BREAKING! COVID-19 Antibodies: American Researchers Develop Synthetic Antibody ACE2-IgG1 That Could Prevent And Treat COVID-19
: Researchers from Tulane University-New Orleans, University of Illinois-Chicago and University of Georgia have created a synthetic antibody that on mouse models demonstrated to neutralize the SARS-CoV-2 coronavirus. This could help prevent infection as well as treat COVID-19 in those who already have it.
Typically the SARS-CoV-2 coronavirus, gains entry into cells in the body using a receptor called angiotensin-converting enzyme 2 (ACE2).
These ACE2 receptors are present on the surface of cells in the airways, the lungs and many other organs and tissues including endothelial cells. After a person inhales viral particles, spike proteins on the outside of the virus bind to this receptor, which allows the virus to enter cells and cause disease.
The American research team has now developed a synthetic antibody that stops the virus from attaching to the ACE2 receptor, ultimately preventing infection.
Their research findings are published on a preprint server but are being peer-reviewed. https://www.biorxiv.org/content/10.1101/2020.06.15.152157v1
The study team says that healthcare professionals could use the antibody both before and after a person has had exposure to SARS-CoV-2. It could be especially beneficial for people who cannot receive a vaccine for health reasons.
In order to trick the virus, the researchers behind the study designed a “decoy” ACE2, which the virus recognizes in the same way it does the real thing. However, it is not attached to cells in the body.
This new decoy protein intercepts to neutralize the virus before it can attach to ACE2 on cells and cause infection.
However although scientists have used ACE2 in a soluble form before and it is safe in humans, it generally does not stay in the body for long and cannot reach the lining of the lungs which is crucial for treating a respiratory virus.
In order to overcome these problems, the study team attached ACE2 to the end of an antibody to increase its stability and transport in the body. They created four different antibodies, each with different mutations, to increase the ability of the drug to bind to the virus, its stability, and its half-life.
Almost all of the antibodies worked against SARS-CoV-2, but one, called MDR504, was particularly effective. The virus bound more tightly to this particular antibody than it does to the natural ACE2 in the body.
Significantly this means that the antibody could effectively outcompete the ACE2 expressed on bodily cells, preventing the virus from infecting them.
Subsequently in the next phase of their experiments, the researchers tested the drug in cells in culture using a pseudovirus very similar to SARS-CoV-2. They found that MDR504 effectively neutralized the virus and blocked it from entering the cells.
The researchers next injected the antibody into mice, where it reached the lungs at levels likely high enough to stop the virus from entering the cells lining these organs.
It was observed that the antibody remained in the system for a long time. After
6 days, half of what the researchers injected was still in circulation in the mice.
The team also say that the antibody could be dual purpose; they could use it to prevent infection and as a treatment for COVID-19.
They suggest administering it to high risk groups, such as healthcare workers and first responders, to prevent them from contracting the novel coronavirus.
Since the drug is an antibody, a doctor would need to inject it directly into the circulation rather than asking a person to take it orally. Also, because it also has a long half-life, these injections could be relatively infrequent, the researchers suggest.
Professor Dr Jay K. Kolls from Tulane University who is the lead researchers told Thailand Medical News, “Based on our data, we think it would work as an injection either once every 2 weeks or maybe even once a month.”
Frontline healthcare professionals could also use the drug in place of a vaccine (once one arrives) for those too vulnerable to receive one. This might include people receiving immunosuppressant treatment for an organ transplant or an autoimmune condition.
The research team has already started collaborating with a biotechnology company to further develop the treatment and start the necessary clinical trials in humans.
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