In parallel with the race for the vaccine, the race towards treatments for Covid-19 is being played out. Three drugs have recently shown their effectiveness in neutralizing the virus.
- A mini synthetic antibody made it possible to neutralize the virus in the laboratory and prevent it from attaching to the receptors of our cells to infect them.
- Another nanobody has shown its effectiveness in blocking the virus in llamas.
- A nasal spray, which can be made quickly and easily, has prevented ferrets, which catch viruses through the nose like humans, from becoming infected with SARS-CoV-2.
What if the solution to get out of the pandemic was treatment rather than a vaccine? While the race for a vaccine is in full swing, the race for finding a treatment is advancing at least as quickly. In recent days, three drugs have been the subject of scientific publications presenting their effectiveness in neutralizing the virus.
Nanobodies, a lead explored by two teams of researchers
The first treatment track is developed by German researchers and is based on a “sybody”, a synthetic mini antibody, which was able to block the virus in the laboratory. More precisely, this small antibody neutralizes the receptor of the virus which allows it to infect cells. SARS-CoV-2 uses the ACE2 receptor, present on the surface of our cells, as a gateway to them to infect them. Researchers at the European Molecular Biology Laboratory (EMBL), based in Hamburg, have succeeded in finding a product that binds more strongly to the virus than the receptor in our cells to prevent it from accessing it and infecting us. They presented the results of their research on November 4 in the journal NatureCommunications.
These small antibodies, called “nanobodies”, are present in camels and llamas, studied since the beginning of the crisis for the effectiveness of their antibodies. “Nature is our best inventor”, estimated Yi Shi, professor of cell biology at the University of Pittsburgh (United States) who is also working on this treatment solution. The two teams of researchers are working to find the most effective nanobody. The German researchers focused their study on “Sb23”, for sybody number 23, which showed the best results in neutralizing the SARS-CoV-2 virus in the laboratory. The next step is to verify the effectiveness of Sb23 in humans.
American researchers who are also working on a nanobody have shown the effectiveness of this treatment after carrying out tests on a llama who was immunized against SARS-CoV-2. They presented their findings Nov. 5 in the journal Science. A single fraction of the injected nanogram managed to neutralize the virus enough to prevent the infection of a million cells. This nanobody can be stored at room temperature and does not require refrigeration, which can make its deployment around the world more complicated. Another advantage is that it can be inhaled and taking it is therefore less restrictive than a blood test and directly penetrates the lungs, where their activity is most needed. “Nanobodies could potentially cost a lot lessYi Shi continued. They are ideal to deal with the urgency and scale of the current crisis.”
A nasal spray that prevents infection
The other avenue of treatment is based on a nasal spray that blocks the absorption of the SARS-CoV-2 virus. The trials are being conducted by US researchers from Columbia University in collaboration with scientists from Cornell University in New York and Erasmus Medical Center in the Netherlands. The results of their study carried out on ferrets were presented on November 5 in a pre-publication published on BioRxiv. The spray contains a lipopeptide, a cholesterol particle linked to a chain of amino acids. This lipopeptide prevents the virus from attaching itself to our cells to infect them. “It’s like closing a zipper but putting another one inside, so the two sides can’t meet”, describes Matteo Porotto, a microbiologist at Columbia University and one of the authors of the article.
The researchers administered the spray to six ferrets and a placebo to six others. The latter were placed in three cages with in each two ferrets which received the spray and two which received the placebo. A ferret that was deliberately infected with the virus was placed in each cage a day or two earlier. Conducting this study on ferrets is interesting because, like humans, they can pick up viruses through their noses. After 24 hours, all of the ferrets that received the placebo were infected with the virus, while none of the ferrets that received the nasal spray were. “Virus replication has been completely blocked”, observed the researchers.
Researchers now want to conduct their studies on humans. “If it works well in humans, you could sleep in a bed with an infected person or be with your infected children and still be safe.”, welcomed Anne Moscona, pediatrician and microbiologist at Columbia University and co-author of the study. Moreover, this spray can be made quickly and inexpensively since it suffices to mix the freeze-dried white powder with sugar and water. “Because lipopeptides can be shipped as a dry powder, they could be used even in rural areas of poor countries without refrigeration.”, continued Anne Moscona.
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