TMPRSS2 and infection: Remarkably, our data showed that the effect of IVIG in preventing the infection of SARS-CoV-2 pseudovirus was attributed more to the blocking of cell surface molecules (e.g., ACE2, TMPRSS2) than to that of the SARS-CoV-2 spike protein, suggesting that IVIG preparations may confer a preventive effect against SARS-CoV-2 infection, regardless of variants.