An international team of scientists has shown that the antibodies of a patient recovered from SARS (severe acute respiratory syndrome) are able to naturally block the SARS-CoV-2 coronavirus, causing the current pandemic.
This finding, which is detailed today in the journal Nature, concludes that these antibodies, which can neutralize the virus, could serve to develop antiviral treatments or vaccines.
Antibodies are molecules produced by the immune system to fight infections in the body, either viral or bacteriological.
Within these defenses are monoclonal antibodies, which target a specific protein (antigen) for a pathogen.
Identifying monoclonal antibodies that can bind to the “tip protein” of SARS-CoV-2 and SARS-related coronaviruses (the one that allows entry into human cells), may be helpful in treating or preventing infection by SARS-CoV-2.
In this context, the research, led by Davide Corti, from Vir Biotechnology (Switzerland), has studied the efficacy of monoclonal antibodies extracted from a patient who recovered from SARS in 2003.
The researchers studied the potential of 25 patient antibodies to inhibit SARS-CoV-2 and found eight that could bind both free virus and infected cells.
Of all of them, one candidate, named S309, proved to have a particularly strong neutralizing ability against SARS-CoV-2.
The study, which looked at the crystal structure of S309, showed how the antibody binds to the virus’s top protein.
It also showed that S309, combined with another, less potent antibody that targets a different point in the virus’s top protein, could improve neutralization and reduce the chance of resistant mutations emerging.
The study is a “proof of concept” that suggests that monoclonal antibody combinations may be worth investigating to control SARS-CoV-2, the authors suggest.
However, they caution that no human experiments were performed for the study.