A combination of antibodies, including those from a patient who had recovered from the 2002-03 SARS pandemic virus infection, can effectively block the novel coronavirus, according to a study which may lead to new therapeutics against COVID-19.
The study, published in the journal Nature, noted that antibodies, produced by the immune system of recovered people, can neutralise the virus, and help in the development of anti-viral treatments or vaccines.
A particular kind of antibodies can target one specific protein on a pathogen, the researchers, including those from the University of Washington in the US, said.
They added that identifying these monoclonal antibodies that can bind to the spike protein found on the novel coronavirus, SARS-CoV-2, and other similar viruses, may aid efforts to treat or prevent COVID-19.
In the research, Davide Corti and his colleagues identified monoclonal antibodies from a patient who recovered from the 2002-03 SARS pandemic disease.
They said these could inhibit SARS-related coronaviruses from both humans and animals.
When the scientists investigated the potential for 25 of these antibodies to inhibit SARS-CoV-2, they found that eight of them could bind to both the free virus, and infected cells.
One candidate, named S309, showed particularly strong neutralising activity against SARS-CoV-2, they said.
By understanding the crystal structure of S309, the scientists demonstrated how the antibody binds to the viral spike protein, which aids in the entry of the pathogen into host cells.
They revealed that S309 can act in combination with another, less potent, antibody that targets a different site on the spike protein of the virus.
This tandem activity could enhance neutralisation while reducing the chance of resistant mutations emerging, the scientists noted in the study.
Based on the findings, they suggested that cocktails of monoclonal antibodies may be worth exploring to control SARS-CoV-2.
However, the study noted that the results are yet to be validated in humans clinical trials.