PROS1 and infection: During the infection process, human coronavirus (HCoVs), especially SARS-CoV-2, mediated by S protein, firstly bind to gangliosides (Fantini et al., 2021), then simultaneously to heparan sulfate (HS) and hACE-2 through recognition by the viral surface antigens, RBD (aa 330–583, for the SARS-CoV-2 RBD) (Clausen et al., 2020); Lan et al., 2020).