The study develops a rapid test to identify the efficacy of antibodies to Covid-19 variants
Biomedical engineers Duke University has developed a test to quickly and easily assess how well human neutralizing antibodies fight multiple COVID-19 variants, including Delta and the new Omicron variant.
The study is published in the “Science Advances Journal”.
This test could potentially tell physicians how protected the patient is from new variants and currently circulating variations in the community, or which monoclonal antibodies to treat a patient with COVID-19.
“At the moment, we really don’t have a quick way to evaluate variants, neither their presence in an individual nor the ability of the antibodies we have to affect,” said Cameron Wolfe, Assistant Professor of Medicine at Duke University School of Medicine.
“It’s one of the lingering fears that as we successfully vaccinate more and more people, a variant may emerge that most radically avoids the neutralization of antibodies caused by vaccines. And if that fear materialized – if Omicron turned out to be the worst case scenario – how would we know fast enough?” Wolfe added.
“When we developed a treatment point test for COVID-19 antibodies and biomarkers, we realized that the ability of antibodies to neutralize certain variants may be beneficial, so we built the test around this idea,” he said. Ashutosh Chilkoti, Alan L. Kaganov Distinguished Professor of Duke and Director of Biomedical Engineering.
“It only took us a week or two before we included the Delta variant in our test, and it could easily be expanded to include the Omicron variant. added.
Researchers have named their test the COVID-19 Variant Spike-ACE2-Competitive Antibody Neutralization Test, or CoVariant-SCAN for short. The technique of the test was based on a polymer brush coating that acted as a kind of non-stick coating, preventing anything other than the desired biomarkers from adhering to the test glass when wet. The high efficiency of this non-stick shield made the test incredibly sensitive even to low levels of objects. The approach allowed researchers to print different molecular traps on different regions of the slide to obtain multiple biomarkers at once.
In this application, researchers printed fluorescent human ACE2 proteins – cell targets of the infamous viral spike protein – on a slide. They also weighted peak proteins specific for each COVID-19 variant at different sites. When the assay was run, the ACE2 proteins detached from the slide and were trapped by the peak proteins still attached to the slide, causing the slide to glow.
But in the presence of neutralizing antibodies, the peak proteins were no longer able to adhere to ACE2 proteins, resulting in less glow of the slide, indicating the efficacy of the antibodies. By printing different variants of the COVID-19 peak protein into different parts of the slide, the researchers were able to see how effectively the antibodies prevented each variant from adhering to its human cell target simultaneously.
The researchers tested the technique in a number of different ways. They experimented with monoclonal antibodies derived from real patients or commercial prophylactic treatment with Regeneron. They also tested plasma taken from healthy people who had been vaccinated and were currently infected with the virus.
“In all of our tests, the results largely mimic what we’ve seen in the literature,” he said Jake Heggestad, A doctoral student working at Chilkoti Laboratory.
“And in this case, not finding a new one is a good sign because it means our test works just as well as the methods currently in use,” Heggestad added.
Although they produced similar results, the critical difference between CoVariant-SCAN and current methods is the speed and ease with which they can produce results. Typical current approaches require the isolation of live viruses and the culturing of cells, which can take 24 hours or more and requires a wide range of security measures and especially trained technicians. CoVariant-SCAN, on the other hand, requires no live virus, is easy to use in most settings, and takes less than an hour – possibly just 15 minutes – to produce accurate results.
Going forward, Heggestad and the Chilkoti Laboratory are working to streamline the technology into a microfluidic chip that could be mass-produced and report results with just a few drops of blood, plasma, or other liquid sample containing antibodies. This approach has already been shown to work in a similar test that can distinguish COVID-19 from other coronaviruses.
“We would like real-time visibility from rising variations and understanding who still has functional immunity,” Wolfe said.
“Furthermore, this suggests that there may be a technique that allows you to quickly assess which synthetic monoclonal antibody might be best given to a patient with a particular emerging variant. At the moment, we really don’t have a real-time way to know that, so we can trust epidemiological data that may follow weeks behind, “Wolfe added.
“The opposite is also true,” Wolfe continued.
“We can pre-screen an individual’s antibodies and predict if they were adequately protected against a particular variant he may encounter on his way or appearing in his territory. We currently have no way to do that. But a test like CoVariant-SCAN could make all of these scenarios possible. “Wolfe decided.
This work was supported by the National Institutes of Health, the National Science Foundation, and the Department of Defense / Defense Advanced Research Projects Agency.
Source: ANI