Researchers from the Duke Human Vaccine Institute (DHVI) and the University of North Carolina at Chapel Hill (UNC-Chapel Hill) found the proverbial needle in the haystack when they discovered an antibody that limits the severity of infections from a variety of coronaviruses, including those that cause COVID-19 as well as the original SARS. They reported their findings in Science Translational Medicine late last year.

“This antibody has the potential to be a therapeutic for the current epidemic,” said co-senior author Barton Haynes, Director of DHVI. “It could also be available for future outbreaks, if or when other coronaviruses jump from their natural animal hosts to humans.”

Haynes and his team at DHVI isolated the antibody after analysing the blood from a patient who had been infected with SARS-CoV-1—the virus responsible for the SARS outbreak back in 2003—and the blood of a current COVID-19 patient.

Studying the different antibodies that these patients generated in response to the two coronaviruses, the researchers focused on those that attached to binding sites on the surface of the virus that did not change, even as the viruses mutated. They found 1,700 antibodies that had the potential to be highly effective across different lineages of coronaviruses.

It was only after painstakingly sifting through these antibodies one by one that the Duke researchers whittled their list down to 50 antibodies that had the ability to bind to both the SARS-CoV-1 virus as well as SARS-CoV-2. Upon further investigation, they discovered that one of these cross-binding antibodies was especially potent and could bind to a multitude of animal coronaviruses in addition to the two human-infecting pathogens.

“This antibody binds to the coronavirus at a location that is conserved across numerous mutations and variations,” Haynes said. “As a result, it can neutralise a wide range of coronaviruses.”

With the antibody isolated, that’s when the researchers at UNC came into play with their expertise in animal coronaviruses. The UNC team, led by co-senior author Ralph Baric, a professor of epidemiology at UNC Gillings School of Global Public Health, tested the antibody in an animal model to determine whether it could effectively block infections or minimise the infections that occurred.

To the team’s amazement, they found that the antibody could do both. When given before an infection, the antibody provided protection from developing SARS, COVID-19 and the variants of SARS-CoV-2, along with many animal coronaviruses that have the potential to cause human pandemics.

“The findings provide a template for the rational design of universal vaccine strategies that are variant-proof and provide broad protection from known and emerging coronaviruses,” Baric said.

When the antibody was given after an infection occurred, the researchers also observed that the frequency and severity of lung symptoms was reduced.

“The therapeutic activity even after mice were infected suggests that this could be a treatment deployed in the current pandemic but also stockpiled to prevent the spread of a future outbreak or epidemic with a SARS-related virus,” said co-lead author David Martinez, a post-doctoral researcher in the Department of Epidemiology at UNC’s Gillings School.

This is but the latest discovery from scientists’ quest to find a dream vaccine. In the pursuit of a pan-coronavirus vaccine, Haynes and his team found a receptor-binding domain site that made SARS-CoV-2, its circulating variants and other SARS-related bat viruses highly vulnerable to cross-neutralising antibodies, while at Duke-NUS, Professor Wang Linfa and collaborators identified a neutralising antibody with the power to block infection not just from a variety of SARS-causing beta-coronaviruses.

And all of them share a common goal: to prevent future coronaviruses, such as SARS-CoV-3 and even SARS-CoV-4.