PROS1 and infection: According to cell culture mechanisms, a family of Interferon-Inducible Transmembrane proteins (IFITM) could limit S protein-dependent access in HCoV-229E and HCoV-NL63, which would also lead to intense reduction of the infection in SARS-CoV and MERS-CoV (Huang et al., 2011; Wrensch et al., 2014).