es have been developed that rely on the full-length S protein. For example, a recombinant MERS-CoV S protein trimer (MERS S-2P) in prefusion conformation binds to the DPP4 receptor, as well as to the MERS-CoV NTD, RBD, and S2-specific neutralizing mAbs (Pallesen et al., 2017). Whereas this protein induces n