ACE2 and viral infectious disease: The first 4 mAbs have epitopes fully or partially overlapping with the receptor-binding motif (RBM) on the RBD thereby blocking viral entry by preventing ACE2 from binding to RBM, whereas non-RBM mAbs such as sotrovimab appears to block viral infection by sterically interfering the viral membrane fusion after ACE2 engagement with RBM (9).