(D) Control and EXT1-/- XG1 cells were exposed to SARS-CoV-2 pseudovirus or SARS-CoV-2 pseudovirus pre-treated with 250 IU/mL UF heparin for 30 min at 37°C. After incubation for 4h at 4°C, cells were lysed and binding was measured by ELISA. Data information: Data show the mean values and error bars are the SEM. Statistical analysis was performed using two-way ANOVA with Dunnett's multiple-comparison test. *P≤0.05, **P≤0.01 (n=3). 