[Development of an engineered ACE2 decoy for COVID-19 therapy.]

It has been passed four years since the pandemic caused by the severe acute respiratory syndrome-2 (SARS-CoV-2) that began in 2019. Since June 2020, we have been working on a project to develop a therapeutic drug using receptor decoys, even though we cannot predict how long the pandemic will last or how long our daily lives will be restricted. This receptor decoy utilizes Angiotensin-converting enzyme 2 (ACE2), which is the receptor for SARS-CoV-2, and involves introducing mutations that enhance its binding ability with the spike protein of SARS-CoV-2. This high-affinity ACE2, acting as a decoy protein, is a strategy to inhibit viral infection and to expect therapeutic effects by replacing the endogeneous ACE2 that SARS-CoV-2 binds to with ACE2 decoy. This paper introduces the development of ACE2 decoys that have progressed through collaborative research with many researchers outside the field of virology.