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Osaka Univ. team finds COVID-19-supercharging antibodies

This electron microscope photo provided by the National Institute of Infectious Diseases shows the coronavirus isolated at the institute. (Photo Courtesy of the National Institute of Infectious Diseases)

OSAKA -- A team of scientists including those from Osaka University has discovered coronavirus antibodies that could induce severe COVID-19 symptoms, a discovery which could further help in the development of vaccines, it was announced on May 24.

    Studies have shown that when an individual is infected with the coronavirus or gets vaccinated, neutralizing antibodies are created in the body, which could prevent further infections. The recently discovered antibodies do the opposite and enhance the virus' transmissibility. The research may help determine the risk of developing severe symptoms in each patient and contribute to further vaccine development.

    Some viruses are known to elicit antibodies that help transmissions and trigger antibody-dependent enhancement, which could cause severe symptoms. Such antibodies had been found in people with infectious diseases including severe acute respiratory syndrome (SARS), but had not been known to exist in those with COVID-19.

    Immunology professor Hisashi Arase at Osaka University and other scientists analyzed 76 types of antibodies acquired from immune cells of individuals infected with the coronavirus. SARS-CoV-2 infection occurs when the virus binds to a human cell using the "spike protein" on its surface, and the research team found infection-enhancing antibodies in the protective protein that affect the coronavirus spike protein's N-terminal domain, or NTD. They learned that the infection-enhancing antibodies weakened the effects of neutralizing antibodies. When there was plenty of neutralizing antibodies, the infection-enhancing antibodies did not affect their function.

    When studying the difference of antibodies in those infected with the coronavirus, a large volume of infection-enhancing antibodies were found especially among patients suffering severe symptoms. Meanwhile, in some cases non-infected individuals carried infection-enhancing antibodies, meaning that once they are infected or vaccinated the level of this type of antibody could increase. Arase explained that by looking into the level of infection-enhancing antibodies in a person, it may be possible to tell beforehand if they would get severe symptoms once they are infected.

    The team's finding is expected to appear in the U.S. scientific journal "Cell."

    (Japanese original by Koki Matsumoto, Science & Environment News Department)

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