PROS1 and infection: As for to SARS-CoV and MERS-CoV, several types of representative neutralizing antibodies such as monoclonal antibodies, their functional antigen-binding fragment and the single-chain variable region etc., has been found to block the binding between receptor-binding domain(RBD) region of S protein with ACE2 receptor and then to inhibit the infection (Jiang et al., 2020).