The study isolates and humanizes an ACE2-blocking monoclonal antibody (h11B11) showing potent inhibitory activity against SARS-CoV and SARS-CoV-2 lineages. Therapeutic and prophylactic administration in a mouse model alleviated and prevented viral replication and associated syndromes. High-dose injections in cynomolgus monkeys showed no significant toxicity. Structural analysis revealed the antibody's mechanism involves hindering and competing with the RBD for ACE2 binding. This suggests h11B11 as a potential therapeutic countermeasure.
