To determine whether the differential susceptibility of the two hepatoma cell lines to HCoV-OC43 infection is due to a difference in virus entry or a postentry replication event, we compared the susceptibility of the two cell lines to lentiviral particles pseudotyped with envelope proteins of HCoV-OC43, influenza A virus (IAV), vesicular stomatitis virus (VSV), or Lassa fever virus (LASV) by using a luciferase assay to examine the entry efficacy. The gene discussed is ERVW-1; the disease is infection.