ACE2 and viral infectious disease: Other potential therapeutic strategies, which are targeting ACE2, include blocking the surface ACE2 receptor using anti-ACE2 peptides or antibody.198 In a recent research, authors used a single-chain antibody fragment (scFv) or antibody to bind ACE2 and block the interaction between the S protein and ACE2.202 Additionally, as mentioned above, the main function is to regulate the RAS in several diseases.180,191,192 After viral infection, ACE2 downregulation in organs can disturb the balance between the RAS and ACE2/angiotensin-(1–7)/MAS axis, causing organ injuries.