An ACE2 microbody containing a single immunoglobulin Fc domain is a potent inhibitor of SARS-CoV-2

Tada T, Fan C, Chen JS, Kaur R, Stapleford KA, Gristick H, Dcosta BM, Wilen CB, Nimigean CM, Landau NR

10.1016/j.celrep.2020.108528 01/12/2020

PMID: 33326798


Soluble forms of angiotensin-converting enzyme 2 (ACE2) have recently been shown to inhibit severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. We report on an improved soluble ACE2, termed a “microbody,” in which the ACE2 ectodomain is fused to Fc domain 3 of the immunoglobulin (Ig) heavy chain. The protein is smaller than previously described ACE2-Ig Fc fusion proteins and contains an H345A mutation in the ACE2 catalytic active site that inactivates the enzyme without reducing its affinity for the SARS-CoV-2 spike. The disulfide-bonded ACE2 microbody protein inhibits entry of SARS-CoV-2 spike protein pseudotyped virus and replication of live SARS-CoV-2 in vitro and in a mouse model. Its potency is 10-fold higher than soluble ACE2, and it can act after virus bound to the cell. The microbody inhibits the entry of β coronaviruses and virus with the variant D614G spike. The ACE2 microbody may be a valuable therapeutic for coronavirus disease 2019 (COVID-19) that is active against viral variants and future coronaviruses.

Keywords: ACE2 transgenic; D614G; Fc fusion; SARS-CoV-2; coronavirus; entry inhibitor; lentiviral pseudotype; microbody; soluble ACE2; spike protein.