ACE2-IgG1 fusions with improved in vitro and in vivo activity against SARS-CoV-2

Abstract

SARS-CoV-2, the etiologic agent of COVID-19, uses ACE2 as a cell entry receptor. Soluble ACE2 has been shown to have neutralizing antiviral activity but has a short half-life and no active transport mechanism from the circulation into the alveolar spaces of the lung. To overcome this, we constructed an ACE2-human IgG1 fusion protein with mutations in the catalytic domain of ACE2. A mutation in the catalytic domain of ACE2, MDR504, significantly increased binding to SARS-CoV-2 spike protein, as well as to a spike variant, in vitro with more potent viral neutralization in plaque assays. Parental administration of the protein showed stable serum concentrations with excellent bioavailability in the epithelial lining fluid of the lung, and ameliorated lung SARS-CoV-2 infection in vivo . These data support that the MDR504 hACE2-Fc is an excellent candidate for treatment or prophylaxis of COVID-19 and potentially emerging variants.

Multivalent ACE2 engineering—A promising pathway for advanced coronavirus nanomedicine development

“…Also, Zhang et al [129] reported no observable toxicity when sACE2v.2.4 was intravenously administered (twice daily at 0.5 mg/kg) into mice for 5 continuous days. Several other research have consistently found no adverse effect with the use of ACE2 therapeutics [83] , [106] , [115] , [160] , [170] , [209] . Although higher-level clinical assessments are yet to surface, it is anticipated that the human origin of the ACE2 molecule itself may be important for their safe administration.…”

Engineering ACE2 decoy receptors to combat viral escapability

“… [ 74 ] MDR504 WT (H345A) 740 LALA b N.D. 3.5nM c 7.5nM c (WT) Ad5-hACE2-transduced/K18-ACE2 mice, Wuhan, pre-/post-infection, 15/30 mg/kg i.v. [ 79 ] WT (H374N/H378N) N.A WT 8.23 a 1.59 a (WT) 4.17 1.02 (WT) Ad5-hACE2-transduced mice, Wuhan, pre-/post-infection, 50mg/kg i.p. [ 73 ] T27W-foldon (WT) 615 WT 0.06 76.8 (WT) 0.21 24.1 (WT) [ 72 ] D30E-tetramer/hexamer (WT) 740 WT N.D. 0.07/0.06 nM 0.68 nM (WT) [ 69 ] a Avidity value of ACE2 dimer with collectrin domain and/or Fc.…”

“…The half-life of rhACE2 (i.e., non-Fc fusion) is reported to be ~3 h in humans [ 32 , 33 ]. However, fusion with wild-type IgG1-Fc and LALA-mutated Fc extended the half-life to 30–145 h in mice [ 24 , 74 , 79 ]. Lung distribution was also sufficient to achieve effective neutralization [ 24 , 79 ].…”

“…However, fusion with wild-type IgG1-Fc and LALA-mutated Fc extended the half-life to 30–145 h in mice [ 24 , 74 , 79 ]. Lung distribution was also sufficient to achieve effective neutralization [ 24 , 79 ]. Wild-type ACE2 decoys composed of wild-type or LALA-mutated Fc protect lungs from the original Wuhan strain in both prophylactic pre-infection and therapeutic post-infection regimens in hamsters [ 74 ], as well as K18-hACE2 transgenic or Ad5-hACE2 transduced mice ( Table 1 ) [ 79 ].…”

“…Lung distribution was also sufficient to achieve effective neutralization [ 24 , 79 ]. Wild-type ACE2 decoys composed of wild-type or LALA-mutated Fc protect lungs from the original Wuhan strain in both prophylactic pre-infection and therapeutic post-infection regimens in hamsters [ 74 ], as well as K18-hACE2 transgenic or Ad5-hACE2 transduced mice ( Table 1 ) [ 79 ]. The 3N39v4 decoy also exhibits therapeutic efficacy in hamsters infected with Wuhan [ 24 ], as well as omicron [ 26 ] strains.…”