Antibodies from a SARS-cured patient have been shown to block COVID-19 infection in the laboratory, researchers in another potential breakthrough in the search for a coronavirus treatment announced on Monday.
Scientists based in Switzerland and the United States previously isolated the patient’s antibodies in 2003, following the SARS epidemic that killed 774 people.
They tested 25 different types of antibodies – which target specific protein spikes on viruses – to see if they could prevent cells from being infected with COVID-19.
Both SARS and the pathogen causing COVID-19 are coronaviruses, believed to originate from animals, and therefore have similar structures.
The researchers identified eight antibodies that could bind both COVID-19 and infected cells.
One candidate, known as S309, was found to have “particularly strong neutralizing activity” against COVID-19.
By combining S309 with other less potent antibodies, they were able to target different sites on the protein’s spike, reducing its potential for mutation.
The COVID-19 pandemic has seen hundreds of trials for effective treatment launched, including some involving the use of antibodies from recovered patients.
Although there was no human experience in the study, published in the journal Nature, its authors stated that their results represent “proof of concept” that antibodies to SARS can prevent infection and serious spread to COVID-19.
“These results pave the way for the use of antibody cocktails containing S309 and S309 for prophylaxis in people at high risk of exposure or as post-exposure therapy to limit or treat serious illness”, they write.