ACE2 and infection: While the expression of ACE2 receptors in these cells correlates with the permissiveness of HCoV-NL63 infection (Milewska et al., 2014; Smith et al., 2006), the soluble form of ACE2 might abrogate infection (Hofmann et al., 2005; Jia et al., 2009), constituting a potential non-functional truncated form of ACE2 (Onabajo et al., 2020).