Antibody-laden nasal spray could provide protection and treatment against COVID-19

According to a study published in the scientific journal Nature, nasal spray loaded with design antibody provides strong protection against SARS-CoV-2 coronavirus variants, at least in mice.

Since the early days of the pandemic, scientists have been developing antibodies as treatments for COVID-19. Currently, several of these antibodies are in advanced stages of clinical trials, and some regulatory agencies in the United States and elsewhere have approved it for emergency use.

However, among physicians, “antibody treatments have not been very popular“, according to Zhiqiang An, an antibody engineer at the University of Texas Health Sciences Center at Houston. This is in part because those that are available are given through intravenous infusions rather than directly into the respiratory tract, where the virus is primarily found, so high doses are needed to be effective. Another challenge is the emergence of variants of SARS-CoV-2 which appear to be resistant to some existing antibodies..

That’s why An and his colleagues set out to design an antibody that could be delivered directly into the nose.. They scanned a library of antibodies from healthy humans and focused on those who might recognize a component of SARS-CoV-2 that the virus uses to adhere to and enter cells. Among the promising candidates were the IgG antibodies, which are relatively slow to appear after infection, but are designed specifically for the invading pathogen.

The team linked fragments of IgG targeting SARS-CoV-2 to another type of molecule: IgM antibodies., which act as rapid first responders to a wide range of infections. Genetically modified IgMs had a much stronger “neutralizing” effect against over 20 variants of SARS-CoV-2 than IgG alone. When injected into the nose of mice six hours before or six hours after infection, the modified IgM significantly reduced the amount of virus in the lungs of rodents two days after infection, the research team reported. .

This work is a “great feat of engineering”, opinion Guy Gorochov, immunologist at the Sorbonne University in Paris. But add that there are open questions, such as how long these antibodies will stay in humans.

The expert from the University of Texas at Houston Health Sciences Center sees these antibodies as a kind of chemical mask that anyone who has been exposed to SARS-CoV-2 could wear, and as an additional line of defense for people who might not be. fully protected by vaccines. Since IgM molecules are relatively stable, it may be possible to formulate them into a nasal spray that will be purchased at a drugstore and stored for emergency use., explained An.

IGM Biosciences, a Mountain View, Calif., Biotechnology company that collaborated on An’s study, will test for the antibody in clinical trials.

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