasma was supplemented with fresh heparin before adding to the cell culture to prevent coagulation. Data are shown as mean ± SEM of at least three independent experiments (**p < 0.01). Dashed lines represent the cutoff value of the background noise in the ELISA assays. (c) Heparin alone without human plasma can still enhance HBV infection. (d) Heparin at physiological concentrations (1 to 5 µg/ml)14,15,16 can enhance HBV infection in a dose-response experiment. HepG2-NTCP-AS cells were infected with HBV serum at MOI 300–3000 at 37 °C for 24 hours. Increasing concentrations of heparin (0, 1.5, 4.5, 13.5, 40, 120 μg/ml) were used in the presence of 1.2% PEG or 4% PEG. (*p < 0.05). (e) Treatment with PreS1 lipopolypeptide inhibited heparin-enhanced infection of HepG2-NTCP-AS cells. These HepG2-NTCP-AS cells were infected with HBV serum in the presence of 1.2% PEG with and without 4.5 μg/ml heparin. HepG2-NTCP-AS cells were pre-incubated with 500 nM PreS1 peptide for 30 minutes before infection. (*p < 0.05). (f) Heparin-enhanced HBV infection can be abrogated by the continuous presence of a nucleoside analog 3TC (10 uM), from 1 to 9 dpi. HepG2-NTCP-AS cells were infected with HBV serum in the presence of 1.2% PEG, with and without 4.5 μg/ml heparin.
