Scientific-grade soluble human ACE2 proven to inhibit SARS-CoV-2 Omicron variant

In a current examine posted to the bioRxiv* pre-print server, researchers reported that human angiotensin-converting enzyme 2 (ACE2) can affiliate with the receptor-binding area (RBD) and the Spike proteins of the Omicron variant.

The findings additional confirmed that sera samples from extreme acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-naïve and two-dose messenger RNA (mRNA)-vaccinated people did not neutralize Omicron in VeroE6 cells, whereas soluble ACE2/APN01 potently neutralized Omicron infections.

Study: Clinical grade ACE2 effectively inhibits SARS-CoV-2 Omicron infections. Image Credit: CI Photos/ShutterstockResearch: Scientific grade ACE2 successfully inhibits SARS-CoV-2 Omicron infections. Picture Credit score: CI Photographs/Shutterstock

The emergence of the SARS-CoV-2 Omicron variant has raised issues attributable to numerous mutations within the variant, which confers immune evasion and reduces the efficacy of SARS-CoV-2 vaccines, and neutralizes antibody therapies. The viral Spike protein–human ACE2 interplay is an important first step of SARS-CoV-2 an infection. Consultants consider that Omicron may carry mutations that change its dependency on ACE2 as an entry level, resulting in modifications in its tissue tropism and infectivity.

Research have proven that the Omicron variant is extra infectious than the opposite variants and it’s spreading quickly throughout the globe, accounting for many new circumstances of COVID-19 in lots of nations. Subsequently, you will need to determine therapies which can be efficient towards the Omicron variant.

The examine

Within the current examine, researchers rendered all prefusion state Spike protein mutations of Omicron in 3D utilizing molecular modeling strategies. The Omicron RBD modifications and the placement of mutations had been additional depicted in a 3D mannequin of the SARS-CoV-2 Spike RBD. In addition they modeled the N-glycosylation websites of the Spike protein beforehand reported and located that a number of the websites – N165, N234, N343 – immediately work together with ACE2 or its glycans.

With a view to check whether or not vaccinated sera might neutralize Omicron infections in VeroE6 cells, the authors collected sera from 4 SARS-CoV-2-naïve, mRNA-vaccinated healthcare staff, 5-7 weeks after the second dose of vaccination.

The researchers had beforehand reported that clinical-grade soluble ACE2 (APN01) can cut back the SARS-CoV-2 load in VeroE6 cells in a dose-dependent vogue utilizing an early-pandemic reference virus. Within the present examine, they investigated if APN01 may also neutralize the SARS-CoV-2 Omicron variant by performing neutralization assays in Omicron-infected VeroE6 cells and evaluating the outcomes with that of the reference pressure.


The examine outcomes confirmed that sera samples collected after the second dose of COVID-19 mRNA vaccination didn’t present a protecting impact towards the Omicron variant whereas they exhibited potent neutralizing exercise in VeroE6 cells contaminated with the reference Wuhan pressure. This confirms current observations by different research on the restricted capacity of vaccinated and convalescent sera to neutralize the SARS-CoV-2 Omicron variant.

The researchers discovered that mutations within the K417N, E484A, Q493R, Q498R, N501Y, and Y505H residues on the RBD immediately affected Omicron Spike­–human ACE2 binding, resulting in higher binding affinity.

Apparently, the Omicron variant carried mutations at Q498 and Q493, each of which have been reported in mouse-adapted viral strains, together with the just lately developed maVie16 SARS-CoV-2 pressure, which causes extreme COVID-19 in mice. Thus, it’s attainable that Omicron is able to infecting rodents.

Modeling of N-glycosylation websites of the Spike protein confirmed that regardless of the excessive variety of mutations noticed in Omicron, no N-glycosylation websites important for ACE2 binding had been altered in its Spike protein. These information obtained via molecular modeling help earlier findings displaying pre-fusion Omicron Spike protein readily related to human ACE2.

The experiments in VeroE6 cells confirmed that clinical-grade recombinant soluble ACE2, which is a drug candidate at present underneath improvement, strongly neutralized Omicron in VeroE6 cells with considerably enhanced efficiency in comparison with reference isolates of SARS-CoV-2.


The examine findings present that the clinical-grade soluble ACE2 successfully inhibits the SARS-CoV-2 Omicron variant, which proves the precept of an efficient therapeutic method towards Omicron-driven COVID-19 infections. Together with current findings displaying that ACE2 blocks all identified SARS-CoV-2 variants of concern, the outcomes of this examine provide a blueprint for a common agent towards COVID-19 with the potential to forestall or alleviate Omicron infections.

APN01 intravenous infusions have undergone section 2 testing in World Well being Group (WHO) stage 4-6 COVID-19 sufferers. The authors, working with NIH researchers, have developed an APN01 formulation that may be inhaled as an aerosol to immediately intervene with the preliminary steps of SARS-CoV-2 an infection and illness improvement. The effectiveness of this inhalation method in providing safety from SARS-CoV-2 infections has been confirmed in mice contaminated with a SARS-CoV-2 variant that carries two mutations additionally discovered within the Omicron variant. Soluble ACE2/APN01 inhalation is at present present process section 1 trials to find out its security and tolerability.

*Vital discover

bioRxiv publishes preliminary scientific reviews that aren’t peer-reviewed and, due to this fact, shouldn’t be considered conclusive, information scientific follow/health-related habits, or handled as established data.

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